Earth, sky & time

Environmental

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.

EV Charging & Running Cost

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.

min(charger, car) · p/kWh ÷ mi/kWh
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Heat Loss & Heat Pump Sizing

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.

ΣU·A·ΔT + 0.33nV·ΔT
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Psychrometer

Humidity, dew point, wet-bulb, and the full moist-air state — with a draggable psychrometric chart and a city climate atlas.

RH · dew point · wet-bulb · mixing ratio
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Feels Like Temperature

Wind chill and heat index from the official NWS formulas — the real "feels like" temperature, with frostbite and heat-risk categories.

wind chill · heat index
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Time Zone Converter

What time is it there — and when does a meeting in one city land in another? Compare cities side by side across the day.

UTC offsets · meeting planner
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Solar PV Estimator

Annualised output for a solar array — pick a city, system size, panel tilt and orientation, and see month-by-month generation.

E = A · η · H · PR
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Sun & Moon

Sunrise, sunset, day length and twilight — plus the moon phase and illumination — for any city and date.

sun & moon · any date
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Energy Cost Calculator

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.

watts · kWh · $/£/€ per year
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Altitude & Depth

Pressure, temperature, oxygen and force from the stratosphere to the ocean floor — jump to Everest, cruising altitude, the Titanic wreck or the Challenger Deep.

atm · O₂ · °C · F = ΔP·A
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Results from every tool here are for reference only. Check them against other sources before relying on them for a real decision.