Rules of Thumb

v4.20 · 24 August 2026

• The Salmonella figure is now a percentage instead of a “log reduction”. A soft-boiled egg removes about 99.9998% of anything present — the same number as before, in a form you can actually read
• That is a removal rate, not a survival chance. 99.9998% removed does not mean a 99.9998% chance the egg is fine, and the page says so plainly — the release checks fail the build if that distinction ever goes missing
• For the question people really have — how likely am I to get ill — we quote the people qualified to answer it. The joint FAO/WHO assessment puts it around 1 in 5 million to 1 in 220,000 per serving. Their figure, not ours, and labelled as such. Their work also finds storage matters more than cooking time
• The chart now labels both scales side by side — 90%, 99%, 99.9% against 1, 2, 3 — so you can see how the two relate instead of taking it on trust
• And the estimate is stamped with the egg it is for, updating with size, fridge or room temperature, doneness, method and altitude

v4.19 · 24 August 2026

• The Egg Timer now shows how much a cook reduces Salmonella, plotted against time. Almost all of it happens in the last thirty seconds, which the curve makes obvious in a way a number cannot
• It is deliberately framed as a best case, not a verdict. The figure is calculated at the edge of the yolk, which is not the coolest part of an egg — the centre gets less. So a low number tells you something real, and a high number does not clear the egg. It can rule a cook out; it can never rule one in
• It never says an egg is safe, and it never will. That is enforced by the release checks, which read the page's own wording and fail the build if it ever starts promising safety, a percentage, or the elimination of anything
• The research it draws on is quoted with its limits attached. The study measured liquid yolk held at one steady temperature — it made no claim about whole eggs in a pan, and the page says that the leap from one to the other is ours
• Both official positions are cited, because they disagree. US guidance wants eggs cooked to 63 °C; UK guidance treats Lion-marked eggs as fine to eat runny. Follow whichever regulates your eggs — not a chart on a website

v4.18 · 23 August 2026

• The search box on the front page no longer shows a yellow rectangle when you click into it. It now lights up in the site's blue, exactly like the full search page does
• The cause was a missing colour setting. The page asked for a blue border and never said which blue, so the browser threw the request away entirely and fell back to a general-purpose amber outline meant for everything else on the site
• A previous release tried to fix this and skipped the one page that had it — it searched for the colour's name, which appears on a page that is missing the setting just as much as on one that has it
• The release checks now catch it properly, and were tested against the old version of the site to confirm they spot the original fault

v4.17 · 23 August 2026

• Charts now fit the screen on a phone instead of sliding sideways. Almost every chart on the site was drawn for a desktop and had to be scrolled to see its axis — 148 of them, on 105 pages
• The trick is to hide the handful of labels that actually collide, rather than make the whole chart wider. On the Moody diagram that is two: the axis titles, whose wording already appears in the caption underneath
• Nothing is thrown away. Turn your phone sideways or open the page on a laptop and every label comes straight back, and the data table under each chart lists the full set whatever the screen is doing
• The old rule was hiding the problem: it demanded 60% of a chart's width for its labels, which was both too little to stop them overlapping and too much to fit a phone. It managed to do neither job

v4.16 · 23 August 2026

• Every slider, dropdown and checkbox on all 101 calculators is now pushed to its limits automatically before a release — nearly two thousand settings tried in about a minute, watching for impossible numbers and controls that do nothing
• This is what catches the awkward ones. The previous check confirms a page opens correctly; it cannot find a calculator that only breaks when you drag a slider all the way to one end, which is exactly how one of them used to report infinite stress
• Tested against the site as it was before those bugs were fixed, where it names both of them and the exact setting that triggers each
• All 101 came back clean. Nothing on the site itself changed

v4.15 · 23 August 2026

• Every calculator page is now started up and checked automatically before any release. Until now the pre-release checks read the pages but never actually ran them — which is how a chart that drew at “not a number” and a page with a broken script both made it through in the past
• The new check was tested against history before being trusted: pointed at an archived copy of the site from before an old bug was fixed, it catches exactly that bug
• Nothing on the site itself changed — this one is insurance for every release that follows

v4.14 · 23 August 2026

• Opening a chart at full size no longer gives you scrollbars. A change last week made charts grow to use up spare height, which meant some of them ended up wider than the window and you had to scroll sideways to find the axis. That was the wrong trade — the whole chart is now visible, always
• And charts on a phone stop scrolling for the sake of a few pixels. Several were drawn just slightly wider than the column they sit in and refused to give up the difference, clipping their own axis rather than shrinking by five per cent
• Large charts still scroll on a narrow screen, because squeezing them into a phone column would make the labels too small to read. That one is a deliberate choice

v4.13 · 23 August 2026

• The shine on the glass has gone, because it looked like a temperature. The simulator colours the drink by how hot it is, so a highlight painted down one side reads as a warm stripe that is not really there
• The glass is now a single flat tone — it still reads as glass from its thickness and its edge, without pretending there is a window off to one side
• Checked rather than eyeballed: the drink is a cylinder, so the picture has to be a perfect mirror image about its centre line. It now is, exactly

v4.12 · 23 August 2026

• Start the timer and the simulation now runs with it — one real minute to one simulated minute. Before, the countdown ticked away next to a picture frozen wherever you had last dragged it, so the clock and the drink disagreed
• There is a proper timeline. One band for each stage — the freezer, then the fridge or the table you move it to — a marker at every point worth knowing about, and how long is left until each of them
• The timer is now the biggest thing under the picture, rather than a small panel at the bottom of the settings
• And the bottles no longer look like a flight of stairs. The sloped shoulder of a bottle was being drawn one square step per row of the simulation grid, with a dark fringe smeared along every angled edge. Both are gone

v4.11 · 23 August 2026

• A large arrow was sitting on top of the charts on fifteen pages. The little “expand” button in the corner of a chart had its icon blown up to the full width of the button, so the thing meant to help you see the chart was covering it
• Opening a chart full size now actually uses the screen. It was filling the width and leaving half the height empty — worse on a phone, where expanding a chart gave you a small chart in a large blank space
• Three charts on the SUVAT calculator could never be expanded at all, because the site only checked whether they were charts before they had been drawn
• And the yellow box around the search field is gone. Thirty pages were missing their accent colour, so the outline that shows which control you are on fell back to yellow instead of matching the page

v4.10 · 23 August 2026

• Drinks can now freeze — and they do not freeze at zero. A beer goes at about −2°C, cola nearer −3, wine −5.5, and whisky not until −27, which is why the freezer never touches it. Until now the simulation sailed straight past freezing as though it were not there
• It will warn you before you ruin something. Leave a beer bottle in the freezer and the page now tells you when ice starts forming, when it turns to slush, and when the bottle bursts — because water expands about 9% as it freezes and a sealed bottle has nowhere to put it. Glass gives no warning at all; a can bulges first
• There are open pint glasses now, and an open glass is not just a different shape. A cold one collects condensation, and that actually warms the drink — the same reason your pint leaves a ring on the table. A pint takes several minutes longer to chill on a humid day
• And you can take it back out again. Chill it, then watch it warm up on the table — or blast it in the freezer and move it to the fridge partway. A real-time timer will tell you when, even if you switch tabs

v4.09 · 23 August 2026

• Five of the physics simulators were checked by working the same problems out a second time, independently — golf ball flight, the pendulum, Galileo’s falling bodies, collisions, and the rocket equation. Where the maths has an exact answer, the check uses it rather than simulating anything
• The rocket page had a preset that could not do the job its name claimed. “Falcon 9 (LEO)” came up about 650 m/s short of reaching orbit. The rocket is fine — the simulation gives each stage a single engine efficiency, and a first stage is roughly 10% more efficient once it is out of the thick air. The page now explains that instead of leaving you to wonder
• The familiar pendulum formula is always wrong in the same direction. A real pendulum swings slower than the textbook says — by a fifth at a 90° swing, and without limit as it approaches vertical
• A Newton’s cradle does not count balls. Nothing in the code knows that two in should mean two out; it falls out of each pair handing on what it receives

v4.08 · 23 August 2026

• The page can now do a reverse sear — low oven first, pan last — where before it said it could not. It turned out not to need a new simulation at all: an oven is just every side of the steak exposed to hot air instead of one side on metal
• And it disagrees with the received wisdom. Reverse searing is supposed to cook more evenly. It does — but only above about 30 mm. Below that it is worse than simply turning the steak often in a hot pan, and it takes five times as long. A thin steak has nothing to protect
• Half the heat in an oven is the walls glowing at the food, not the hot air. Treating an oven as warm air alone gets the time badly wrong
• The page tells you which side of that 30 mm line your steak is on rather than recommending a method

v4.07 · 23 August 2026

• You can finally put the ice in the drink. It turns out two cubes only take a warm can to 13°C — and the amount that actually gets you to 8°C leaves about an eighth of the glass as water. That trade-off is the whole argument, and the tool now settles it
• The page told you to add salt to the ice bath, and the simulation ignored you. The code refused to let the bath go below freezing. Now it follows the real salt-water freezing curve, and a properly salted bath halves the time again — to about a minute
• Whether a wet towel works depends entirely on how dry the air is, which is why everyone disagrees about it. On a hot dry day it genuinely chills. At normal humidity it only stops the drink warming up. In muggy air it does nothing at all
• And the page had one of its own explanations backwards — it said the surface was the bottleneck when the drink was slow to cool, when it is the middle

v4.06 · 23 August 2026

• The beverage simulation has been checked by solving the whole thing again from scratch, independently, rather than just checking the numbers fed into it. The two agree on how much heat leaves the can to within a fifth of a percent
• The pendulum page said it ignored air resistance. It does not — drag is switched on by default, and always has been. The page now describes what it actually does
• Thirty-eight pages claimed they had never changed since the very first release. Several had been rewritten more than once. They were reporting “no entries to show” as “nothing ever happened”
• Chilling a drink, cooking a steak and boiling an egg are the same piece of physics pointed at different objects. The three calculators now link to each other
• And a fault found while doing that: opening any tool with a “.html” address — including offline — quietly threw away its hand-picked related links and substituted others. It looked completely normal

v4.05 · 23 August 2026

• Every control on all 101 calculators was driven to its extremes to look for numbers that break. Two tools were doing it
• Three of the four small charts on Compound Interest were missing their gridlines and axis figures — and had been since they were written. The labels were in the page all along; they were being positioned at “not a number”, so the browser simply never drew them
• The Spring Rate calculator would tell you a spring had infinite stress. Wind the coil down until it is no wider than the wire it is made from and the standard formula divides by zero. It now says what is wrong instead: that is not a spring
• The other 99 came back clean

v4.04 · 23 August 2026

• The picture already knew about the milk. The number did not. The mug on screen has always lightened when you add milk, but the strength figure beside it was the strength of the tea before any went in
• It makes more difference than you would think: a 30 ml splash in a 200 ml mug takes 13% off, and a proper builder’s 50 ml takes a fifth. The readout now shows both — what came out of the leaf, and what is in the cup
• Half the strength is out in the first 97 seconds and the other half takes five and a half minutes. A three-minute brew is at 72% of everything that bag will ever give, so “leave it a bit longer” does less than people imagine
• And the page now admits it has no idea how hot your water is — which after time is the biggest lever of the lot

v4.03 · 23 August 2026

• Checked against an independent implementation on every single day from 1900 to 2100 — 73,414 dates — with not one disagreement, in either the week number or the year it belongs to
• That matters more than it sounds. Week numbering is full of traps: the 30th of December can belong to next year, the 1st of January to last year, and some years have 53 weeks. Most hand-written implementations get one of those wrong
• Nothing needed fixing, which is the honest result. The page now states what it assumes — dates in UTC with no time of day, and two of the world’s week conventions rather than all of them

v4.02 · 23 August 2026

• Rent goes up every year in this comparison. The costs of owning never do. Property tax, maintenance and insurance are all worked out from the price you paid and then held there for good, while the rent compounds
• That is worth about eleven years. Let those three rise at the same 3% the page already applies to rent and the break-even point moves from year 19 to year 30 — at 4% a year, buying never catches up at all inside thirty years
• The sums are unchanged — some of that flatness is quite right, since a fixed-rate mortgage really does stay put. But it is now stated plainly rather than left for you to notice
• And the hard part was already right: both the renter and the buyer invest whatever money they are not spending, including the deposit. Most calculators of this kind quietly skip that, which is how they end up recommending buying

v4.01 · 23 August 2026

• The in-between years are estimates, and the page now says how rough. Prices are stored every five years before 1950 and the gaps are filled assuming inflation ran steadily across them — which it very much did not in 1920 or the 1970s
• You can measure the cost of that from the page’s own figures: hide a stored year and rebuild it from its neighbours. Modern years come back within 1%; 1920 comes back 43% low. An interwar answer is an order of magnitude, not a figure
• Everything else checked out. The arithmetic, the round-trips, and the fact that the index correctly falls between 1920 and 1940 — any tool assuming money always loses value gets the interwar years exactly backwards

v4.00 · 23 August 2026

• The engine table shows the textbook answer being wrong in an interesting way. Piston speed at 90° comes out at almost exactly π/2 times the average — the value in every textbook — and the real peak is earlier, at 75°, and higher. The familiar number is correct, just not where everyone puts it
• Dice & Coin compares theory with what you actually rolled, outcome by outcome. A thousand rolls of two dice gave seven 173 times: 17.3% against a theoretical 16.7%
• Speed Test says where you sit among countries as a percentage rather than a position on a curve — and no longer claims the fastest country is faster than 100% of countries, which it cannot be

v3.99 · 23 August 2026

• Column Buckling now shows the number that should frighten you. Sideways deflection reads 0.0 mm at 80%, 90%, 95% and 100% of the critical load — and 56.9 mm just past it. A column carrying 95% of what will destroy it looks exactly like one carrying 20%, which is precisely why buckling gives no warning
• Integral Windup compares all three fixes at once rather than only the one you have selected: no protection overshoots 12.8%, clamping overshoots not at all, and back-calculation gets there fastest for about one percent
• Two of its column headings were changed because they read as a contradiction — a response that never overshoots gets close enough to count as settled some time before it actually reaches the target, and the old labels made that look like an error

v3.98 · 23 August 2026

• Three more charts show their numbers: Resistor Colour Code, Heat Loss and Waist-to-Height
• The resistor table finds a gap you cannot buy. Standard E24 values at ±5% overlap each other all the way up — so any value in between is covered by something real — until 5.6k and 6.2k, which leave a 10 Ω hole between them that no resistor in the series can fill
• The heat-loss table gives watts per degree, which is the house itself rather than today’s weather — the number that stays true when the forecast changes
• And the waist table turns the ratio into a tape measure: at 170 cm the boundary is 85 cm, at 180 it is 90. Rather easier to check than a line on a graph

v3.97 · 23 August 2026

• Four more charts show their numbers: both Data Transfer Time charts, Password Strength and Refresh Rate
• The transfer table shows an upgrade buying nothing. With a TCP window capping you at 52 Mbps, a 100 Mbps line and a gigabit line finish the same file in the same 38 minutes — four identical rows making the case better than a flattening curve ever could
• The password table answers the question the graph only implies: how long is long enough. Seven Diceware words, or thirteen characters from a full keyboard set, or eighteen if you stick to lowercase
• And the refresh-rate table reports the worst frames, not the typical one — a screen can hold a perfect average and still stutter, and that only shows up in the tail

v3.96 · 23 August 2026

• Four more charts show their numbers: Motor Starting, First-Order Lag, On-Off Control and A/B Test — readable, copyable, and read out when you hover the chart
• The motor table answers the question the graph only implies: how much starting torque you get per amp of inrush. Direct-on-line, star-delta and an autotransformer all score exactly the same, because reducing the voltage costs you torque in the same proportion — a soft starter is worse still, and only a VFD actually wins
• The on-off table shows a heating system is worked hardest at half output, not at the extremes: cycling peaks at 50% duty and falls away evenly on both sides
• And the A/B test table gives plain totals, because that chart’s scale is logarithmic and almost everyone reads those wrongly

v3.95 · 23 August 2026

• The inflation slider looked broken. Drag it from 0% to 12% on a UK plan and nothing moves — which is correct, and gave you no way of knowing that
• It now tells you why. Everything here is in today’s money, and a rate of “RPI plus 3%” is just 3% once inflation is taken out. Inflation changes the number on your statement, not what the loan costs you
• On a New Zealand loan it matters a great deal, and the note says so: that loan charges no interest at all, so inflation quietly shrinks it. At 8% inflation you repay about NZ$1,450 less over the life of it
• And on the US plans it admits to an approximation rather than claiming the figure cancels out

v3.94 · 23 August 2026

• Four more charts show their numbers: Student Loan, Battery Sizing and both of the Concrete Mix charts. Readable, copyable, and available to a screen reader — and hovering the chart reads out the same figures
• The student-loan table shows something the graph could not. Repayments stop altogether around year 17: you pay £4,116 by year 15 and £4,176 by year 30, because the repayment threshold climbs faster than the salary does. That is the model working correctly, and it is easier to believe as a column of numbers
• The battery table is checkable against the physics. At ten times the rated current a good lithium cell still gives 89% of its capacity and a tired lead-acid gives 50% — and at the rated current every chemistry gives 100%, which is exactly why the number on the label tells you so little

v3.93 · 23 August 2026

• Four more charts now show their numbers. Sweat Rate, Currency Converter, EV Charging and Heart Rate Zones each have a “View data as table” panel you can read, copy or hand to a screen reader — and hovering the chart now reads out those same figures
• The heart-rate table adds a column the chart could only hint at: how far the four max-heart-rate formulas disagree. It is 12 beats at age 18 and 25 at 83, which is rather the reason that page exists
• The currency history lists 22 days for a 30-day window, because the European Central Bank only publishes on working days — the gaps are real, not missing data

v3.92 · 22 August 2026

• Hover over a chart and it tells you the numbers under your cursor. A guide line follows the pointer and a small panel shows that point’s values — on the PID step response, the time, the output, the setpoint and the error
• Those are the page’s own figures, not a guess. The readout uses the same data that already sits behind “View data as table” under each chart, so what you hover matches what you can read and copy
• Charts you can already drag are left alone — they have their own marker, and two readouts arguing over one chart helps nobody
• Mouse and trackpad only. On a touchscreen there is no such thing as hovering — the panel would appear on your first tap and then stay put

v3.91 · 22 August 2026

• Charts too wide for your screen now have an “expand” button. Tap it and the chart opens at full size, where you can pan around it — on a phone the Moody diagram goes from showing about two thirds of itself to all of it
• It only appears where it helps. A chart that already fits, or is cut off by only a sliver, does not offer it — and on a desktop screen none of them do
• The chart stays live while expanded, so anything you can drag still drags, and the numbers keep updating as you change the inputs
• Escape closes it, as does tapping outside, and keyboard focus goes where it should on the way in and on the way back out

v3.90 · 22 August 2026

• Big charts were being squashed too far on a phone. The wide ones — the Moody diagram, the mortgage and compound-interest curves — were shrunk to fit a narrow screen, and their axis numbers ended up sitting on top of the axis labels
• The text was never too small — it is held at a fixed readable size on every chart whatever the screen. There simply was not enough room left between the labels once the chart had been squeezed
• Wide charts now keep enough width and scroll sideways instead. On the Moody diagram that takes six overlapping pairs of labels down to none. Charts that were already narrow enough are unchanged

v3.89 · 22 August 2026

• Every calculator on this site has its maths checked by a separate program that works the same answers out independently. There are 54 of them. It turns out nothing was actually running them — and one had been failing
• What it had caught was real: the solar system page kept its own copy of the distance from the Earth to the Sun in two places, when that number is supposed to come from a single shared file. Copies like that drift apart. Fixed
• The unit converter’s table is now checked against its source — all 372 units, every conversion factor. Tested by deliberately corrupting one and confirming the check complains
• And a quieter one: a test that could not load one of its inputs had been reporting a warning and passing anyway, so the scientific calculator’s 77 worked examples had stopped being checked without anyone being told

v3.88 · 22 August 2026

• It said it cached rates for the day. It mostly did not. Rates were filed under the date the European Central Bank published them, and the page then looked for today’s date — which only matches after about 3pm on a working day, and never at a weekend. So it quietly re-downloaded on roughly three visits in four
• Now it remembers when it fetched, separately from when the rate was set. You still see the date the rate was published, because that is the one that tells you how fresh the number is
• The spread box no longer disagrees with the answer. Typing 50% left 50 on screen while the page worked in 20 — it is capped at 20. It now tells you it has capped you rather than changing what you typed
• And the rest checked out: 35 tests covering cross-rates, round trips and the real-cost panel. A flat £15 fee costs 15% of a £100 transfer and 0.15% of a £10,000 one, which is rather the point of that panel

v3.87 · 22 August 2026

• “Annual mean” needed explaining. Pick Beijing and it reads 75% humidity — higher than eleven of the twelve monthly figures on the same page, which average 57%. Both numbers are right, which is exactly why it needed saying
• Humidity is a percentage, and percentages do not average like temperatures. The muggy summer months hold most of the year’s moisture, so the year’s air taken as a whole is far damper than a typical month. Choosing it now explains itself, using the numbers for the city you picked
• The maths was left alone — it has to work this way for the annual point to sit in the middle of the loop the chart draws
• And the physics now has a test behind it: 56 checks against published vapour-pressure tables, wet-bulb values and the standard atmosphere. It passed nearly all of them first time; two of the failures turned out to be my expectations, not the calculator

v3.86 · 22 August 2026

• Everything that moves now moves the same way. Hovers, panels opening, the logo drawing itself — they had drifted onto a dozen different speeds and curves. The logo was even using a curve borrowed from Google’s design system rather than this site’s own
• The check meant to prevent that had a gap in it and had been letting 23 declarations through since it was written. Closed, then tested by deliberately breaking a page to make sure it actually complains
• Progress bars still move at a constant speed, and the slow background drifts still take as long as they take. Easing a progress bar would make it lie about how far along it is
• Tables now come from one place. Forty-five pages had reinvented the same table — 33 different cell paddings between them. The best version of it moved into the shared stylesheet, unchanged, so the pages using it look exactly as they did

v3.85 · 22 August 2026

• The formula on the page had four parts; the calculator only used three. It told you sweat loss was your weight change, plus what you drank, minus any urine passed — and then never asked about the last one
• One toilet stop is worth a fifth of the answer. A 400 mL void made the measured rate come out about 22% too high, which would have you planning every future session around drinking more than you need. There is now a box for it
• It does not change how dehydrated you got. That water left your body either way, so the percentage on the scales stays put. Log a void and the readout switches to show how much of the loss was actually sweat
• And two things spotted on screen: the default view used to say “another 0 mL would have kept you inside it”, and entering an impossible session showed a negative amount of sweat. Both fixed

v3.84 · 21 August 2026

• The page disagreed with itself. One panel drew an efficiency curve reading 94%; the panel beside it showed a primary current worked out as though the transformer were perfect. Both were on screen at the same time
• The current was understated by up to 12% on a small transformer at light load — and that is the figure you would use to size a fuse. It now divides by the efficiency at whatever load you have set
• You can now see where the power goes: the readouts show efficiency at your load and the input power, with the losses called out separately
• And it says what it leaves out — power factor, voltage droop under load, and the inrush at switch-on that makes transformer circuits need slow fuses

v3.83 · 21 August 2026

• Adding up your appliances is not the same as your bill. Most electricity contracts charge a fixed daily fee before you use a single unit — about 60p a day, £219 a year in the UK — and this page has never counted it
• It matters most to the people using least. That fixed fee is about a quarter of a typical bill and over a third of a small flat’s. For a very low user, switching to a tariff with a lower standing charge beats any amount of unplugging
• The appliance figures are averages, not plate ratings. A fridge is entered at 55 W, not the 150 W on its compressor, because it only runs about a third of the time. Worth knowing before you try to correct for it yourself
• And the carbon number is a yearly average — the real figure swings threefold across a day as wind and solar come and go, so when you run something matters more than which thing you run

v3.82 · 21 August 2026

• The Rule of 72 only works in the middle. Divide 72 by your interest rate for the doubling time — at 8% it is near enough perfect, at 2% it is a year long, and at 20% it is five months short. The error even changes direction, so you cannot correct for it. The page used to show only the case where it works
• And the reason it is 72 is that 72 divides nicely. The mathematically correct number is 69.3, which is worse at almost every rate people actually invest at — and impossible to divide in your head
• The projection itself checks out exactly against the standard textbook formulas — including the small gain from paying in on the 1st rather than the 30th, which is worth £2,511 over thirty years on £500 a month
• A quiet one about fees: the second 1% of charges costs you less than the first, because there is less left to take it from. Still about a quarter of the pot gone over thirty years for the first 1%

v3.81 · 21 August 2026

• Checked, and it came out clean. The charge time is worked out across the whole session rather than in one lump, so the slowdown as the battery fills is properly accounted for — and the power is capped by whichever is smaller, the charger or the car
• The claims on the page hold up. On a 60 kWh car at a 150 kW post, 80→100% really does take about as long as 10→80% — 21 minutes against 25. And a “60 kWh” fill really does bill you for 68
• Charging on rapids alone costs more per mile than petrol — about 1.5× a 45 mpg car. Charge at home overnight and it is a ninth of that

v3.80 · 21 August 2026

• Day and night are never equal at the equinox. It is the one thing everybody remembers, and it is wrong everywhere on Earth — the day wins by about 7 minutes at the equator and 13 near the Arctic Circle. The page had been repeating the rule without ever giving the number
• Two reasons, both geometry. Sunrise counts the first sliver of the sun, not its middle; and the atmosphere bends the light so you can see it while it is still below the horizon. The sunset you watch has technically already happened
• Add London’s longest and shortest days together and you get 24 hours and 28 minutes, not 24 hours. You are paid the same bonus twice
• The sunrise and sunset times themselves check out against published figures, and the page is now honest about where they get shaky — close to the poles, and for the moon, which is a simplified model here

v3.79 · 21 August 2026

• It used to say wind and humidity did nothing between 10 °C and 27 °C — which is most of the British year. Wind chill is not defined above 10, heat index not below 27, and in the gap the page simply handed back the air temperature
• A third formula now covers that band. At 12 °C, still and dry feels like 9 °C; windy and damp feels like 5. The chart shades the stretch neither official formula reaches, so you can see where each one hands over
• The sun switch works properly now. It used to add a flat 8 °C, and only when it was already hot. It now models radiation at any temperature, and eases off as the wind gets up
• Both original formulas were right all along — including two correction terms most versions of the heat index leave out. They are checked against the published charts, cell by cell

v3.78 · 21 August 2026

• The old tagline is back. “The numbers you keep looking up” is the line this site has carried longer than any other, and this is the third time it has been set. Settled by reading it out of all 253 archived homepages rather than from memory
• The opening paragraph stopped selling itself. Phrases like “worked out properly” and “honest about where it fails” have gone — they read as asking to be believed. The list of what is here does the job on its own
• And the odd one at the end is now the steak and the cold drink rather than how long a bearing lasts at 1,450 rpm. Same joke, but everybody has a freezer

v3.77 · 21 August 2026

• If you navigate by keyboard, you can now see where you are. The site had a focus outline, but almost every page was quietly overriding it — 90 of the 92 rules that could remove it did. It can no longer be removed
• Two diagrams were blank if you had motion turned off. They only ever drew themselves as part of an animation, so switching the animation off left an empty box. They now draw a still picture instead
• Everything that moves now moves the same way. The site had drifted to 22 different animation speeds; it now has four, and they were chosen from the ones that already felt right rather than by averaging
• Charts that have nothing to show yet now say so instead of presenting an empty frame
• Every control on all 101 tools was clicked, dragged and changed to check for errors. None found

v3.76 · 21 August 2026

• The estimator said a north-facing roof would beat a flat one. It cannot. The old calculation looked at the sun’s angle at midday only, and midday is the one moment that flatters a badly oriented panel — by noon it is still facing roughly the right way, even if it spends the rest of the day facing away
• Orientation had stopped mattering altogether past 90°. East, west and due north all returned the same answer. They now read 82%, 82% and 59% of a south-facing roof
• The orientation buttons never did anything. They were on the page, they looked clickable, and nothing was listening — which is exactly why the error survived. They work now
• And the rule everyone repeats is wrong. “Tilt your panels to your latitude” is too steep: the best angle is 41° in London and 31° in Phoenix. Cloudy skies want flatter panels, because scattered light comes from everywhere at once

v3.75 · 21 August 2026

• The weakest tool on the site, and its curve was wrong. It used one simple relation for every fluid, which is exact at the two temperatures it was given and drifts badly away from them — 83% low at −20 °C for a hydraulic oil. Cold is exactly where that number matters
• It now uses the right relation for each fluid: the petroleum industry’s own ASTM D341 for oils, a dedicated correlation for water (which fits nothing else), and a third for thin liquids like petrol and mercury
• It stops answering questions it cannot answer. Every fluid has a real temperature range now — the old version would happily tell you the viscosity of water at 150 °C
• New: Reynolds number and flow regime with a drawn pipe, side-by-side comparison, a sortable table of all 21 fluids, ISO grade and pumpability, °C/°F and kinematic/dynamic toggles — and you can type in your own oil’s datasheet figures and add it to the chart

v3.74 · 21 August 2026

• Twenty pages scrolled sideways on a phone. One CSS default was behind most of it: a column in a grid refuses to shrink below its widest unbreakable word, so a single long number could push a whole page off the screen. Invisible on a desktop, which is why it lasted
• Wide tables now all scroll inside their own frame instead of overhanging the page. Six of them never had one
• Corners and spacing follow a scale now. The site had been using eighteen different corner radii and forty-four different gaps — near enough every value from 1 to 20, twice over. They are twelve named steps, and nothing moved by more than two pixels
• Every change was checked by rendering all 101 pages before and after and comparing them element by element, rather than by reading the stylesheets

v3.73 · 21 August 2026

• The Thumbprint map was quietly missing an entire area. It kept its own hand-written list of areas and filtered through it, so Materials and Elements — and all four of its tools — never appeared on the map at all. It reads the real list now
• Its no-JavaScript list was 37 tools behind, and still filed the Materials tools under Mechanical and DIY. It is generated from the registry now, like every other fallback list on the site
• Eleven tools had drifted out of the field-notes pattern — six had none at all and five had them wearing the wrong styling. All eleven fixed, and the build now refuses to ship a tool without them
• Four chain steps were naming the wrong area, left behind when three tools moved into Materials and Elements
• The homepage cards showed three, four or five tools each, so the grid ragged on a phone. They all show four now, and the Materials card gets the colour and the background motif every other card already had

v3.72 · 21 August 2026

• A rocket nozzle in cross-section, coloured by speed, with the flow running through it. One slider — the pressure outside — takes it through every regime a nozzle can be in
• The rule that sounds wrong: to go faster than sound, the pipe has to get wider. Squeezing a hose speeds water up, and that stops being true above the speed of sound
• Watch a shock appear and march down the bell as you lower the pressure, then pop out of the exit and turn into diamonds
• And why engines are altitude-specific: a vacuum bell tears its own flow off the wall at sea level and makes a fraction of its thrust. That is why first stages fly small nozzles and upper stages fly enormous ones

v3.71 · 21 August 2026

• Relativity, built from one sentence: everybody measures light at the same speed. One slider at the top drives nine panels of consequences
• Watch a light clock slow down. A photon bouncing between two mirrors has to travel a diagonal once the clock is moving — and it cannot speed up to compensate. That is time dilation, and the next panel shows it is just Pythagoras
• See “at the same time” stop meaning anything. Lightning hits both ends of a train; watch from the platform and then from inside, and the two flashes swap order. Neither observer is wrong
• And the part you use every day. Satellite navigation gains 38 millionths of a second per day to relativity, and would drift 11 km daily without the correction
• Go to Andromeda in 28 years of your life — while two and a half million pass at home

v3.70 · 21 August 2026

• Two cars braking side by side on a road drawn to scale, with skid marks, brake lights and distance markers. Set the speed, the weather, the hill and how distracted the driver is
• The official Highway Code figures, taken apart. Work backwards from the table and it assumes a 0.67 second reaction and fairly modest brakes — a modern car in the dry beats it, and in the wet it does not
• The number that changes minds: a car doing 40 reaches the point where a 30 mph car had already stopped still doing 30. It has shed almost nothing
• And reaction is the half you can change. At 70 mph, reading a message costs 73 metres before the brakes are even touched

v3.69 · 21 August 2026

• Why Mars appears to go backwards. The loop that broke the geocentric model, drawn from the same two orbits already on the page — nothing reverses, Earth just overtakes it on the inside
• How far away it is right now, with the light delay, the radio round trip, and how long the drive would take. The answer swings by a factor of seven depending on where everyone is
• Your age and weight on every planet. A thirty-year-old is 124 on Mercury and has not had a birthday on Neptune
• The nearest and furthest points of the selected orbit are marked, so an ellipse looks like one
• On the periodic table, the head-to-head comparison now sits below the atom diagram

v3.68 · 19 August 2026

• A typing test that shows the measurement happening — every keystroke timed, the raw jagged signal drawn underneath the smooth one, and the smoothing under your control
• Three filters, and what each one costs you, in keystrokes. A moving average lags by half its window; a median is the only one a single long pause cannot move at all
• An honest unit. A “word” in any typing score is five characters, which is about 14% short of a real English one — so 60 wpm is really about 53 words a minute. Switch the text to code or numbers and watch the score change without you typing any differently
• Where it ranks, against a curve fitted to published figures — clearly labelled as fitted, not surveyed. Nothing you type is sent anywhere
• Which keys cost you, by median delay before each character

v3.67 · 19 August 2026

• Eighteen more molecules — petrol, acetone, vinegar, the CFC that ate the ozone layer, and a few deliberately strange shapes. Two of them show the shape rule failing badly: hydrogen sulfide should be bent like water and is 12° further over
• The drink cooling simulator now knows about drinks. It had been modelling one liquid whatever you picked. Eleven now — whisky chills in 130 minutes where water takes 161
• A head-to-head for the elements, like the one on the solar system page
• Planet compositions are readable — the colours were repeating and sitting lookalikes next to each other
• Twenty-one more strange units: bananas, buses, Nelson’s Column, a galactic year, a Scaramucci
• The egg sets from the outside in as it cooks, white before yolk
• The old homepage line is back, exactly as it was

v3.66 · 19 August 2026

• Every planet in 3D, on its real orbit — drag to turn the whole system, scroll to zoom, click a world to read it, and run time from a day a second to years a second
• See it at true scale, or compressed. Compressed is the version every textbook draws so the planets are visible. True scale is what it actually looks like, and the inner four vanish into the glare — which is the point
• Head to head on ten measures, eighteen worlds including eight moons, with each row won or lost and a running tally
• And where the physics gives up. The same sums that get the orbits right predict every planet’s temperature from its distance alone — and land 508 °C too cold on Venus, because they know nothing about air

v3.65 · 19 August 2026

• Three small helper functions had been written out separately in 227 places across the site — every copy identical. They are written once now
• Checked by rendering all 100 affected pages before and after and comparing every element, link and error on them. The only differences were a countdown timer, a clock, and the dice simulator, which are supposed to change

v3.64 · 19 August 2026

• Geostationary orbit was 7 km out. The orbital mechanics tool measured altitude from Earth’s average radius instead of its radius at the equator, which is what published orbital altitudes use — so it put geostationary at 35,793 km where every reference says 35,786. Fixed, and now checked automatically
• The checking scripts can now read the pages they check. Each tool’s maths is verified independently in Python, but nothing had ever compared that against the version running in your browser — which is how the steak timer and its own calculations disagreed for five releases
• Three tools wired up so far, with the count recorded so it can only go up

v3.63 · 19 August 2026

• The eleven area pages each carried their own copy of the same card design — 43 kB of one component, eleven times over. They share one file now, with each area’s colour set by a single line
• Which exposed a handful of small inconsistencies nobody intended: one footer spaced differently from the other ten, two breadcrumbs from the other nine, four hover effects left behind on an older style. All brought into line
• The build can now spot a component being copied before it spreads. It was tested against the site as it stood two releases ago, where it correctly finds both of the cases fixed this week

v3.62 · 19 August 2026

• The periodic table, fluid properties and the concrete mix calculator now live under Materials and Elements, which is the area they were already listed in. Every old link still works
• The vote button did nothing on 21 of the 96 tools — including the periodic table, molecules and SUVAT. Their names had never been added to the list the server checks against, so every vote and every count came back as an error. Found while checking the move above, and now fixed for all of them
• That list is no longer written by hand. It is built from the same catalogue as the rest of the site, so a new tool can never be left out of it again

v3.61 · 19 August 2026

• Every one of the 162 rule pages was carrying its own copy of the same stylesheet — 380 kB of identical CSS, sent 162 times and cached none. It is one shared file now, and the pages look exactly as they did: 39 elements and 19 properties each, compared before and after, zero differences
• The periodic table and molecule datasets now carry a version stamp in their filename. They were being sent with no caching instructions at all, which meant a corrected atomic weight had no guaranteed way of reaching anyone still holding an old copy

v3.60 · 19 August 2026

• Typing 4×4 into the search box now answers 16 instead of opening the graphing calculator. An x with a number on each side of it is a times sign — the way it is written on a tyre or a photo — while x²+1 and y=2x still open the plotter
• The calculator’s keypad no longer walks down the page as you type. It was moving 58 pixels between one line and nine, which is the worst thing a calculator can do. The worksheet now scrolls inside its own panel and the keys stay put
• The calculator is now checked against its own model on every build — 77 expressions and 19 things it must refuse, run through the real page. Two bugs were already hiding behind that one small change, including one that made 0x16 come out as zero
• The periodic table loads faster: 41 kB of element data was holding up the whole page before anything could be drawn

v3.59 · 19 August 2026

• Twenty-six molecules you can turn in 3D — water, methane, benzene, glucose, salt, diamond, and a buckyball built out of the golden ratio
• None of the shapes are stored. Each molecule is just a list of what is bonded to what, and the shape is worked out by letting the electron pairs push each other apart until they stop moving. Methane comes out at exactly 109.47° without that number appearing anywhere
• And where that rule fails, the page says by how much. Water should be 109.47° by the same reasoning and is really 104.5°, because a lone pair is fatter than a bond — every molecule shows the size of the miss
• It shares the periodic table’s data, so a molar mass here and an atomic weight there can never disagree — and each element’s compound list now links straight into the 3D view

v3.58 · 19 August 2026

• New area: Materials and Elements — the periodic table, fluid properties and the concrete mix calculator, together. What things are made of and how they behave
• Physics Simulation is now just Physics
• Searching “calculator” now finds the calculator. Seventy tools have “Calculator” in the name, so the word told the ranking nothing — it now weighs how much of a tool’s name your words account for, which also fixed “subnet”, “tip”, “mortgage” and “bmi”
• On phones the floating buttons no longer sit on top of the page heading as you scroll
• The search page gained proper autocomplete — questions it can answer outright, then tools, then areas, all keyboard-driven — and lost the decorative squiggles on the tool cards, which were shaped like data but meant nothing

v3.57 · 19 August 2026

• The calculator was crammed into a narrow side column while the explanation of how it works took the middle of the screen. It now fills the width, with the worksheet on the left and the answer and keypad beside it, and every word of explanation moved below
• On a phone the keypad was about twelve hundred pixels below the worksheet, and each answer was squeezed into four pixels of width. Now the answer comes first, then the worksheet, then the keys — and the results sit under each line where you can read them

v3.56 · 19 August 2026

• Work down the page instead of on one line. Give a value a name and every line below can use it — change the first line and the whole sheet re-runs. Nothing disappears, so you can check the working rather than trust a number you can no longer see
• Fifty functions and constants, including combinations and permutations, highest common factor, logs to any base, list averages, hexadecimal and binary in and out, and the physical constants an engineering answer usually needs. Every one has a worked example you can tap
• Searching a sum now opens the calculator, not the graph plotter. And typing something that really is a curve — like x²+1 — now opens the plotter, which previously returned nothing at all

v3.55 · 19 August 2026

• A proper calculator — full keypad, memory, a tape of everything you have worked out, degrees and radians, and keyboard entry. Ninety-four calculators on this site and not one of them was a calculator
• It shows you how it read what you typed. Type 2+3×4 and underneath the answer it prints 2 + (3 × 4), so you can see it grouped the sum the way you meant before you trust the 14
• It tells you the truth about 0.1 + 0.2. Computers cannot hold a tenth exactly, so the answer is really 0.30000000000000004 — most calculators round that away, this one shows you when the stored number differs from the one on screen
• Nonsense is refused rather than guessed at, and the maths is checked against a second implementation written from scratch: 39 expressions that both have to agree on, to the last digit

v3.54 · 19 August 2026

• The new “Found” section on the periodic table was unstyled — it had been written using a panel style that does not exist on this site, so it rendered as bare text between two proper panels. It now matches everything around it
• The build now catches this automatically. If any element is given a style name that no stylesheet defines and no code uses, the build stops — because an unknown style name is not an error in a browser, it just quietly does nothing and the page looks almost right
• Turning the check on found 37 more style names already in the site that do nothing at all. They are recorded so they can be cleared up, and so the list cannot grow

v3.53 · 19 August 2026

• Every element now shows its electron configuration, what state it is in at room temperature, when it was found, who found it, and what its name means — cobalt after the goblin miners blamed for poisoning them, argon after the Greek for “idle”, gallium named for France and as a pun on the man who found it
• Drag a year and watch the table fill up in the order people worked it out. Eleven elements by 1250, thirty-four by 1800, eighty-three by 1900 — then a whole corner that nobody found at all, because it had to be built
• First ionisation energy joins the properties you can rank and colour the table by. It is the sharpest pattern on the whole chart
• The configuration and the state are worked out from the physics rather than copied, and checked against the shell counts the page already had — which caught three mistakes before they shipped, including one that would have listed flerovium as a room-temperature liquid on the strength of a prediction

v3.52 · 19 August 2026

• Type a question and the answer appears as you type — no button. “300k mortgage at 4.5% over 25 years” gives you £1,667 a month; “paint for a 4×5 room” gives you 39.9 m² and four tins. The calculator underneath is already filled in
• The page used to open with all 94 tools stacked at full size — nearly six thousand pixels of them, with the search box a third of the way down. Now there is one field in the middle of the screen and a dozen suggestions around it
• Hovering a tool shows you what it looks like before you open it
• The old tagline is back — “free, browser-based calculators for the numbers people reach for again and again”

v3.51 · 18 August 2026

• Fifteen more rules show the gap between the shortcut and the real answer — 41 of them now do. The pick of them: braking distance really does go as the square of speed, but stopping distance does not, because first you have to notice — and at 20 km/h more than half the tarmac you use is spent still deciding
• The remaining 119 rules each got a reason rather than a to-do. Thirty-five of them are simply correct — there is nothing to draw. Thirty-four have no number in them. Thirty-one are chosen limits rather than estimates. Only nine are still genuinely worth doing, and each says what it needs
• Along the way: “boiling point drops 1 °C every 300 m” was checked and is right to a thirtieth of a per cent, and one new chart shipped with its explanation backwards until the numbers were run again

v3.50 · 18 August 2026

• Eight more rules now show the gap between the shortcut and the real answer — the bolt-torque rule, ramps, pipe sizing, spring rates, tap drills, sample sizes, settling time and Bode plots
• Four of them are outside their own tolerance at exactly the value people use, and the page now says so in those words. The bolt one matters most: torque to the usual rule on a lubricated thread and you put about 60% more tension in the bolt than you meant to
• One rule was taken off the list because it turned out to be right. “Boiling point drops 1 °C every 300 m” is accurate to a thirtieth of a per cent up to 4,000 m — drawing an error bar on it would have been theatre
• Housekeeping: the internal to-do list said it covered 131 rules when the site has 160, and another note claimed 27 pages ignored the reduced-motion setting long after they had all been fixed. Both now count themselves instead of being typed

v3.49 · 18 August 2026

• The steak timer now models the steam coming off a resting steak. Meat keeps losing water long after the surface has dried, and that carries real heat away — the rest had no way to lose it. Set so the steak loses the 1–2% of its weight a real one does
• The thickest steaks the page offers were returning no answer at all. Anything from about 50 mm up was told it would never reach temperature, when it would have been ready in 25–35 minutes. Every thickness on the slider now works
• A thin steak cools while it rests rather than carrying on cooking — an 8 mm one drops about 2 °C, so you take it out above the temperature you want. A thick one gains more than twenty. The page no longer pretends carryover is a single number
• Honest note: adding the steam was worth about two degrees, not the whole difference between this page and the usual published carryover figure. That difference is real, and it is because a hard sear is a harder cook — both numbers are shown side by side

v3.48 · 18 August 2026

• The steak timer told you to pull at one temperature and cooked to another. Four places on the page still quoted a carryover figure the calculation stopped using five releases ago — including the worked example, which claimed a pull temperature and a time the tool had not produced since. All now show what it actually does
• The moment to take it out was being searched for badly and could miss by nearly two degrees on a thin steak — enough to matter when five degrees is a whole doneness. It is now solved exactly; the worst error across six thicknesses is three hundredths of a degree
• The page now shows both carryover figures side by side, because they genuinely disagree and both are right — the usual published number is measured on a gentle cook, and a hard sear on cast iron behaves very differently
• Dice were clipping into each other on about one roll in six. They were kept apart as though they were round; a landed die is a square that can point any way. Now separated by the shape they actually cover — and dice that do not need the space no longer take it
• Behind the scenes: the independent check that is supposed to catch mistakes in the steak maths had drifted away from the page over five releases. It now reads the page directly, so it cannot drift again without failing

v3.47 · 18 August 2026

• Every element now lists five real uses instead of three, and five compounds you might actually meet it in — iron as rust, magnetite, pyrite, siderite and iron sulfate, with the formulas written properly
• The twenty-six elements with no compound each say why not, and the reasons are different: a noble gas has nothing to gain by bonding, while astatine and the superheavies only ever exist a few atoms at a time. Radon is both — and the only one of the twenty-six anybody is actually exposed to
• All 826 new entries were checked before they reached the page, including one check asking whether each compound really contains the element it is listed under

v3.46 · 17 August 2026

• The field-note cards were laid out wrong on three pages — they were using a container that does not exist in the stylesheet, so they stacked full width instead of sitting in a grid. Fixed on the periodic table, the gym tool and the dice roller
• The atom now says what is in it — protons, neutrons, electrons and shells in the corner, and a key naming what each colour of sphere is
• The pattern panel and the ranking bars now show the same five properties in the same order, and name the element in full rather than just its symbol

v3.45 · 17 August 2026

• The table was supposed to be colour-coded by element type and was not — every one of the 118 cells was rendering in the same colour. Fixed, and each category now has its own shade
• The atom is half again as large, with a glow behind the nucleus and a halo on every electron so the shells read clearly
• The flat view is properly flat now instead of a tilted version of the 3D one
• Every element as a sortable list — tap any column to rank all 118 by mass, density, melting point or size, with totals underneath

v3.44 · 17 August 2026

• All 118 elements, with a 3D atom you can spin — the nucleus sized by how many particles are in it, and the electron shells drawn from the real occupancies
• Three genuine uses for every single element, and every property shown as a position among all the others rather than a number on its own
• Colour the whole table by a trend and watch the pattern appear in the layout
• Plus the things a wall chart leaves out: the four places the atomic weights run backwards, why argon stops at eight electrons and not eighteen, why atoms get smaller as you go right, and the one element that never melts

v3.43 · 17 August 2026

• The spots were being drawn as perfect circles, which is why they still looked like beads sitting in front of the dice — a round dot on a face turned away from you cannot be painted on it. They are part of the face now, so they squash and tilt with it, and they darken on the shaded sides like everything else

v3.42 · 17 August 2026

• The spots looked like beads glued to the dice. They were being drawn floating above the surface and lit like little spheres. They are drilled into the face now, the way a real die is made
• Rolling two dice only ever showed one. The second was being thrown from the edge of the table and travelling further off it. Both stay on the felt now
• The dice were sinking into the table and passing through it as they tumbled. They sit on it properly, whether flat on a face or balanced on a corner

v3.41 · 17 August 2026

• The dice looked see-through. The faces were being drawn in the wrong order, so the back of each die was painted over its front. They are solid now, with the spots on the faces you can actually see
• They bounce properly. They were being dropped gently, so they hit the table and stopped. They are thrown down now and rebound several times before settling
• Each die still carries its value above it, so the result is unmistakable

v3.40 · 17 August 2026

• The dice were showing you their underside. The camera was set up below the table looking upward, so the spots were painted on the faces pointing away from you and the face you could see was blank. That is why the numbers were unreadable
• The spots were also being covered over by whichever face was drawn next. They are now drawn on top of everything, after the dice themselves
• The view looks further down onto the table, the dice are larger, they no longer land on top of each other, and each one carries its value above it
• A tossed coin flips end over end now, thrown upward, rather than tumbling in every direction at once

v3.39 · 17 August 2026

• The dice are thrown now — they fall, bounce, tumble and come to rest on a table, with the spin knocked about on each bounce, instead of a flat shape rotating to the answer. The coin is properly flipped and lands
• The number is still decided by the browser’s cryptographic random source, not by the bouncing. The throw is shown landing on a result already drawn — deliberately, because if the tumble decided it the odds would come from the animation instead, and the fairness test on the same page would be testing the wrong thing. The page explains this
• The animation stops the instant the dice settle, so leaving the page open costs nothing

v3.38 · 17 August 2026

• A four-step walk from deciding to train to a first session — what the scale actually tells you, what you burn in a day, what weight belongs on the bar, and how hard the easy days should feel
• It is honest that the number you start with, BMI, is the first one to stop trusting: once you are lifting it moves for reasons that have nothing to do with whether it is working

v3.37 · 17 August 2026

• Tell it your height, weight, experience, what you are training for and how long you have, and it builds the session — including sensible starting weights worked out from your bodyweight, rounded to something you can actually load on a bar
• It respects the time you gave it. Twenty-five minutes gets seven exercises, ninety gets twelve, and the big lifts are always kept first
• Or press Surprise me for a balanced session across the whole body. It shows you the seed, so the same one gives you the same workout again
• The defaults still work without filling any of it in

v3.36 · 17 August 2026

• The demonstration and the session list were both blank. Two leftover lines from yesterday’s rebuild referred to something that had been deleted, which threw an error every time the page tried to draw — and because the list is built straight after the figure, it never got there either
• Fixed, and the automated checks now actually try to draw each exercise rather than only testing the maths behind it. That is why this slipped through with every check passing

v3.35 · 17 August 2026

• The figure has muscle now. Arms and legs are rounded and thicken where a limb actually thickens — a biceps, a calf — instead of being rectangular blocks, and there are hands, a proper head, shoulders and a waist
• The plank was floating above the floor. A plank rests on the forearms and the toes, and nothing was checking that. Every exercise is now tested for what is actually touching the ground — which also caught a bench press sitting below the floor entirely
• Rest can wait for you. Either the timer counts you back in, or it banks the set and does nothing until you tap — useful when the rack is still busy

v3.34 · 17 August 2026

• It would have fallen over. The weight of the body and the bar together sat well outside the feet on the squat, the deadlift and the row. Every major body part is now treated as a real mass, the bar included, and the figure leans over its feet until the whole lot is balanced — which is exactly what you do without thinking about it
• The feet no longer slide across the floor. A foot on the ground stays put and the body moves instead — except in the split squat and the carry, where stepping is the point
• Fuller bodies — chest, shoulders, waist, hips and thighs, shaped differently for the male and female figures rather than one figure scaled up and down

v3.33 · 17 August 2026

• Every exercise is now checked automatically for joints bending the wrong way or further than a joint can go — all fourteen movements, both body types, right through the movement rather than just at the ends. It found a row that wrenched the shoulder and six exercises whose feet floated off the floor
• The feet stay on the ground. The hips drop in a squat because the knees bend, which is how it actually works
• A bigger figure, and dragging turns it the right way — it was backwards
• The session is a numbered list you read top to bottom, with a small preview of the exercise coming next
• Light, Average or Heavy — the same workout at the effort you want

v3.32 · 17 August 2026

• The picture was running nearly a minute behind the countdown by the end of a cook, which is why the steak appeared to turn over at the wrong moment. It now follows the clock exactly
• It was redrawing the whole simulation sixty times a second to show a picture that only changes about once a second. That is why it struggled on slower phones. It now redraws only when there is something new to show
• Dragging the timeline is smoother for the same reason
• The comparison table has room to breathe — bigger type, taller rows, and the row under your cursor lights up

v3.31 · 16 August 2026

• Arms and legs were bending the wrong way. Knees folded forwards and arms swung behind the body, because three joints each used a different sign for the same thing. There is one rule now and every exercise was rebuilt against it
• Knees and elbows can no longer bend backwards at all — they are clamped, the way a real joint is
• There is a floor. The figure stands on a grid you can orbit around, so you can tell a forward lean from a camera angle
• Each exercise sits properly in space: bench press on its back with feet down, plank face down on the forearms, lunge with the back leg trailing

v3.30 · 16 August 2026

• The demonstration is now a real 3D figure you can drag to spin and scroll to zoom, instead of a flat drawing that only looked right from the front
• The old figure was genuinely wrong — the maths joining one limb to the next was incorrect, which splayed the arms and legs out and made a squat look like someone lying down. Rebuilt properly, so it stands up and moves like the lift it is showing
• Each exercise sits where it belongs: a bench press lies on a bench, a pull-up hangs from a bar, a plank is on the floor
• Save as many routines as you like, by name, and load or delete them whenever

v3.29 · 16 August 2026

• An animated figure demonstrates every exercise — squatting, pressing, rowing, hinging — with the barbell or dumbbells drawn in its hands, and a male or female figure to choose between
• The whole routine as a timeline across the top, each block sized by how many sets it is, filling in as you finish them. Tap any block to jump to that exercise
• A proper progress bar, with the rest period sweeping through it so you can see how far through the rest and how far through the session you are at once
• The animation stops when you scroll past it or switch tabs, and holds still if you have asked your device to reduce motion

v3.28 · 16 August 2026

• Six ready-made routines, or build your own from 44 exercises — and add your own lift if it is not in the list
• A rest timer that actually beeps, counting you back in at three, two, one, with the rest length set by what the set is for: three minutes for heavy strength work, ninety seconds for muscle building
• Set-by-set tracking with a body map showing which muscles each lift works, and your running volume for the session. Space bar marks a set done
• Underneath: your estimated one-rep max from three formulas at once, and exactly which plates to put on each side of the bar
• Everything you add stays on your device — no account, and the page never contacts a server

v3.27 · 16 August 2026

• Rolling is now the whole top of the page — one die, two dice, one coin or two coins, and a Roll button. Everything else moved into two panels you can open if you want them
• The buttons look like the rest of the site again. The main Roll button was rendering dark-on-dark because the page never set its colour
• Tossing a coin said “2”. It says HEADS or TAILS

v3.26 · 16 August 2026

• Roll d4 to d100 or flip coins as real 3D objects — the six-sided die is an actual rotating cube — with the exact odds of every outcome drawn behind the rolls you actually got, worked out properly rather than estimated by rolling
• Advantage is worth nothing at the extremes and +25 points in the middle, which is not the flat bonus most people assume it is
• Four dice where each one beats the next, round in a circle — so there is no best die, and the one with the lowest average still wins two times in three
• A second pair of dice, numbered completely differently, that gives identical odds to an ordinary pair
• Plus why a run of six heads is the ordinary case rather than evidence of anything, and a real fairness test on your own rolls

v3.25 · 16 August 2026

• The page opens about four times faster and responds far more quickly when you change a city. It was building the world map, the zone browser and the market board every single time you touched a control — thousands of items, all of them further down the page than you had scrolled
• Those views are now drawn when you get to them. Everything shows exactly what it showed before

v3.24 · 15 August 2026

• Every page starts drawing sooner. The one script that has to run before anything appears was two thirds a list of tools that nothing needed that early — it now loads out of the way, and the blocking part is a third of the size
• The text arrives faster, because the fonts are now requested at the same moment as everything else instead of waiting for the stylesheet to be read first
• The Rulebook paints before its data loads rather than after — 157 kB used to hold up the entire page
• Long pages scroll and resize far more smoothly. The Rulebook is 26 screens and the changelog 87, and the browser was re-measuring every screen each time anything changed — including the moment a font loads. It now only does the part you can see

v3.23 · 15 August 2026

• The page now loads in about a third of the time and uses a tenth of the memory, which matters most on a phone — it was heavy enough that a phone could throw the page away while you were cooking. The cooking times are unchanged
• The picture of the steak is properly smooth. The bands of doneness now curve the way heat really moves through the meat, instead of stepping through little squares
• The comparison table waits until you scroll to it rather than being worked out before you can use anything — it was the single slowest thing on the page
• Weight is now in ounces, with grams in brackets
• Fixed the small print, which claimed the tool ignores the crust and the water boiling off the surface. It has taken both into account since August

v3.22 · 15 August 2026

• The site logo was appearing down the side of the steak timer and pushing the whole page across, because the header at the top of the page was never properly closed — so everything on the page was technically sitting inside the logo block. Spotted by a reader; it had been that way since the tool was built
• The small print at the bottom was still describing the egg timer, down to yolk temperatures and the shape of an egg. It now explains how the steak simulation actually works
• The build now refuses to publish a page whose layout tags do not close properly, so this cannot happen again unnoticed — the other 283 pages were checked and are fine

v3.21 · 13 August 2026

• The timeline is now banded by which side of the steak is on the pan, in the same two colours the picture uses, so you can see at a glance which face is cooking
• A second bar shows how far through the cooking you are rather than how far through the time — they are not the same thing, because the middle of a steak barely moves for the first few minutes and then climbs quickly
• That bar carries on past 100%, because going too far is the mistake worth seeing coming

v3.20 · 13 August 2026

• The doneness colours used to run backwards as a side cooled after being turned — well done sliding back to medium rare, twice a minute. Cooking is a permanent change to the meat: once a part of the steak has been to a temperature, it stays that cooked even as it cools
• The picture now tracks the hottest each part has ever been, so the doneness can only ever move forwards. The temperature view still shows it cooling, because that part is real
• Spotted by a reader, and it had been wrong since the tool was built

v3.19 · 13 August 2026

• The picture keeps going through the resting stage instead of freezing the moment the steak comes out of the pan — and the steak sits on a plate while it rests
• It counts down to the right thing. Near the end it now says “take it out now” rather than telling you to turn a steak that should already be on a plate
• The steak is drawn to scale. A thick one looks thick and a big one looks wide, instead of every steak being the same rectangle
• The simulation runs at nearly four times the detail, and the flip animation now actually plays

v3.18 · 13 August 2026

• It now works backwards from how you want it when you cut it. The tool finds the moment to take the steak out so that after the whole rest the middle is exactly where you asked — so the temperature it tells you to pull at is well below the doneness you chose, on purpose
• A browned crust insulates the steak, and that was missing from the simulation. Add it and the surface sits at a realistic searing temperature and far less of the inside overcooks
• Every doneness band now shows from the start rather than appearing part-way through, the steak visibly turns over, and it spends a few seconds off the heat each time you flip it — as it would in a real kitchen

v3.17 · 13 August 2026

• The resting steak was still shown sitting on the hot pan. It now rests on a warm plate, off the heat
• The resting view stops when the steak is ready to serve rather than carrying on past it
• The page is candid that a thick steak seared hard really does end up with a wide band of more-cooked meat around a pink middle. That is not a flaw in the calculation — it is why people reverse-sear thick steaks

v3.16 · 13 August 2026

• The steak page had an egg as its icon. It was built using the egg timer page as a template and that little detail came along unnoticed. It now has a steak
• The clock sits with the progress bar it drives, and the advice about how often to turn the steak sits with the control for it — rather than both being somewhere further down the page
• The numbers you act on are grouped at the top, with the supporting detail folded away

v3.15 · 13 August 2026

• Most of a hot pan’s energy goes into boiling water out of the steak, not into heating it. That was barely modelled, which made the outside of the simulated steak far hotter than a real one. Now it is modelled properly — though the page is candid that one related figure is still too high, and says why
• The flip animation was turning the whole picture over, pan and labels included. Now only the steak turns
• It tells you how often to turn it, and shows its working — the same calculation run at each cadence, so you can see that turning often gets there sooner and leaves more of the inside at the doneness you wanted

v3.14 · 13 August 2026

• The cross-section was drawn upside down — the side against the pan appeared to be the side in the air. Fixed, and checked in both directions this time
• The resting stage is now simulated too. Drag past the moment you take it out and you can watch the heat move from the hot outside into the cool middle, which is what resting actually does
• It now tells you where you are against where you are going — “currently blue, target is medium rare” — colours the two faces so a flip is obvious, and puts the four numbers you act on together with the rest tucked away
• Added a room-temperature starting option

v3.13 · 13 August 2026

• A new steak calculator and timer. Pick the cut, how thick it is and how you want it done, and it works out the time by actually simulating the heat moving through the meat — then times the cook for you, telling you when to turn it, when to take it out and how long to rest it
• Thickness is what matters, not weight. A 40 mm steak takes well over twice as long as a 25 mm one; making the same steak heavier at the same thickness changes almost nothing. Every recipe quotes the wrong number
• You can watch a cross-section of the steak cook, drag back and forth through the cook, switch between a temperature scale and a doneness scale, and flip it manually if you would rather judge it yourself

v3.12 · 13 August 2026

• Carve a network into unequal subnets. Type the sizes you need — 50 desks, 20 phones, a pair of router interfaces — and it lays them out on the boundaries each one has to start on
• Collapse several networks into one route, and be told plainly when that route also covers addresses you did not list. Two networks can sit next to each other and still not combine, which is a genuinely easy way to take somebody else’s traffic by accident
• Two-device subnets get a /30 rather than a /31 — a /31 works only between two routers, not on a network with a gateway on it

v3.11 · 13 August 2026

• The build now refuses a page that names two elements the same thing. The previous release shipped exactly that mistake and every check passed — the sort of fault that leaves a page looking right while one of its numbers quietly stops updating
• The new check was tested by deliberately re-creating the fault and confirming the build rejected it, rather than by writing it and watching it pass

v3.10 · 13 August 2026

• Every max-heart-rate formula is about 10 beats out for any given person. The page used to argue about which formula to use — a difference of about 5 beats at 40 — while saying nothing about the bigger gap. It now shows the range you actually sit in
• That range is wider than a training zone. At 40, “your max is 180” really means somewhere between 160 and 200, so the top of zone 2 could be anywhere from 112 to 140 bpm. Use it as a guide and go by how hard it feels
• If the zones matter to you, the page now says plainly: measure a threshold instead of estimating a maximum

v3.9 · 13 August 2026

• You can now type in the results you actually got and get a straight answer — including the range the true effect could be in, which matters more than the yes/no
• “Not significant” does not mean “no difference”. The tool now says so with your own numbers: a result that looks like nothing can still be hiding a 12% win the test was too small to see
• Testing several variants at once multiplies your chance of a false winner — four of them is an 18.5% chance, not 5%. There is now a slider for it, and a corrected threshold

v3.8 · 13 August 2026

• It used to reward you for using a symbol. Now it works out how an attacker would actually find your password. P@ssw0rd1! went from “66 bits” to 21 — cracked instantly — and the page tells you why: it is the word “password” with letters swapped
• You can see how much the website matters. The same password is instant to crack if a site stored it badly and takes millions of years if stored well. That is the part you cannot control, and it is now visible
• Four words from a dictionary still beat a short password full of symbols — and the page now scores those words honestly rather than flattering them
• Nothing you type is sent anywhere. It never was, and still is not

v3.7 · 13 August 2026

• Styling repeated on all 153 rule pages now loads once and is cached, making those pages smaller on every visit
• A larger version of the same change was tried first and reverted: it would have quietly altered spacing on 92 other pages. Everything renders exactly as it did before

v3.6 · 13 August 2026

• Updating the tool list no longer makes your browser re-download the whole site script. The list of calculators moved into a smaller file that changes on its own, so a routine update now costs about a quarter of what it did

v3.5 · 13 August 2026

• The answer bar understands a lot more of what people actually type. It went from 16 phrasings to 35 — “can I afford a 280k house on 45k”, “what size breaker for a 3kW heater”, “bmi for 5 foot 10 and 13 stone”, “take-home on 45k”, “how many tins for my lounge” and more
• Where the answer depends on tax rules or published tables, the bar opens the calculator instead of answering. Those numbers change, and one copy of them is safer than two
• The mortgage calculator now opens in your own market. It always started in the United States, in dollars, over 30 years. A UK visitor now lands on pounds and a 25-year term. A link somebody shared with you still opens exactly as they left it
• Questions the bar cannot answer are noted in your own browser only, so the next batch of phrasings is chosen from what people really asked. Nothing is sent anywhere

v3.4 · 13 August 2026

• We went looking for more of the bug we fixed last time. The wire gauge chart had been drawing a number that disagreed with the number printed beside it. Every calculator on the site was scanned for the same fault — a figure worked out twice, two different ways — and no second case was found. The scan is kept so it can be re-run whenever a new chart is added
• The motor starting calculator now has an independent check behind it, like every other tool here. Its maths held up; its numbers are still typical values rather than your motor’s, and the page says so

Nothing on the site changed this release. That is the result, not an omission.

v3.3 · 13 August 2026

• The "what changed in this tool" list at the foot of every tool page was four months out of date, and fourteen tools said nothing had ever changed — four of which had been built the week before. It is now rebuilt from the archived copies on every release, and the build fails if it falls behind
• A voltage-drop chart could disagree with its own headline number. On the wire gauge tool, picking metric and then switching back to AWG left the chart reading distances in the wrong unit — drawing about a third of the real voltage drop. The number beside it was always right; the graph is now right too
• Every safety-critical calculator now says what its numbers rest on — whether that is a published standard or, honestly, a representative value
• Pages load faster on a second visit. The shared code and styles used to be re-checked with the server on every single page view; they are now named after their own contents, so your browser can keep them

v3.2 · 10 August 2026

• The counts were wrong in three places. The About page claimed 115 archived versions when there are 192, and 150 source citations when there are 211; a project file still said 86 tools. All corrected — and the build now refuses to complete if any count anywhere disagrees with the real one
• The archive count was one release behind, on every release. It was counted from the folders on disk, but a version's folder is only created after the site is built — so the number was always missing the release it shipped with
• The link preview image said "51 calculators" and cropped its own title. It is redrawn from the live figures on every build, so it cannot go stale again
• Three tools had no link preview at all, so sharing them showed a bare URL. Fixed, with a check that every page carries one
• A clearer name on the door: "calculators that show where the shortcut fails"
• The rule of the day now appears in the page itself rather than only after JavaScript runs — search engines were seeing a placeholder

v3.1 · 10 August 2026

• Rows above your refresh rate now line up exactly, as they always should have. They were being animated in a way that made them disagree slightly — which made the boundary you are meant to read much harder to see
• A second way to read it: "same pixels per frame". Each row moves further per second than the one below until it runs out of frames, so the speeds stop increasing at your refresh rate — often easier to spot than the stepping
• The ladder now goes down to 1 Hz, which makes what it is doing unmistakable
• Pursuit compares five different rates side by side — 24, 30, 60, 120 and 240 Hz — instead of showing the same thing three times

v3.0 · 10 August 2026

• A stutter ladder on the refresh rate page. Seventeen rows all moving at the same speed, each limited to its own rate — the slow ones visibly step, and the lowest row that looks smooth is your display's refresh rate
• The measured number is drawn onto the ladder, so you can see whether the measurement and your own eyes agree
• A pursuit pattern for judging motion clarity by tracking a moving block, and a tearing illustration showing what a torn frame looks like
• It explains judder honestly: above your refresh rate a row is only perfectly smooth when its rate divides into yours — which is exactly why 24 fps film stutters on a 60 Hz screen

v2.9 · 10 August 2026

• New tool: Screen Refresh Rate Test. Measures what your browser is actually presenting at — 60 Hz, 144, 240, 360, 480, 500 and beyond
• It copes with dropped frames. A stutter during the test would fool a simple average into reporting a rate no monitor is sold at; this reports the real rate and counts the dropped frames separately
• Frame times, jitter and 1% lows, with a chart of every interval and a timeline of the run — a high average with a poor 1% low is what stutter actually feels like
• It says "variable" when your display is variable rather than inventing an average, and tells you when a result looks disturbed rather than presenting it as fact

v2.8 · 10 August 2026

• New tool: Refraction & Diffraction. Snell's law with a live ray diagram, critical angle, how much light reflects and Brewster's angle — plus single-slit, double-slit, grating and circular-aperture patterns drawn out
• The room visualiser now works on phones. It was demanding a graphics feature a lot of mobile hardware does not have, and its internals could overflow on the format that remains. Both fixed, with settings picked to suit a small screen
• The unit converter's scale labels no longer overlap — they are turned on their side, so they stay readable however tightly the reference points bunch up
• You can now limit significant figures or decimal places in the converter. Both are off by default: full precision unless you ask for less
• Tap tempo averages properly. It used to forget taps after 2.5 seconds, so slow tempos never got a decent average. It now keeps up to 32 taps and shows how steady you were

v2.7 · 10 August 2026

• Every piece of furniture can be switched off — one at a time, or the whole room at once if you want to see the paint on its own
• The rooms are bigger, apart from the small one, which was about right. Each is also more distinctly itself: the office has a monitor and drawers, the kitchen has stools and a fridge, the bathroom has a mirror and a towel rail
• Furniture is built from several parts now, so a sofa has a back and arms rather than being one block
• The sheen table was rendering as unstyled text — it now uses the same reference table as the rest of the site, and the sections are in the usual order
• The colour picker's boundary is a smooth curve instead of a stepped line, and is drawn as two lines: the edge of what paint can mix is a transition, not a cliff

v2.6 · 10 August 2026

• The page now ends with a footer like every other tool on the site — it was simply missing
• The field notes are in proper cards again. They had been marked up with styles that did not exist anywhere in the project, so they were rendering as loose text
• Render quality now goes up to 10,000 samples, for when you want a clean image to save rather than a quick look

v2.5 · 10 August 2026

• The room has its trimmings now — skirting boards, coving, window reveals and framed artwork, all paintable in their own colour and sheen
• The floor looks like a floor: real board widths with staggered joints and per-board tone, or a grout grid if you pick tiles
• A ceiling light you can switch on, with a warmth slider from candle-warm to daylight-white — and it casts proper soft shadows
• Pick an accent wall in a second colour from your saved list
• Small, medium and large rooms. Try the same colour in each — it reads stronger in the small one, because the walls are closer and the light bounces more
• You choose the render quality — up to 1000 samples and 1152×720 — and can save the result as a JPG
• The colour picker's hatching is much finer and lighter, so you can see the colours underneath it clearly

v2.4 · 10 August 2026

• The area paint cannot reach is now marked with fine diagonal hatching instead of being darkened. You can still see the actual colour underneath — which matters, because shading a swatch changes the colour you are trying to judge
• The boundary line is smooth rather than stepped
• Two errors it uncovered are fixed. A boundary was being drawn around pure white and around black — both colours the palette obviously produces — and the palest tints were missing from the model, which made very pale colours look unreachable

v2.3 · 10 August 2026

• A new tool: the Room Colour Visualiser. Pick a room, paint the walls and ceiling with colours you mixed, choose a floor, and look around a proper 3D preview
• The light actually bounces. A strong wall colour tints the ceiling and the far wall — the main reason a colour feels different once the whole room is done, and the thing a flat swatch cannot show you
• Sheen is real, not a label. Matt through gloss changes how the surface reflects, so a gloss wall shows a sharp reflection of the window and a matt one does not
• Six rooms, four kinds of daylight, six floors — living room, office, kitchen, bedroom, bathroom and hallway
• The mixing page now has 26 tubes and a library of 62 named decorating shades — sage, greige, navy, terracotta and the rest — searchable, and each one comes with the closest mix the palette can manage
• Save colours you like and they appear in the room visualiser
• The colour picker now shows you what paint can actually reach, shading out the colours no mix will match

v2.2 · 10 August 2026

• Two of the fourteen tubes were the wrong colour. Phthalo Green rendered as a pale yellow-green and Sap Green as a yellow, so nothing in the palette pointed green — ask for a mid green and the tool suggested blue mixed with black
• Every tube has been refitted so its swatch matches the real pigment, while still mixing the way paint does: yellow and blue make a green, red and yellow make an orange, complements still mix toward mud
• Match quality was being graded on the wrong scale, so nearly every result was labelled with the most pessimistic wording available even when it was a good match. A close match now says so

v2.1 · 10 August 2026

• A proper colour picker on the paint tool — drag a saturation/value field or a hue rail, or use your system picker
• Six live colour codes — hex, RGB, HSL, HSV, CMYK and Lab. Type into any of them and the rest follow, with lightness, chroma and contrast shown alongside
• It now tells you when a colour is out of reach in paint, how close a mix can get, and why — the shortfall is measured, not asserted
• A new chart shows that the gap depends enormously on hue. Oranges and yellows mix almost exactly; blue reaches only 42% of what your screen shows. That is why a vivid turquoise or a clean violet needs its own pigment
• The tool is honest about its own limits: the mixing model's red and yellow sit exactly on your screen's, so warm colours score perfectly because of how the model is built — and the page says so rather than taking the credit

v2.0 · 9 August 2026

• The unit converter now has 351 units across 21 categories, up from about 180 — including rotation speed (rpm, rad/s, rev/s), which it had none of
• A new toggle reveals 102 genuinely odd units — firkins, furlongs per fortnight, the smoot — off by default, and every one converts correctly
• Every factor is now generated from a checked source rather than typed in by hand
• The altitude tool claimed to reach 100 km and actually stopped at 47. The Kármán line was being stored at the wrong height to make it fit, and its row showed a blank. The atmosphere model now runs to 84,852 m — the full standard — and the Kármán line shows its real height
• 21 more capital cities in the time zone tool, including Washington DC and Ottawa

v1.99 · 9 August 2026

• A SUVAT calculator — put in any three of displacement, starting speed, final speed, acceleration and time, and it works out the other two
• It shows the working, names which of the five equations it used and why that one, and draws the motion as three graphs
• When a question genuinely has two answers, it gives you both. A ball thrown upward passes a given height twice — once going up and once coming down — and most calculators quietly pick one
• Six worked examples you can load with one press, from a stone dropped 45 m to a car braking from 108 km/h

v1.98 · 9 August 2026

• The sort only reordered the list you pick from, not the cities already added — so the two sat on screen in different orders. Everything now follows the same one, including the day comparison strip and the copied text
• Sorting by time offset now reads straight down the page in order, because the anchor city takes its proper place in the sequence instead of being held at the top

v1.97 · 9 August 2026

• Twenty-two cities added, taking the list from 172 to 194 — mostly filling in North America and Europe, plus Jeddah, Manama and Nagoya
• Indianapolis and Monaco are worth singling out: both keep their own time zone rather than following a larger neighbour, which is exactly the kind of thing people open a converter to check
• Fixed a count that disagreed with itself — the list said one number and the cities beneath it were one short, until you changed something

v1.96 · 9 August 2026

• Neighbouring time zones used to look almost the same — the map only really used two colours, one for behind UTC and one for ahead, with everything else a slight change in shade
• Three zones were sharing a single colour outright. New Zealand, Tonga and Kiritimati were drawn identically
• The scale now runs the full way round from blue through green and orange to pink, so every zone is distinct, and the key shows exactly which is which
• Half-hour zones like India and Nepal get their own colour instead of being rounded into a neighbour

v1.95 · 9 August 2026

• The remove button was drawn on top of the clock on every city card except the first. Fixed — and on a phone the comparison grid was dragging the whole page sideways, which it no longer does
• Search and sort the city list — by name, by time offset, by region, or by what time it is there right now
• New presets: stock markets, one city for every time offset on earth, and everywhere that is inside working hours at this moment
• Sixteen stock exchanges showing open, closed, on a lunch break or on a weekend
• The map can colour every landmass by its time offset, with a key, on a toggle

v1.94 · 9 August 2026

• 172 cities instead of 50 — enough that every time offset in use anywhere in the world has a city on the map, including the odd ones like Kathmandu, Eucla and the Chatham Islands
• Every time zone there is — all 418 of them, grouped by region, searchable by city name as well as zone name, and colour-coded by whether people there are at work, awake or asleep
• A world map showing where the sun actually is, with the night side worked out from real solar geometry for whatever date and time you set — move the clock and the shadow moves with it
• It now tells you which two cities are the problem rather than just saying no time works — a grid of every pair, so you can see the one that is blocking everything
• Fixed some city names your browser still gets wrong, like Calcutta and Kiev

v1.93 · 9 August 2026

• 146 pages had search-result summaries that were the wrong length — 83 so long the end was cut off, 63 so short they wasted the space. All now sized to fit
• The site never identified its publisher in a way search engines could read. It does now, once, with everything else pointing at it
• The fifteen “chain reaction” walkthroughs were nearly unreachable — two links each. Every calculator they use now links back to them
• The Popular page was almost empty to a search engine. It now explains what the ranking does and does not tell you, which is worth reading anyway
• Several planned changes were dropped after checking that Google no longer uses them — there was no point shipping work that does nothing

v1.92 · 9 August 2026

• The bead-drop board was quietly broken. About one ball in five stopped in mid-air, the pile came out far too narrow, the “bias” control barely moved anything, and the board silently used one fewer row than it showed
• The predicted curve used to redraw itself to match the result — so there was nothing to check the result against. It now stays put, and the page reports how well the run actually fits it
• Bigger beads, walls that really hold them, and no more overflowing bins
• Your own data, four new ways: box plot, histogram, a normality check and a dot plot — plus median, quartiles, IQR, skew and outlier flagging
• Two new things to play with: six common distributions with what each one is for, and a demonstration of why averages turn into a bell curve even when the data never does

v1.91 · 9 August 2026

• The previous update was recorded incompletely — the site knew its own new version number, but this page and the internal notes still described the old one
• Publishing now stops if those ever disagree, so what you read here always matches what actually shipped

v1.90 · 9 August 2026

• One line in a settings file can quietly tell Google to ignore the site’s page list entirely. It happened once before and most of the site dropped out of search results
• Adding that line now stops the site being published at all, so it cannot happen again by accident

v1.89 · 9 August 2026

• Every page used to be marked as “updated today” every time the site was rebuilt. A typical update touches two or three pages, so this was telling search engines that all 270 had changed — which makes the whole signal untrustworthy and gets it ignored
• Now a page’s date only moves when its content really changes, so a genuinely updated page stands out and can be re-checked sooner

v1.88 · 9 August 2026

• The faint grid behind the page now moves about ten times more slowly. Where it used to catch up with your cursor in about a third of a second, it now takes around three seconds — so it drifts along behind rather than tracking you
• It also got cheaper. Moving that slowly, there is no point recalculating it sixty times a second, so it updates about seven times instead — and still stops completely once you stop moving

v1.87 · 9 August 2026

• Yesterday’s speed-up broke the search page pictures. Telling the browser each preview’s size — so the page stops jumping about while they load — accidentally locked their height, and every card ended up showing a huge close-up of its own middle. They are back to normal, and the page still does not jump

v1.86 · 9 August 2026

• The faint grid in the background was the main culprit. It followed the mouse exactly, and every single movement made the browser recalculate the whole page — several hundred milliseconds of work per second, spent on a decoration. It now drifts gently after the pointer instead of tracking it, updates about ten times a second rather than a hundred, and stops completely when you stop moving
• The moving demos on the front page kept running after you had scrolled past them, and while the tab was in the background. They pause now and pick up where they left off
• Typing in the search page was rebuilding every tool picture on every letter. It waits until you pause, and skips the rebuild entirely when the results have not changed

v1.85 · 9 August 2026

• Fixed: typing a sum gave you the answer and nowhere to go. Worse, the tools it listed underneath were matched on the digits — ask it 2+2 and it offered a two-stroke engine simulator and a student loan calculator. Now a sum points you at the calculator that can carry on with it, and the nonsense is gone
• Sixty more ways of asking. “How much does a fridge cost to run”, “what size beam for a 4m span”, “take home pay on 50k”, “joist span”, “parkrun time” — all of these used to miss, and now land on the right tool
• Filter the search by area or by kind — everyday things, safety-critical ones, rough ballpark estimates, or the ones that need your own numbers
• And every matching tool is shown as a card you can see, not just a list of names

v1.84 · 9 August 2026

• New: a full-page search. Type a question and it answers it — ask for “paint for a 4x5 room” and you get the wall area, the litres and the number of tins before opening anything. The tools nearest your question sit down each side as pictures, so you can recognise one you have never used
• Press Tab to finish typing. Start with “300k” and it offers the whole mortgage question — four keystrokes instead of thirty-five
• Fixed: the keyboard search was worse than the one on the front page. Asking the same question two ways gave two different answers — the quick search only did conversions and sums, and missed the calculators it could have opened already filled in. Both use the same engine now
• Whatever you have typed comes with you when you move to the bigger search, rather than making you type it again

v1.83 · 9 August 2026

• The pace calculator now gives you your splits — what the watch should say at every kilometre or mile, including the awkward last 0.195 of a marathon. Switch between even, negative and positive pacing and the finish time stays exactly the same; only the shape changes
• And what to actually train at. From one race result it works out your easy, marathon, threshold, interval and repetition paces — the same number read as a training plan instead of a ranking. Running only: the method has no cycling or swimming equivalent, so it stays hidden there
• Fixed: the tool lists on the front page were out of step with the area pages. New tools were being added to an area page without the front page catching up, so eight of the ten areas showed them in a different order. They now match, and the build keeps them that way

v1.82 · 9 August 2026

• New: give the paint mixer a colour and it works out the recipe. Ask for a slate blue and it comes back with “1 part Ultramarine, 2 parts Phthalo Blue, plus 10% white” — and a button to load that straight into the tray. It only ever suggests two or three tubes, because more than that muddies real paint
• And a proper colour wheel. Every pigment is plotted where it actually sits, your mix is marked on it, and a line runs through the centre to its opposite — which is the whole reason mixing a colour with its complement makes brown
• Plus a strip showing your mix tinted and shaded, from 60% darker to 80% lighter, with the hex code under each one
• Checked the colour maths against the things every painter knows — blue and yellow really do make green here, and complements really do cancel

v1.81 · 9 August 2026

• The payment you get when your fix runs out is now shown at the top, next to the one you pay today. On a typical UK mortgage that is a jump of about £550 a month — nearly a third more. The calculator always worked it out, but you had to scroll a long way down to find it
• And a chart of what happens at different revert rates, because nobody knows what they will be offered in five years. You can see the whole range rather than one guess
• None of this applies to a US-style loan fixed for the full term, so it stays hidden there
• Checked the sums. Payments, Canadian semi-annual interest, UK stamp duty and the repayment schedule all verified against published figures — no errors found

v1.80 · 9 August 2026

• The tool used to give tap drill sizes that do not exist. For M8 it said 6.75 mm and for M12 10.25 mm — no such drills. It now names a real one (6.8 and 10.2), which is what every workshop chart says, and tells you when the textbook rule falls between sizes
• Imperial threads now name an actual drill too — a ¼-20 tapped hole wants a #7, not “0.2000 inches”
• And it now works out how much thread you actually get. That percentage is what decides whether a thread strips, and it changes faster than you would think: on M8, going from a 6.6 to a 7.0 mm drill takes you from 86% thread down to 62%
• New: every nearby drill size, side by side, with what each one leaves you — too much thread and the tap fights you, too little and it pulls out under load

v1.79 · 9 August 2026

• A post or strut always buckles the easy way — across its thinnest dimension. The calculator was working it out for whichever side you had typed in the “depth” box, so a flat 100×20 bar could be reported as good for 424 kN when it would really give way at about 33 kN. It now always uses the weak direction
• It also tells you what bracing would buy. If you stop it bowing the easy way, the stronger figure applies — and that is now shown as a separate line rather than being the headline answer
• The end-fixing options now use the values engineers actually design to. A “fixed” joint is never perfectly rigid, and assuming it is overstates the safe load by about 69%. The textbook values are still there to compare against

v1.78 · 9 August 2026

• A beam can be plenty strong and still unusable. The tool checked the stress and said “ample”, then showed the sag as a bare number with nothing to compare it to. It now says outright whether you are inside the usual span/250 and span/360 limits — which is what actually decides whether a floor feels bouncy
• Correction: one steel beam in the preset list was slightly the wrong size. A “457×191” beam is actually 453.4 mm deep — the number in the name is a label, not a measurement. It made that beam look marginally stiffer than it is. Now corrected
• All the underlying beam formulas were checked against textbook results and against each other for the first time. They were right — and there is now an automatic check so they stay that way

v1.77 · 9 August 2026

• The whole point of both payoff methods is that when you clear a debt, the payment you were making on it goes onto the next one. The calculator described that in three places and was not actually doing it — so it was showing you a slower, more expensive plan than the one you would really be on
• On the tool’s own example that was 5 months and £107 of interest too many. With more debts the gap gets much wider. Now fixed, and checked against a separate model
• New chart: where each month’s money actually goes. Your payment stays the same size all the way through — what changes is how much of it is interest and how much comes off the debt. Early on a chunk is interest; by the end almost none of it is
• We also re-checked the claim that paying highest-interest-first always costs least. It holds — across 1,800 tested scenarios it never lost

v1.76 · 9 August 2026

• The energy calculator now counts standby. Anything left plugged in draws a little power for the ~8,700 hours a year it is not being used. A microwave clock at 2 W costs about 17 kWh a year — a sixth of what the microwave uses actually cooking
• And it finally has a chart. Your appliances ranked by cost, each bar split into “actually using it” and “sitting idle”, with a line showing how few things make up most of the bill — usually three or four out of a dozen
• Anything running around the clock has no standby to add, because it is never idle. A fridge or a router simply will not accept the figure
• Existing saved links still work exactly as before — the numbers are unchanged unless you add a standby figure yourself

v1.75 · 9 August 2026

• The salary tool now draws the rate you pay on your NEXT pound, across every salary. It is not the same as the rate you pay overall, and it does not simply climb — which is the bit that decides whether a raise or an extra shift is worth taking
• It shows the 60% trap. Between £100,000 and £125,140 the personal allowance is taken away at 50p per extra pound, and that 50p gets taxed too — so pay in that band is taxed harder than pay above it. Earn £110,000 and you keep 38p of your next pound; earn £130,000 and you keep 53p
• Correction: Scottish top-rate tax started too early. The 48% rate was being applied from about £116,760 of salary instead of £125,140, overcharging anyone above that by up to £377 a year. Fixed, and the tool now has an automatic check that catches this kind of threshold error

v1.74 · 8 August 2026

• You can now drag the poles around. There is a map of where the poles and zeros sit, and you can pick one up and move it — the frequency response, the Nyquist plot and the step response all follow as you drag
• Two new plots alongside it: a Nyquist plot, which shows the same information as a single loop measured against the point where a control loop goes unstable, and a step response showing what the system actually does over time, with the overshoot and settling time marked
• Correction: the stability margins could be badly wrong. Where a resonant peak makes the response cross the critical line more than once, the tool read the wrong crossing. On one example it reported a comfortable margin for a system that is actually unstable
• Correction: turning the gain below 0 dB flipped the phase by 180°. Reducing a gain is not the same as inverting it, and the phase plot — and both margins — were wrong for the whole lower half of that slider

v1.73 · 8 August 2026

• The two soft glows in the page corners are gone. On a wide screen they read as orbs sitting in the corner rather than as light, so the pages are a flat, even colour now
• The graph paper keeps clear of the page heading. It was creeping up behind the title and search box, and moving the mouse dragged lines around behind them. The gap is now measured from each page’s own heading, so it holds however you size the window
• Fixed a shadow that appeared around the page title when the mouse passed over it. Tool pages draw a card shadow around panels on hover, and the heading block was quietly counting as a panel. It had been doing that for a long time
• The paper is easier to see, and moves differently. Lighter lines, and it tilts very slightly with the pointer instead of sliding — sliding a grid of identical squares turns out to be almost impossible to notice

v1.72 · 8 August 2026

• The faint grid behind the homepage is now behind the whole site. It seemed like the right backdrop for a place that is mostly worked examples, so it is no longer just the front page’s decoration
• It drifts with your cursor rather than on a timer. Move the mouse and the grid eases the other way; stop, and it settles. That means it is still whenever you are actually reading a number off a chart — and it stays put entirely if you have asked for reduced motion, or used the Pause control
• Phones get it too. The old version switched itself off on small screens because it was expensive to draw. This one is drawn a different way, so it stays on — with a smaller grid, since the old squares were half a phone wide
• Fixed: selecting the word “Thumb” in the homepage title turned it into a solid orange block with the letters missing

v1.71 · 8 August 2026

• A cylinder is weaker coming back. The rod takes up part of the piston on the return stroke, so a typical cylinder gives about 75% of the force that way — and about 33% more speed for it. The calculator used to work out only the pushing direction and tell you to do the other one yourself
• It also warns about the pipe nobody sizes properly. Pulling back, the big end of the cylinder empties faster than the pump fills the small end — 53 litres a minute coming out of a 40 litre pump. Undersize that return pipe and the cylinder quietly loses force
• And the trick that makes a cylinder go fast: plumb both ends together and it moves at four times the speed, for a quarter of the force

v1.70 · 8 August 2026

• The retirement calculator already showed that a crash early in retirement is far worse than the same crash later. It now also shows the other half: while you are still paying in, a crash arriving early leaves you better off — every contribution during the slump buys in cheap
• Same returns, same average, opposite conclusion. The only thing that changes is whether money is going in or coming out

v1.69 · 7 August 2026

• The orbit calculator now works out transfers — how much speed you need to change, in two burns, and how long the trip takes. Low orbit to geostationary: about 3.9 km/s over five and a quarter hours
• And where the textbook answer stops being right. The two-burn route is described everywhere as the most efficient, but once the target orbit is roughly twelve times higher, a longer three-burn route genuinely uses less fuel — at one point saving fuel but taking ten years instead of five days
• Why geostationary is 35,786 km and not some other number — and why using a 24-hour day instead of the real 23 h 56 min puts it 77 km wrong

v1.68 · 7 August 2026

• The simulator now has a delay. Real processes do not respond the instant you act — and that gap, not slowness, is what makes control hard. Turn it up and watch a perfectly good setting fall apart
• Three real tuning methods replace four made-up presets. Press a button and it works out the settings from the process itself, the way engineers actually do it
• They disagree by a factor of five on the same loop — and that is the interesting part. They are not arguing about the arithmetic, they are arguing about how much safety margin is worth having

v1.67 · 7 August 2026

• Springs have a resonance of their own, and squeezing one faster than about a thirteenth of it makes the coils stop moving together — they pass a wave along the spring instead, bang into each other, and break. It is why valve springs fail at one particular engine speed rather than gradually
• The calculator’s own example spring turned out to fail this — fine up to about 3,100 rpm, in trouble above it. It now says so, and tells you the speed limit
• It also checks the two things a spring hits before it runs out of strength: the coils touching each other (after which it is a solid bar, not a spring) and buckling sideways like an over-long column

v1.66 · 7 August 2026

• Cable ratings in the book assume ideal conditions — a cool 30 °C and no more than three wires run together. Bundle six in a hot loft and you have about 65% of the printed capacity left
• That is enough to change the answer. For a 20 amp circuit in those conditions, the size the table suggests is genuinely too small — the tool now says so, and tells you what to use instead
• It also separates two things people conflate: what the cable itself can stand, and what the terminals it screws into can stand. The second caps the answer, but the first is what you scale down from — which is exactly why better cable is worth buying for a hot run

v1.65 · 7 August 2026

• It now does planetary gears — the sun-and-ring arrangement inside almost every gearbox, hub gear and electric drill. Hold a different part still and the same three gears give you a different ratio, which is how an automatic gearbox changes gear without moving anything
• It tells you if the set can actually be built. Two things have to work out as whole numbers or the parts simply will not go together — and the ratio looks perfectly fine either way, so nothing warns you until you have the metal in your hands
• Real sizes, not just ratios. Set the gear module and you get tooth diameters, shaft centre distances, and how much room the whole train needs
• Gears below about 17 teeth get flagged. Cut smaller than that with a standard cutter and it carves into the root of each tooth, weakening it. The tool’s own default example turned out to have one

v1.64 · 7 August 2026

• This site still runs no analytics, sets no cookies, and sends nothing to anyone else — and now an automated check enforces that on every build. If anyone ever added a tracking script, a cookie, or a connection to an outside service, the site would refuse to build
• Verified as it stands: 258 links to files the pages load, every single one from this site. Zero cookies. Exactly one outside service — the exchange-rate feed used by the currency converter, which has always been named on the privacy page
• We decided not to add visitor analytics. Which pages get visited is already visible from the web host's own logs, without sending anything from your browser. So nothing changes for you, and the promise on the privacy page stays exactly as it was

v1.63 · 7 August 2026

• The tools list, the map and the popular list all start drawing sooner — the last three pages still waiting on a large script before showing anything. Every page on the site now loads it alongside rather than before
• The new two-way test caught a real one first: done naively, the A–Z page would have displayed “0 of 0 tools”. It was fixed properly instead, then re-checked
• The site was publishing its own build scripts. 635 kB of tooling sat in the published folder and was downloadable. Moved out — no passwords or keys were ever in them

v1.62 · 7 August 2026

• The Rulebook page now starts sooner too, the same change the homepage got last time — verified to render identically first
• A new automated test renders each page two ways and compares them. It immediately found that the A–Z tools page would have shown “0 of 0 tools” if given the same treatment — with no error message. That change was not made
• The test also checks that it is genuinely working, rather than quietly comparing two broken copies and calling them a match

v1.61 · 7 August 2026

• The homepage was waiting on 57 kB of JavaScript before it could show you anything. It now draws first and loads that script alongside, so the page appears sooner on a slow connection. Nothing about it looks or behaves differently — checked line by line against the old version
• A small bug found on the way: the “rule of the day” box could show a web address where the calculator’s name should be. It now always shows the name

v1.60 · 7 August 2026

• Every calculator page was downloading the entire Rulebook — all 135 rules — to show the one or two that apply to it. That is 134 kB of data for a box containing a sentence. The box is now built when the site is published, so the page just has it. About 47 kB less to download on your first visit to any calculator
• The offline cache was fetching it a second time, on every page, along with the homepage animations — on pages that use neither. Both now download only when something actually needs them
• Search engines and readers without JavaScript can now see the rule box at all. Previously it was drawn after the page loaded, so it was invisible to both

v1.59 · 7 August 2026

• The test suite could not run at all. It needs Node, and Node was not installed on the build machine — so the checks that read every page for broken scripts, invalid HTML and a working search box had been silently skipped. Reinstalled; all 259 pages pass
• The build itself was crashing before it validated anything. A missing image library took the whole thing down at the point where it draws share pictures — which is before it checks sitemaps, counts, links and schema. A share-image dependency could stop every integrity check on the site from running
• Chemical and maths notation was drawing as blank boxes on share images. CO₂, VO₂ max, log₂ and V₁/V₂ all appeared as empty rectangles when a page was shared. All 247 share images redrawn
• v1.57 was missing from this page. The entry lost its heading at some point, so the release that corrected the bolt-torque figures — the most safety-relevant fix on the site — was not listed here. Restored above
• Internal documentation corrected: six counts had drifted, the rulebook of project rules disagreed with itself about which rule was which, and the copy-paste command for archiving a release pointed at a folder that does not exist

v1.58 · 3 August 2026

• It now has a size. Set the bore, stroke and cylinder count and the animation stops being just a picture — you get piston speed, the forces on the parts, displacement and power
• What actually limits an engine is piston speed, not rpm. A ship engine at 102 rpm, a car at 6,000 and a Formula 1 engine at 15,000 have rev counters that differ by 147 times — and piston speeds that differ by three
• The piston is fastest well before half way down, around 75° after top dead centre rather than 90°, because the connecting rod swings as well as the crank
• A redline is a strength limit, not a breathing one. The load on the piston rises with the square of engine speed — from 356 to 2,226 times gravity between 2,400 and 6,000 rpm
• Ignition timing is a stopwatch, not a protractor. Burning takes about the same time whatever the revs, so the spark has to fire 12° early at 1,000 rpm and 72° early at 6,000 to land in the same place

v1.57 · 3 August 2026

• The bolt torque calculator was recommending too much torque on every size up to M16. The standard gives class 8.8 bolts two different strengths depending on diameter, and the page only knew about the higher one — so it asked for 3.4% more than it should. Corrected, along with the imperial grade 2 figure, which was 40% the other way
• Two tools were giving different answers for the same bolt. The screw sizing tool and the torque calculator disagreed about how strong an M10 class 8.8 bolt is. They agree now, and a check keeps them agreeing
• One chart was a hundred times out. The bolt-size-versus-torque graph topped out at 15 N·m where a big bolt really needs about 1,500, and the caption under the main figure said “0.75%” where it meant 75%
• The other seven safety-critical tools were checked against their standards — cable ampacities, beam formulas, buckling, thread sizes, breaker trip bands — and were correct

v1.56 · 3 August 2026

• The circlip material and safety-factor dropdowns could not be read once you opened them — pale text on the browser’s own white pop-up list. They now carry their own background, like every other dropdown on the site

v1.55 · 3 August 2026

• The published circlip load table turned out to be a formula. A groove wall is a flat ring of metal, and the rating is just its area times how hard the material is — which means you can work it out for your shaft instead of the soft one the standard assumed
• The standard assumes 200 N/mm², softer than nearly any real shaft. Ordinary C45 shaft steel carries about 1.55× the book figure. Whether that helps depends on the size: a shaft nearly always fails at the groove, a bore often fails at the ring instead
• A 0.2 mm radius on the cutting tool costs 39% of a 20 mm shaft’s rating — and the groove still measures full depth, so nothing catches it
• Even a perfect groove rattles. The standard groove is 0.10 mm wider than the ring, so a retained part can always move that far. Under a load that reverses, that gap is where the hammering comes from
• One figure in the published source contradicts its own neighbours. It is passed on as published, with a note saying so, rather than guessed at

v1.54 · 3 August 2026

• Sampling too slowly does not lose your signal, it moves it. At an 8 kHz sample rate, 7 kHz, 9 kHz and 15 kHz all come out as 1 kHz — and nothing in the recording can tell you which it was
• Bode plots: the straight lines are 3 dB out exactly where you read them, and the phase construction is worst a decade away rather than at the corner. The two errors never happen in the same place
• “Settled after five time constants” still leaves 0.67% to go — fine for a heater, 27 counts on a 12-bit converter. Getting to 99.9% takes seven

v1.53 · 3 August 2026

• Week numbers now explain the messy bit — 2026 has 53 weeks, so anything planned around “52 weeks” is short this year. And 1 January 2027 belongs to week 53 of 2026, which quietly breaks spreadsheets
• Clock hands overlap eleven times in twelve hours, not twelve — there is no overlap between 11 and 12. All eleven times are listed to the millisecond
• Water’s thickness changes six-fold between freezing and boiling, while its density barely moves 4%. So hot water flows more than three times more turbulently down the same pipe at the same speed
• The circlip calculator is thinner still, but filling it out needs engineering data I could not check properly — so it is still waiting rather than guessed at

v1.52 · 3 August 2026

• You can see your whole array now. The diagram was a fixed width, so on a narrow screen you had to scroll sideways to see half your own drives
• The drives look like drives — a bay, a platter and an activity light — instead of flat coloured blocks
• It shows which drives you can afford to lose, which is the entire reason for picking a RAID level and was nowhere on the picture before
• On RAID 5 and 6 it says any drive may fail and the marked one is just an example — because marking one and saying nothing would suggest it was special

v1.51 · 3 August 2026

• Every tool can now tell you how much to trust its answer. Your measurements are rough, so the answer is too — press one button and it works out the range
• And which of your numbers is causing it. On a beam, the span is 94% of the uncertainty — so that is the one worth measuring properly, and fussing over the others is wasted effort
• When nothing dominates, it says so rather than picking one and sounding confident
• Pages print properly at last — ink on white instead of a full-page dark background, the controls stripped out, your answer and the warnings kept, and the web address on the bottom

v1.50 · 3 August 2026

• Yesterday’s new box overstated one of its own answers. It said a rule was “never” accurate when it is accurate at light loads, just not where people use it. Fixed — and the true version makes the point better
• “A 100W device costs about £10 a month” has quietly expired — it assumes an electricity price from years ago and now understates the bill by nearly half
• “220 minus your age” is spot on at 40 and drifts either side, flattering the young and short-changing the old
• Splitting a network promises four addresses on the smallest useful split; you actually get two
• Plus altitude, mortgage rates, tipping, race times, and concrete in the cold — eighteen rules now show their working

v1.49 · 3 August 2026

• Rule pages now put a number on the shortcut. Every rule already said when it fails; ten of them now say by how much — what the rule gives, what the exact answer is, and where it stops being safe to use
• The Rule of 72 is under 0.1% out at 8% and holds to within 5% up to about 19% interest
• “Double the load, an eighth of the life” is 26% optimistic for roller bearings — it is never within 10% anywhere. The page says so rather than quietly recommending it
• A litre of water is a kilogram to within 2% up to 65°C, and 4% out in a kettle
• All of it worked out when the page is built, so the words can never drift away from the numbers

v1.48 · 3 August 2026

• Every chart on the site now draws at the same scale. There were 147 charts built at 86 different sizes, so labels came out either microscopic or chunky depending on the page. They are all correct now — and one had been rendering 48% too big
• Charts stay readable on a phone instead of shrinking their labels to nothing
• The site moves now. Content settles in as it loads, numbers register when they change, buttons press, and chart lines draw themselves. All of it switches off if your device asks for reduced motion
• Every tool ends the same way. Seven were missing their limits box — each now says what it actually cannot tell you, rather than carrying a generic disclaimer
• Resistors: can you buy this value, what two resistors make it, what the SMD code means, and what power rating you need

v1.47 · 3 August 2026

• “Can I actually buy this value?” — type any value and get the nearest stocked part, how far out it is, and whether your number falls inside its tolerance anyway. 5k doesn’t exist, but a 5.1k part can legitimately be 5k
• Two resistors when one won’t do — it finds 300Ω + 4.7kΩ in series for exactly 5k, which is not the pairing most people would think of
• SMD codes — 473, 4702, 4R7 and the EIA-96 letter codes. All missing before, and searched at least as often as the colour bands
• Will it survive? The power it dissipates and the rating you actually need, which is roughly double what the arithmetic allows
• The page finally answers its own question about why there’s a 4.7k and no 5k — and the textbook answer turns out to have holes in it

v1.46 · 3 August 2026

• The rolling race — a marble, a disc, a football and a hoop released together. The order never changes, and mass and radius have nothing to do with it. A hoop gets exactly half the acceleration a frictionless block would
• Give it too little grip and it slips instead — and arrives sooner, because it stops wasting energy on spin
• Pushing something up. A ramp saves force and never saves energy. At the 1:12 gradient used for wheelchair ramps, under a third of your effort becomes height
• Every angle now shown three ways at once — degrees, percent and 1:N. A 10° hill is signposted 17.6%, which catches people out constantly
• Angle of repose for sand, soil and gravel — and picking one sets the friction, because the two are the same measurement

v1.45 · 3 August 2026

• It now tells you what is actually holding you back — the line, the TCP window, the disk, or congestion. The old version had one vague “efficiency” slider covering all four, which hid the only question worth asking
• Latency limits bandwidth. A 15 GB film on a 500 Mbps line takes 38 minutes with a default window and 4½ minutes with a bigger one — same connection, no upgrade
• A 7200 rpm hard disk is not the bottleneck on a gigabit link, which surprises most people. An SD card is
• A 1 TB drive in the post moves data at 93 Mbps and beats any slower connection. The page works out when the van wins
• Two charts: every speed limit side by side, and the point where a faster line stops helping

v1.44 · 3 August 2026

• It was under-counting. The old version mixed two different conventions, so the materials it listed came up about 5% short of filling the volume it quoted. Fixed, and the cement content now matches published figures for a 1:2:4 mix
• Water is now a dial with a curve behind it — two extra litres in a 25 kg bag looks like nothing and costs about a quarter of your slab’s strength
• A curing chart with a temperature slider — drive on it after 4.8 days at 20°C, or 9.5 days at 5°C. The famous “70% at seven days” turns out to be a British answer
• Slabs, trench footings, post holes and steps, each with its own measurements, plus a bucket-by-bucket recipe for one mixer load and a warning when the job has outgrown the mixer
• Two new rules: what water does to strength, and why cold delays concrete rather than ruining it

v1.43 · 3 August 2026

• The UK now reaches back to 1900 — a first-class Titanic ticket was £30 in 1912, which is about £2,989 today. The best suite on board was £870, or roughly £87,000
• Examples that run backwards — £1,000 today was about a tenner in 1912, and a current iPhone costs what $128 bought in 1970
• Years before 1950 come from a different, coarser index, because CPI does not go back that far. Every one of them says so on screen rather than pretending otherwise

v1.42 · 3 August 2026

• Six real prices you can try in one click — a Concorde return, a 1970 house, a ZX Spectrum, the first iPhone, a 1965 Mustang, the original Walkman. That £1,070 Concorde ticket is £8,236 today
• The graph now toggles between what one pound did over time and what your actual amount would be worth

v1.41 · 3 August 2026

• The inflation calculator now runs to 2025, plus the latest month of 2026 — UK to May, US to June, taken from the ONS and BLS. A part year is labelled as one rather than dressed up as an annual figure
• Fixed the “not financial advice” box overlapping the panel above it on every Finance page

v1.40 · 2 August 2026

• Inflation Calculator — what a price in any past year is worth in today’s money, and the other way round. UK and US. £100 in 1970 is £1,557 today
• It can also run forward, at a rate you choose — but a projection is drawn dashed and labelled, because nobody knows next year’s inflation
• And it handles the years prices fell: $100 in 1920 needed only $70 in 1940

v1.39 · 2 August 2026

• Every tool page now says what kind of thing it is — half of them never used the word “calculator”, “converter” or “simulator” anywhere a search engine looks. 41 pages did; all 85 do now
• Ten tools gained the word in their name, including Beam Bench, which is now Beam Deflection & Stress Calculator. The rest kept their names and gained the term in the line underneath

v1.38 · 2 August 2026

• All six live previews sit on one row instead of five plus a stray sixth. On a phone they fall to two rows of three, where six would be too small to see

v1.37 · 2 August 2026

• Rule of the day and the live demos are back near the top too, alongside chains and the map. Favourites stays at the foot of the page

v1.36 · 2 August 2026

• Chain Reactions and the Thumbprint map are back near the top, under the ask bar and the counts

v1.35 · 2 August 2026

• The About page now describes how the work is actually done — every calculation built and tested independently before the page exists, twenty-nine checks that fail the build, and prose about a tool tied to that tool’s own code so it cannot quietly go stale
• A corrections policy — anyone can report an error without an account or a name, and every fix is logged publicly, including when the mistake was ours
• Each tool now records when it last actually changed, taken from the archived releases rather than a date chosen to look recent

v1.34 · 2 August 2026

• The homepage gets to the tools faster — the ask bar, the counts, then the calculators. Rule of the day, chains, demos and favourites are all still there, one scroll down
• Every citation on the sources page is now tied to the tool it describes, so if a calculator changes the citation gets re-read rather than assumed
• Fixed a stray row that made the changelog claim the wrong current version

v1.33 · 2 August 2026

• Back to “the numbers you keep looking up” — the line the site carried for 75 releases, and the one that actually says what it is for

v1.32 · 2 August 2026

• Four area pages were calling tools by out-of-date names — DIY still said “Tea Brewing” after it gained coffee, and “Screw & Stud” after it gained tap drills. Fixed, and the area pages are now checked against the real tool list on every build

v1.31 · 2 August 2026

• Version history on a tool now lists only changes to that tool — 244 entries down to 42. Site-wide housekeeping lives in this changelog, where it belongs
• The finance disclaimer moved below the results. Same words, but you see a number before you see a warning about it
• Popular waits until it has something to say — a ranking built on one or two clicks is not a ranking
• Homepage title now says what the site is, rather than only what it is called

v1.30 · 2 August 2026

• Tool names on the homepage were too long and wrapped onto two lines — they had picked up the little descriptive tagline that belongs on the tool’s own page. Names only now, and nothing wraps, even on a phone
• Search-result titles keep their tagline, where it is the only context you get

v1.29 · 2 August 2026

• 16 tools were missing from the homepage — the area cards had not kept up as new calculators shipped, and seven of them showed the wrong tool count. Health listed 3 of its 6. All 85 are now on the front page, with the counts generated from the real list so they cannot drift again

v1.28 · 2 August 2026

• Found a wrong number? Every tool and rule page now has a line at the bottom that takes you straight to the corrections form with the page already filled in. Anonymous, no account
• Recently added — the newest calculators are listed at the top of this page, so a return visit shows what changed without reading the whole history

v1.27 · 2 August 2026

• A theme control with words on it — System, Light or Dark, spelled out in the share panel. The icon in the bar still cycles, and now tells you what it changed to
• Every chart has a name now — the last ten animations and graphs were invisible to a screen reader. A build check stops that happening again
• The Rulebook without JavaScript — all 122 rules were always listed there; the caption made it sound like they were not

v1.26 · 2 August 2026

• A short tour on your first visit — four steps explaining the one thing that is easy to miss: every rule of thumb has an exact calculator behind it. Dismissible, and reopenable from the footer
• Keyboard navigation — j and k move between rules and tools, Enter opens, Esc clears. Arrow keys join in once you start, so scrolling still works normally

v1.25 · 2 August 2026

• Build your own workflow — string tools together in the order you actually use them, each step remembering the numbers you had. No account
• Share the whole sequence as one link — send a colleague the route you took, not just the answer. Their browser asks before saving it
• A next-step prompt on the page — part-way through a workflow, each tool tells you what you lined up next

v1.24 · 2 August 2026

• Copy any result as text, Markdown or CSV — one button on every tool. Tools with a data table export the whole table: 30 rows of amortisation schedule, or a full bearing life-vs-load curve
• Recent calculations — the last 15, with the answer you got, one click to reopen with every input restored. Stored on your device only, with a Clear button
• Copy link — the same shareable link as before, now easier to find

v1.23 · 2 August 2026

• Search that copes with how people actually type — “home loan”, “waist size” and “air conditioning” all found nothing before, because every word had to match the same entry. Now the rarest word wins when no single entry has them all
• Tags — filter the Rulebook and the A–Z list by everyday, safety, ballpark and your numbers, on top of the existing areas. Combine them, and share the filtered link
• A dozen rules were showing raw formatting codes in the Rulebook, on the homepage and in Google results. Fixed, with a check so it cannot come back
• The homepage now says what “Popular” is counting

v1.22 · 2 August 2026

• Waist-to-Height Ratio — keep your waist under half your height. One tape measure and one boundary, and it catches the cases BMI gets wrong in both directions
• Motor Starting & Inrush — why the breaker trips on start but never in use, and what star-delta, soft starters and drives really cost you in torque
• Integral Windup & Anti-Windup — why a correctly tuned loop still overshoots when the valve is already fully open, and the two fixes that do not involve retuning
• Six new rules of thumb

v1.21 · 29 July 2026

• Password Strength & Crack Time — why a five-word phrase beats eight random characters by four thousand times, and why “P@ssw0rd!” is worse than it looks. Nothing you type leaves your browser
• A/B Test & Sample Size — how many visitors a test really needs (usually far more than expected), and what your existing sample could actually have detected
• On-Off Control & Hysteresis — why a bigger boiler switches on and off more often, and why the worst day for your heating is a mild one
• Five new rules of thumb

v1.20 · 29 July 2026

• Battery Sizing & Runtime — how long a battery bank really lasts, once you take off the half you cannot use, the capacity that vanishes at high draw, and the inverter’s cut
• Sweat Rate & Hydration — weigh yourself before and after one session and you know how much you actually need to drink. It varies fivefold between people, so no guideline fits you
• First-Order Lag & Dead Time — for the control engineers: get a plant model out of a single step test, and find out whether PID can control it
• Four new rules of thumb to go with them

v1.19 · 29 July 2026

• All 107 rules now have a “When it fails” section — a real example of a case where following the rule gets you the wrong answer, not a vague warning
• It sits right after the explanation and before the calculator, because knowing when a shortcut does not apply is most of what makes it safe to use

v1.18 · 29 July 2026

• Every calculator now lists the releases that changed it — tucked behind a “Version history” button near the bottom, so it is there when you want it and out of the way when you do not
• Worked out from the archived copy of every release rather than from notes written afterwards, so it reflects what actually shipped

v1.17 · 29 July 2026

• The search bar was covering the breadcrumb on phones — on every tool page the “Rules of Thumb › Mechanical › …” trail sat underneath it and could not be read or tapped. Fixed
• New tagline: “close enough, precisely” — what the site is for, rather than what it contains
• The opening line now covers more of what people actually come here for, and ends where the site goes deeper than most

v1.16 · 29 July 2026

• The Unfold button on the geometry page did nothing unless you had already moved the slider — now fixed, so a solid folds flat and back from the moment you pick it
• A new live demo on the front page: a cube, dodecahedron, rectangular prism or triangular prism — a different one each visit — turning and unfolding into its flat net, then folding back up

v1.15 · 29 July 2026

• Pick the kind of mortgage, not just the country — buy-to-let, first-time buyer, interest-only, FHA and VA, investor loans. Each one suggests the deposit and rate that product usually needs, and you can change any of it
• Buy-to-let is limited by the rent, not by your income, and the tool now shows you the largest loan your rent will actually support — usually less than a 25% deposit implies
• Yield is not profit. You get gross yield, net yield after running costs, and what you actually earn on the cash you put in — which at today’s rates can be less than nothing
• Includes the extra 5% stamp duty on a second property, and warns that interest-only leaves the whole loan owed at the end

v1.14 · 29 July 2026

• Every finance page now says plainly that it is not financial advice, right at the top where you see it before typing — four of them previously said nothing at all
• Expanded the Terms of Use on what the finance tools are and are not, including that this site is not regulated by the FCA and that buy-to-let lending usually is not either
• Every one of these figures is an estimate. For real money decisions, talk to a qualified adviser

v1.13 · 29 July 2026

• “220 minus your age” is an average, not your number — four published formulas shown together so you can see they disagree by 10 to 25 beats, which moves every zone
• “Zone 2” means two different heart rates — your watch and your coach are probably using different definitions, about 24 beats apart. The tool shows both
• Enter a real measured maximum and it uses that instead, because it beats every formula
• Tells you when a zone falls below your resting heart rate, which means you cannot train in it at all

v1.12 · 29 July 2026

• Every tool’s questions and answers are now published in a form search engines understand — six pages had none at all, so 25 answers were invisible to search
• Nine pages had an answer that no longer matched what the page said, including the car finance page describing a fee it now handles. All corrected
• The published version is now built from the answers on the page, so the two can never disagree again

v1.11 · 29 July 2026

• Work out what each room needs, not just the house — every room gets its own target temperature and ventilation rate, and you get the radiator size it actually needs
• It tells you which rooms cannot be done with one radiator at a heat pump’s flow temperature — the thing that quietly derails a retrofit
• Bathrooms are a ventilation problem, not a heating one — the new breakdown shows why a small one needs more heat per square metre than any bedroom
• Four house presets to start from, rooms you can add and remove, and the whole layout kept in the share link

v1.10 · 29 July 2026

• A rule about student loans was giving the opposite advice to its own calculator — it said overpaying buys you nothing, which is true in the UK but wrong in Australia and New Zealand, where there is no write-off. The rule now says where it applies
• Every rule that describes what a tool does is now tied to that tool — change the tool, and the rule gets flagged for re-reading before the change can ship

v1.09 · 29 July 2026

• What an electric car actually costs per mile, at home, off-peak, workplace and public rapid rates — next to a petrol car for comparison
• How long a charge really takes, including why the last 20% is the slow 20% — and why a 350 kW charger is often no quicker than a 150 kW one
• A year of driving costed out from your mileage and how much you charge away from home — it will tell you when an EV works out dearer
• Charges you for the energy that never reaches the battery, because your meter does
• UK, US and EU tariffs, fuel prices and units

v1.08 · 29 July 2026

• Three pages were describing limits they no longer have and have been corrected — the bearing calculator said it could not combine radial and axial load (it can), the projectile page said it ignored air resistance (its golf mode models drag and spin), and the currency converter said no spread was applied (it has a spread control)
• A new check now catches this class of mistake — when a tool's workings change, anything it says about its own limits gets flagged for re-reading before the change can ship

v1.07 · 29 July 2026

• Which ISO week any date falls in, and which dates any week covers — with a month calendar showing the week number on every row
• The years with 53 weeks, which is when weekly payroll gets an extra run
• The US Sunday-start week number shown alongside, because the two conventions disagree for several weeks most years
• Warns you when a date belongs to a different week-year than calendar year — 1 January 2027 is week 53 of 2026

v1.06 · 29 July 2026

• Fixed the underlying cause of the last two updates. A cleanup script was removing styling whenever a name matched, without checking the two things actually meant the same. It now compares what the rules say — and tells you what it decided to leave alone

v1.05 · 29 July 2026

• Removed duplicated styling left behind by yesterday’s repair — identical rules defined twice on two pages. Nothing looked different; there was just more of it than there needed to be

v1.04 · 29 July 2026

• Removed styling from 26 pages that the shared stylesheet already provided — same appearance, less to download
• Two result panels were caught in the crossfire and have been repaired — they shared a class name with a completely different component

v1.03 · 29 July 2026

• Four tools were describing themselves wrongly — still claiming not to do things they had been doing for versions. All corrected
• Returning visitors were getting a stale homepage. The cached copy of the demos outlived the update that changed them

v1.02 · 28 July 2026

• New: Heat Loss & Heat Pump Sizing. How many kilowatts your home actually needs, from how it is built — and where the heat is going
• The radiators decide it, not the cold. A radiator gives about a third of its rated output at a heat pump’s temperature, so the same room needs roughly three times the radiator. That is the thing nobody mentions
• Insulating beats upsizing. Improving the fabric shrinks the plant, the radiators and the running cost at once

v1.01 · 28 July 2026

• The student loan calculator now covers Australia, New Zealand and the US as well as the UK — and they work very differently
• Australia charges a rising rate on your whole income, so a small raise can cost more than it pays. New Zealand is interest-free, so the debt shrinks in real terms. Neither is ever written off — so unlike the UK, paying extra there is worth it

v1.00 · 28 July 2026

• New: UK Student Loan Calculator. Plans 1, 2, 4, 5 and postgraduate, projected across your whole career rather than just this month
• It answers the question that actually matters: will you ever clear it? On typical numbers you repay a fraction and the rest is cancelled — which is why paying extra is usually money thrown away
• Plan 5 is a different deal. Forty years to write-off instead of thirty, and the tool shows what that costs you

v0.99 · 28 July 2026

• Car finance now works out an early settlement figure — what it costs to end the agreement, and how much interest you get back for the months you no longer owe
• Debt payoff handles a one-off lump sum — a bonus or a refund — and shows what waiting a year to use it would cost you

v0.98 · 28 July 2026

• Statistics can now compare two sets of numbers and tell you whether the difference between them is real or just noise — with how big it plausibly is, not only a yes or no

v0.97 · 28 July 2026

• The currency converter now shows what you really receive, not just the mid-market rate nobody is offered — put in the spread and any fixed fee and it works out the true cost
• Small amounts are hit hardest: a $5 fee on $100 at a 3% spread costs you 7.8%, not 3%

v0.96 · 28 July 2026

• The resistor decoder reads 5- and 6-band parts now — which is most of what is in a modern parts drawer, and previously it said outright that it could not
• Concrete tells you what to order, not what you end up with. A wastage allowance for spillage and what stays in the mixer — running out mid-pour leaves a permanent weak line

v0.95 · 28 July 2026

• Balls were slowing down as they fell into the buckets — something that was quietly damping them on the way down. Removed, so they drop and pack properly instead of hanging in towers
• The spread is right at last. It had been too wide, then too narrow; the ball now simply falls into the slot the pegs already chose for it
• Nothing stops in mid-air — a ball only comes to rest with the floor or another ball underneath it

v0.94 · 28 July 2026

• Balls were sticking in mid-air among the pegs and piling into a clump. They can now only come to rest once they have actually landed in a slot
• The curve was too wide. Balls kept drifting sideways after the last row of pegs, past the point where any decision was left to make
• It now matches the maths: spread of 1.70 against a predicted 1.73

v0.93 · 28 July 2026

• The dividers are real. They were drawn on but had no substance — balls passed straight through and the pile spread into any old shape
• One slot per possible outcome. There were 44 slots for a board with 13 possible results, so the pattern never lined up
• It now builds a proper bell curve — measured against the exact distribution it is supposed to produce, and it matches

v0.92 · 28 July 2026

• The Psychrometer can be shared. Set up an air state, capture points to compare, pick a city — the link now carries all of it
• Statistics answers the real question: how much you can trust an average taken from a sample, with the confidence interval and how much more data it would take to halve it
• Data Transfer Time explains the slow gigabit link. Distance, not bandwidth, is usually what is limiting you — and the tool now says so, and what to do about it

v0.91 · 28 July 2026

• Thumbprint no longer runs off the top and bottom. It was refusing to zoom out far enough to fit — and then sizing itself before the bubbles had finished spreading out
• Checked at phone, narrow and desktop widths, and the reset button brings the whole map back into view from anywhere

v0.90 · 28 July 2026

• The springs are drawn as coils now, not zigzags — they curve, they bulge when squashed and pull thin when stretched, and they keep the same number of turns throughout, because real ones do
• The pendulums sit properly in their panel instead of hanging off the top edge

v0.89 · 28 July 2026

• The test suite now guards releases rather than waiting to be remembered — one command runs everything and refuses to pass if anything is broken
• Every calculator now describes itself properly to search engines — what it is, that it is free, that it needs no account. No invented star ratings

v0.88 · 28 July 2026

• The full test suite runs for the first time. It had been sitting in the project for most of its life, unable to start — and was itself broken in three ways once it could
• All 211 pages pass, including a test that loads the shared code the way a browser does and drives the search palette for real

v0.87 · 28 July 2026

• Every page on the site was loaded and checked — all 211 of them, on a wide screen and a phone-sized one. Everything works
• Shorter descriptions in search results. 36 pages had descriptions too long to fit, so the end was being cut off. They now say what they need to in the space available

v0.86 · 28 July 2026

• Share cards for everything. Link a calculator anywhere — a message, a forum, a chat — and the preview now shows that calculator by name, not the same generic image 108 pages were sharing
• The chains too, which are the ones most worth passing on
• 199 cards in total, generated from each page’s own title and description, so they can never drift out of step with the page

v0.85 · 28 July 2026

• Microfarads, not just kVAR. The tool sized correction in kVAR — but nobody orders a capacitor in kVAR. Give it a voltage and it now tells you the part
• Three-phase, delta or star. A star bank needs three times the capacitance of a delta one for the same correction — which is exactly the sort of thing that gets the wrong part delivered
• What correction is really worth: current before and after, kVA of supply capacity freed up, and how much the cable losses drop

v0.84 · 28 July 2026

• Drop from 300 m, not 10 m. The Pisa preset used to drop things 1.6 m — the actual tower is 56 m. Now it is, and the result is completely different: the ping-pong ball lands four seconds late
• The equations are on the page. How long a fall takes in a vacuum, how fast it lands, and exactly what the air cost you as a percentage
• Build your own object. Any mass, size and drag coefficient — and terminal velocity for each, with how much of it they actually reached

v0.83 · 28 July 2026

• Combined radial + axial load. The bearing calculator used to say this was impossible without a manufacturer catalogue. For the bearings it covers, it isn’t — so it now does it, and shows the factors
• A bit of thrust is often free. Below a threshold the bearing carries it for nothing; above it, life falls fast. The tool tells you which side you’re on
• Size backwards from a target life. Say how many hours you need and it works out the rating you have to buy, then names the smallest bearing in each series that clears it

v0.82 · 28 July 2026

• Electrical Circuit now covers Kirchhoff. A two-loop, two-source circuit solved in front of you, with every line of the working shown — the classic problem everyone meets and nobody enjoys
• A junction calculator. Add branches, mark each in or out, leave one blank and it solves it. Fill them all in and it tells you whether they balance
• Negative currents are explained, not hidden. Guess a direction wrong and the arrow flips and says so — that is the sign convention doing its job, not an error

v0.81 · 27 July 2026

• New: Clock Angle Calculator. The angle between the hour and minute hands at any time, with the working shown — people were already searching for this and finding nothing here
• It answers the trick question properly: at 3:30 the hands are 75° apart, not 90°, because the hour hand has already crept halfway towards the 4
• And the follow-ups: every time the hands overlap, sit opposite, or form a right angle — 22 overlaps a day, not 24, and 44 right angles

v0.80 · 27 July 2026

• The map was splitting words in half — “Mathematic s”, “Calculato r”, “Temperat ure”. Words now stay whole, and each bubble is sized to fit its longest one

v0.79 · 27 July 2026

• The Thumbprint map is much taller — it was cropping bubbles off the edges before you had touched anything
• It now sizes itself to fit the whole map when it opens, and again if you resize or rotate your device, instead of only doing that when you press reset

v0.78 · 27 July 2026

• The search box now handles the percentage questions people get wrong. Type remove 20% vat from 120 and it answers £100 net, £20 tax — and points out that subtracting 20% would have given the wrong answer
• Markup and margin, side by side. cost 100 with a 50% markup tells you to sell at 150, and that this is a 33.3% margin, not 50%
• And percentage changes both ways — 80 to 100 is +25%, but getting back down again takes −20%, not −25%

v0.77 · 27 July 2026

• The currency converter now shows the rate history — 30 days, 90 days, a year or five — so you can see which way it has been moving rather than just today’s number
• It tells you the high, the low and the dates, plus how much the rate has moved over the period
• It remembers what it has already fetched, so flicking between ranges is instant
• And it is honest when offline: the chart says so, and reminds you the conversion still works from the saved rate

v0.76 · 27 July 2026

• The wire calculator now works in mm² as well as AWG — so it is finally usable outside North America, with UK and European cable sizes, ampacities and the matching voltage-drop limits
• Switching to metric moves the defaults with it, to 230 V and metres, rather than leaving you to change three things by hand
• The cable table no longer drags the whole page sideways on a phone — it scrolls on its own, and the last column is reachable again

v0.75 · 27 July 2026

• Rent vs Buy was unfair to renting. It invested the deposit but ignored the money a renter saves every month by not owning — about $600 a month in the default case, and nearly $47,000 over seven years. Both sides now invest whatever they save
• You can now set the buying and selling costs (stamp duty, agent fees) and the insurance, instead of them being fixed behind the scenes
• Trigonometry now solves any triangle, not just right-angled ones — give it any three measurements and it finds the rest
• And it handles the tricky case honestly. Sometimes two completely different triangles fit the same three measurements; most calculators show one and say nothing. This one draws both and tells you why

v0.74 · 27 July 2026

• Twelve calculations instead of five — including the ones people actually get wrong: taking VAT back out of a total, undoing a discount, and the difference between markup and margin
• It shows its working. Every answer comes with the arithmetic written out line by line, so you can check it by hand
• Every calculation now has a picture — a bar for a part of a whole, before-and-after bars for a change, a stacked bar for what a total is made of
• A hundred squares, because that is literally what “per cent” means — shaded in to match your number
• New: percentage points vs percent, percentage error, and two percentages applied one after the other (20% off then 10% off is 28% off, not 30%)

v0.73 · 27 July 2026

• Your favourites and the popular list now come first on the home page, with the live demos below them
• Worked stories are now “Chain Reactions” — because that is what they are: one answer sets off the next. Old links still work
• New tool: Screen Size & Viewing Distance. Tells you how far to sit from a TV or monitor, and whether you would honestly notice the jump from 1080p to 4K to 8K from where you sit
• It asks about your eyesight, because that changes the answer more than most people expect — and it will tell you when a 1080p screen is already sharper than you can see, which at normal sofa distance is surprisingly often

v0.72 · 27 July 2026

• Fifteen worked stories, up from three — buy a house, get out of debt, cut your energy bill, repaint a room, train for a 10K, wire a workshop, shoot the night sky, move a terabyte, and more
• The buttons carry the numbers with them. Click through from a story and the calculator opens with that story’s figures already filled in — no re-typing. There are 54 of these links across 35 different tools
• Every figure in a story is worked out, not asserted, so a story can never quietly disagree with the tool it sends you to
• A visual thread runs through each story: the tools appear as a connected chain at the top, and a single line runs down the page through the steps
• Pick a theme — money, home, body, build, outdoors, digital — and the index filters to it

v0.71 · 26 July 2026

• Chart labels that were cut off now fit. On the triangle tool one side’s measurement ran off the edge of the picture, and on the altitude chart ten of the seventeen place names were sliced off at both sides — those now wrap neatly instead
• Every button reacts when you point at it or press it. The play and reset buttons had no hover at all, and the option buttons changed colour with a jolt; all of them now respond smoothly, and sliders glow a little as you drag them
• Buttons that are unavailable now look it, rather than just quietly doing nothing
• The icon-only reset buttons can now be read aloud by a screen reader, which they could not before
• All of this stays still if you have asked your device to reduce motion

v0.70 · 26 July 2026

• The 3D view was distorting the solids. The camera sat too close, so the near side of a cube drew almost half again as wide as its far side — which looked like the shape being stretched rather than like depth
• It now uses a straight-on view by default, the kind used in technical drawing: parallel edges stay parallel and the far face of a cube is exactly as big as the near one, so you can compare two faces fairly
• A Perspective button if you want the photographic look instead — useful on the rounder solids, and much gentler than before. Your choice is kept in the share link
• Solids no longer swell and shrink as they spin. They held one size only by accident before; now they hold it properly, and still never run off the edge of the frame

v0.69 · 26 July 2026

• Scroll to zoom on the 3D view. Reset view puts the zoom and the angle back together
• Nothing spills outside its box any more. A big circle used to run off the top and bottom of its frame, some labels dropped below the edge, and the shape buttons pushed past the side of their panel
• A pie slice set to a full circle now draws the whole circle instead of going blank — the number was always right, the picture was not
• The unit-squares animation is smooth at any size. At the top of the slider it was drawing ten thousand tiny squares and crawling; it now stays quick and still tells you the real count
• The parallelogram proof was drawing the wrong shape — it now shows the real cut-and-slide that turns it into a rectangle

v0.68 · 26 July 2026

• Every solid is now in real 3D — drag it to turn it round. Spin it, show or hide the faces and edges, and see its corners, edges and faces counted live
• Watch a solid fold flat. This is a real fold along real hinges, not an effect: stop it half way and you can still turn the half-open shape. When it lies flat, the view turns to look straight at it
• Shapes that cannot be folded flat say so — a sphere genuinely cannot be, which is the same reason no flat map of the world gets everything right
• Thirteen new shapes, twenty-nine in total, including all five Platonic solids, plus rings, pie slices, kites, cones with the tip cut off, and capsules
• Every shape now shows you WHY its formula works, as an animation you can play or scrub: a circle cut into wedges and rearranged into a rectangle, three pyramids filling a cube, a cylinder’s label peeling off flat, and Archimedes’ proof for the sphere

v0.67 · 26 July 2026

• Typing a sum into the search box had never worked on the live site. A security rule that stops this site running code from text — a rule worth keeping — was also stopping the calculator, and it failed silently rather than saying so
• It now works out the answer itself rather than asking the browser to run it, so it is both safe and correct: 5x5, 10/3, 2(3+4), 2^10, 10 mod 3, sqrt 2, ln(e), pi
• Nothing was loosened to make this work. The site’s security settings are unchanged

v0.66 · 26 July 2026

• 5x5 used to answer 3,125. It now answers 25. Writing × as the letter x was being read as “to the power of”
• 10 mod 3 answered nothing at all — same cause. Now 1
• Dividing by zero says so instead of leaving you with a blank box
• pi, ln(e), sin(pi) and friends now work, alongside the arithmetic, brackets, powers and roots that already did

v0.65 · 26 July 2026

• If the new search bar did nothing for you, this is why. The site stores a copy of its own code on your device to load fast. It was handing you the newest page paired with yesterday’s code — and the two could not talk to each other
• It quietly fixed itself if you reloaded, which is exactly what made it so easy to miss
• The files that have to match the page are now always fetched fresh. Fonts and icons still load instantly from your device, so nothing got slower
• The build now refuses to ship if those two lists ever disagree again

v0.64 · 26 July 2026

• The search box now answers. Type 300k mortgage at 4.5% over 25 years and the monthly payment appears right there — no page load
• Nine tools answer inline, five of them new to search: paint coverage, running pace, BMI, electrical circuits and concrete mix. So paint for a 4x5 room gives you litres and tins on the spot
• Every answer opens prefilled — click through and the tool already has your numbers in it
• It copes with bad spelling. morgage finds the mortgage calculator, and adds the rate rules worth knowing
• Vague queries still land. A single word brings back the tools, the section and the rules of thumb that match, plus examples to try

v0.63 · 26 July 2026

• Air resistance, on by default — real drag on the bobs, so a swing gradually dies away instead of running forever
• The air density drifts very slightly, on a rhythm that is different every time and never shown. Because a double pendulum is chaotic, that is enough that no two runs are ever quite the same, exactly as in a real room
• Disturbance is now a 1–10 dial instead of a vague number, still off by default
• A random start button — new angles, straight into motion. The quickest way to see two near-identical starts end up nowhere near each other

v0.62 · 26 July 2026

• The new homepage question box was showing up but doing nothing — its code had ended up inside a leftover button handler that no longer existed, so it never ran. It now answers as you type, the example buttons work, and it opens the tool with your numbers in it

v0.61 · 26 July 2026

• Type a question on the homepage and get an answer. “15% of 84”, “300k mortgage at 4.5% over 25 years”, “saving 200 a month at 7%”, “20 kg to lbs”
• And it opens the tool with your numbers already in it — no retyping into an empty form. Anything it cannot parse still takes you to the closest tool
• Fixed a bug where shared mortgage links lost their interest rate and term

v0.60 · 26 July 2026

• Some field-note cards on the compound interest and mortgage pages were showing boxes reading “undefined”. The new cards had been written in the wrong format for those two pages. Fixed, and the site build now refuses to ship a card in the wrong format again

v0.59 · 26 July 2026

• Charges are now modelled properly, and reported as what they cost rather than what you pay. On the default plan a 1% annual charge takes about 11,000 in fees — and leaves you roughly 19,000 worse off, because the money taken would have compounded too
• Contributions that grow. Nobody pays in the same amount for thirty years, and assuming they do quietly understates the result
• Save a scenario and compare. Change the rate, the fee or the horizon and see both curves at once — on a scale that holds still, so adding a comparison never redraws the others smaller
• The crossover year — when growth first outpaces everything you put in that year. On the default plan, year seven. A 1% charge pushes it to year nine
• The rate slider now shows what actually returns what: cash, inflation, bonds, global and US equities

v0.58 · 26 July 2026

• Pick your market and the maths changes — United States, United Kingdom, Canada, Australia, the Eurozone or the Netherlands. Not a currency swap: the whole model moves
• Fixed rates that revert. Outside the US you fix for a few years and then take whatever rates have become. The payment now steps up at the right month instead of pretending your first rate lasts 25 years
• Insurance that works the way yours does. American PMI stops once you are 20% in; Canadian and Australian premiums are added to the loan and you pay interest on them for decades
• Stamp duty, transfer taxes and closing costs, with first-time buyer relief where it exists — and a cash-needed-on-day-one figure
• The affordability test your lender actually uses — loan-to-income in Britain, debt-to-income in America, and the rest

v0.57 · 26 July 2026

• The range is now 200 yards wide with 50-yard markings in both the top-down and 3D views, and the top-down view is taller with distance labels along it
• The markers under the sliders finally line up. Two things were wrong at once: they were positioned for a smaller slider handle than the one actually used, and the browser was quietly drawing a second set of its own ticks underneath
• The reference-flight toggles now sit on one tidy row instead of dropping one onto the next line, and the “all balls fly” switch has moved off the chart selector at the bottom, where it did not belong
• Reference shots stay dotted unless you ask them to fly

v0.56 · 26 July 2026

• The sliders now fit the club. Backspin used to run to 11,000 rpm whatever you had loaded, so you could give a driver wedge spin. Each slider now covers that club’s human range with a bit of headroom — a driver spins 2,050–3,950
• A new Shot shape section with aim (where you start it) alongside spin axis (how it curves), and a tick on each for whether the reference shots copy it
• An all-balls-fly toggle, separate from choosing which levels to show — leave the references as dotted lines, or watch every one of them fly
• The range width no longer stretches to fit the shot, so a hook and a straight one are drawn on the same scale — and the markers under the sliders now line up properly

v0.55 · 26 July 2026

• Every launch slider now shows where each standard of player sits — ball speed, launch angle and backspin all carry a light coloured tick per level, and they move as you change club, because a tour 7-iron and a tour driver are nowhere near each other
• The same marks appear on the standard-of-player slider, with a key naming the colours
• One colour language throughout. The four level colours now mean a skill level and nothing else; your own shot is a single distinct colour in every view. Previously your ball was drawn in the same cyan as “average amateur” in one panel and the same amber as “club pro” in another

v0.54 · 26 July 2026

• The page said “no drag”. That heading belonged to the projectile tool next door — the golf simulator models drag and lift, and now says so
• All the reference balls fly together. Tick any levels and watch their shots leave the tee alongside yours, with a legend naming each and its distance. Playback waits for the slowest ball to land
• A show all / clear all toggle for the levels
• The standard-of-player slider no longer shifts under your cursor as the label beside it changes length

v0.53 · 26 July 2026

• The views no longer rescale. Every shot is drawn on the same fixed 400-yard scale, so a wedge looks like a wedge next to a driver and a change in carry looks like a change. The top view has width markings, and the 3D range uses the same fixed box
• A standard-of-player slider at the top, notched from average amateur through to tour with steps in between — it sets the average ball speed, launch and spin for whichever club you have loaded
• Reference ball flights. Tick any combination of levels and see their shots drawn alongside yours, in all three views, under your conditions
• A landing bug is fixed. The descent angle was being read off a rounded-down sample rather than the ball’s actual velocity, so it jumped between 3° and 39° for near-identical shots — and the bounce inherited the noise. Descent now sits at a steady 40° for a driver, and roll behaves

v0.52 · 26 July 2026

• The play button icons were invisible. A stylesheet rule meant for chart backgrounds was painting a dark plate over every icon in every simulator. Play, loop and pause now actually show
• The bounce and roll-out were badly wrong. A tour driver ran four yards with a nine-inch hop; it now runs eighteen, a 7-iron twelve, and a wedge into a green checks up in two. Backspin now grips the turf on landing, which is what makes those three behave differently
• The 3D range can be moved. Drag to orbit, or use the rotate, elevation and zoom controls. The view now auto-frames the whole shot, so nothing gets cut off at any angle
• Distributions for five metrics — total distance (the new default), carry, ball speed, backspin and launch angle
• A Defaults button to put every setting back

v0.51 · 26 July 2026

• Tell it one club, get your whole bag. Dial in your ball speed and spin for a club you know, and every other club is estimated from it — a 7-iron at 100 mph gives you a 210-yard driver and a 141-yard 6-iron
• See where you stand. Your speed plotted against average amateur, low handicap, club pro and tour distributions, with your percentile against each
• The bounce is finally visible. It was always simulated, but a five-inch hop next to a 36-yard apex was two pixels tall. There is now a landing view on its own scale, with every pitch mark and the roll-out
• A 3D driving range view, and the three clubs that were missing from the bag — 3-iron, 5-iron and gap wedge
• Play, loop and pause buttons now show their own icon on every simulator

v0.50 · 26 July 2026

• Turning motion off now actually stops things. Every animating page respects the setting — except the timers, where stopping the countdown because you dislike animation would be absurd
• Small grey text is now readable. The secondary label colour failed the contrast standard on panel backgrounds; it and its partner tone were re-tuned so the hierarchy between them survives
• Six sources now name a real book. “Any introductory textbook” is not a citation you can follow, so those have been replaced with the actual references

v0.49 · 26 July 2026

• The last fifteen charts gained a “view data as table” panel. Where a table made no sense — a diagram, or a page that already had one — we left it alone rather than pad the count
• Some of these are more useful than the chart: the pendulum now shows how far the small-angle rule drifts as you swing wider, the ramp shows the exact angle where things start to slide, and bolt torque prices the same clamp force for every lubrication condition

v0.48 · 26 July 2026

• Twelve more “view data as table” panels — now on 37 of 69 tools. The engineering simulators are the big win: beam shear and moment along the span, gear ratios stage by stage, thermodynamic state points, Δv by rocket stage, orbital elements
• Nicer touches: the BMI chart’s bands now read as the actual weight range at your height, and the salary waterfall lists every deduction as a share of gross

v0.47 · 26 July 2026

• Twelve more charts gained a “view data as table” panel — the numbers behind the picture, ready to copy, and reachable with a screen reader. Now on 25 of 69 tools
• Among them: equivalent race times at other distances, voltage drop by cable run, bearing life against load, RAID levels side by side, and the normal distribution by z-score

v0.46 · 26 July 2026

• Every calculator now says what it assumes — and therefore where it stops being right. Eight tools were missing that; the rest already had it
• Charts are starting to carry a “view data as table” panel, so you can read the actual numbers, copy them out, or reach them with a screen reader. Nine more this time, including the mortgage-style yearly breakdowns on car finance, FIRE and rent vs buy

v0.45 · 26 July 2026

• The percentage, data transfer, currency and resistor colour code tools were the four thinnest on the site. Each now has field notes, a worked example, and a plain statement of what it assumes
• Genuinely useful things, not padding: why ±10% leaves you 1% down, why stacked discounts never add up, why there is a 4.7kΩ resistor but no 5kΩ, and why you should always decline the card machine’s offer to charge you in pounds

v0.44 · 26 July 2026

• The shared code every page loads was doing all its work before the page was allowed to draw. It now waits its turn: about 60% less code blocks the first paint, on 186 pages
• Nothing looks or behaves differently — same features, same bytes, just a better order. Shared links, saved units and currency, and the dark/light theme all still apply immediately

v0.43 · 26 July 2026

• New logo: a thumbprint whose outer ridge runs out and plots a data point — thumb to number, which is rather the idea here
• Used everywhere: homepage, browser tab, and the home-screen icon if you install the site

v0.42 · 26 July 2026

• New tagline: the numbers you keep looking up — the previous one talked about how the site is built rather than what it saves you
• Simpler homepage mark: just the ≈, matching the icon used everywhere else

v0.41 · 26 July 2026

• On the homepage ball-and-beam demo the ball used to stop dead against an invisible limit. It now falls off the beam when it runs out of beam, as it would in reality
• The “underdamped” setting was actually unstable — it diverged, and the invisible limit was hiding that. Retuned so it overshoots and rings but settles
• The full Ball and Beam simulator already handled this correctly and is unchanged

v0.40 · 26 July 2026

• Every calculator’s page title now names what makes it different — “Mortgage Calculator — PMI, extra payments & schedule” rather than just “Mortgage Calculator”
• Taken from each tool’s own description, so nothing new is claimed

v0.39 · 26 July 2026

• Every rule page is now titled with the question it answers — “How long does a 1 metre pendulum take to swing?” rather than “A metre swings in two seconds”
• The memorable version still heads the page; the question makes it findable
• Each page now answers its question directly, and marks it up so search engines can show it

v0.38 · 26 July 2026

• Fixed a header that was telling Google not to read the sitemap — so only 19 of 186 pages had been discovered
• The Rulebook’s 96 rule pages and most calculators should now start appearing in search

v0.37 · 26 July 2026

• New tagline: approximately right, precisely sourced — a fast estimate you can trust, because the working is shown
• The ≈ mark from the favicon now appears on every page; several were still using an older, unrelated logo
• Clearer page title and description, naming what the calculators actually do

v0.36 · 26 July 2026

• New pause control in the toolbar — stops the moving diagrams and the rotating homepage demo, and remembers your choice
• Animations across the whole site now respect your device’s reduce motion setting, not just some of them
• More of this to come: results still change silently for screen readers, which is next

v0.35 · 25 July 2026

• New Contact & corrections page — report a wrong figure, an out-of-date source, an accessibility problem, or a privacy request
• An email address is optional. An anonymous correction is just as useful
• Your IP is not stored with the message, and submissions are deleted after 180 days — see Privacy §2b
• Works without JavaScript, and if it can’t send it says so rather than pretending it worked

v0.34 · 25 July 2026

• The Rulebook now lists each discipline once for search engines and readers without JavaScript — eight of them were repeating
• The homepage totals are in the page itself instead of counting up from zero, so the numbers are right the moment it loads
• Both were invisible in a normal browser and only affected people or crawlers without JavaScript

v0.33 · 25 July 2026

• Tools whose method is country-specific now say so, above the inputs — before you type anything
• The mortgage and rent-vs-buy calculators use US conventions (PMI, property tax as a percentage of value); wire gauge follows NEC; stud and fixing sizes follow UK guidance
• Showing your currency symbol never made a calculator right for your country — this makes the difference explicit
• Tools that are the same everywhere (physics, maths, ISO standards) carry no label, so the label means something where it appears

v0.32 · 25 July 2026

• Cleaner section headings on every tool page — the same quiet style throughout, instead of coloured badges and marker bars
• The walkthrough section is now called How it works everywhere (it was split between two names)
• Added the results are for reference only note to eight tools that were missing it, including the electrical and fixings calculators
• Consistent British spelling across the site

v0.31 · 25 July 2026

• Money tools now show your currency symbol — £, €, $, CA$, A$ or ₹ — picked up from your browser, or set it yourself from the toolbar
• This changes the symbol only: the numbers you type are never converted. For real conversion use the Currency Converter
• Tip Calculator keeps its own per-bill currency picker, now starting from your site-wide choice
• Salary and Energy Cost still show each country's own figures, since those symbols are part of the data

v0.30 · 25 July 2026

• Every rule of thumb now has its own page — 96 of them, each with the rule, why it works, and the calculator that does it exactly
• Rules are shareable: each one gets its own preview card when you post the link
• Search understands typos and phrasing — “morgage”, “presure drop”, “dewpoint”, “how much paint” now find the right thing
• Light theme meets WCAG AA contrast across every area colour
• Four tools split out of bigger ones: Currency Converter, Percentage Calculator, Resistor Colour Code, Data Transfer Time
• 69 tools · 96 rules of thumb

v0.29 · 25 July 2026

• Replaced template placeholders on Privacy and Terms; Terms §7 matches self-hosted fonts
• Added About and this public Changelog
• Car Finance Calculator — UK hire purchase / PCP and US auto loans
• Slider track fill stays under the thumb site-wide
• Build pipeline keeps tool/rule counts honest; prerenders /tools and /rulebook for no-JS crawlers
• 65 tools · 92 rules of thumb

v0.28 · July 2026

• Homepage live demos (pendulum, spring, cradle, ball-and-beam, golf)
• Thumbprint map polish; worked Stories; shareable result snapshots
• Deep overhauls: unit converter, mortgage, BMI, tip, compound interest, TDEE, salary, time zone, speed test, feels-like
• Favourite star + popular ranking (Cloudflare Worker + KV)

v0.27 and earlier · July 2026

• Flagship “wow” scenarios on cinematic simulators
• Shared tool chrome, self-hosted fonts, Rulebook-first content focus
• Area split Engineering → Mechanical / Electrical; Environmental rename