Calculators for where you are on the planet, what the sky is doing there, and what energy costs you — moist-air physics, solar output, dwelling heat loss, and what an electric car actually costs per mile.
What a charge costs and how long it really takes, with the power taper that makes the last 20% the slow 20% — then cost per mile against petrol.
Design heat loss in kW from U-values and ventilation — and how much bigger the radiators must be at a heat pump’s flow temperature.
Humidity, dew point, wet-bulb, and the full moist-air state — with a draggable psychrometric chart and a city climate atlas.
Count the seconds from flash to thunder. The arithmetic is trivial; whether you are already in range, and why silence is not safety, is the part worth knowing.
Wind chill and heat index from the official NWS formulas — the real "feels like" temperature, with frostbite and heat-risk categories.
What time is it there — and when does a meeting in one city land in another? Compare cities side by side across the day.
Annualised output for a solar array — pick a city, system size, panel tilt and orientation, and see month-by-month generation.
The height of tide at any hour and the window you can cross in — with the rule drawn against the true curve, and an honest account of the assumption that actually ruins it.
What each magnitude releases and does, famous earthquakes at every level and the equations behind them — with a world map of 53 years of magnitude 6+ quakes against the plate boundaries.
How fast the published guidance says to come up from a dive, the depth bands from open water to the Challenger Deep, and what a submersible does differently. Reference only.
Sunrise, sunset, solar noon and twilight for any place and day: the sun’s height through the day, its path across the sky and the whole year at a glance.
The Moon’s phase, moonrise and moonset for any place and day, its path across the sky, its distance, the next eclipses and the year’s full moons.
What your appliances actually cost to run. Add common or custom appliances, pick a country, and see the cost per day, week, month or year — plus CO₂.
Every country on one map, in an equal-area or a Mercator projection — with population, GDP, land area and highest points sortable, and continents, NATO, the EU and the G7 highlighted on demand.
Pressure, temperature, oxygen and force from the stratosphere to the ocean floor — jump to Everest, cruising altitude, the Titanic wreck or the Challenger Deep.