Earth & Energy calculators
Questions about the weather and about resource use have something in common: they combine a few measurements into a single figure that is easier to act on. These calculators work out how hot it feels, what an appliance costs to run, how much a solar array might produce, or how much carbon a trip adds.
Each estimate uses the figures you enter and states the factors it assumes, such as a grid emissions rate or a panel efficiency, so two options can be compared on the same basis.
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- Electricity Cost CalculatorEstimate what an appliance costs to run per day, month and year from its watts (or amps and volts), hours of use and your price per kWh.
- Carbon Footprint CalculatorSee roughly how much CO2 your household puts out each year from electricity, home heating, driving and flights, using US EPA figures you can adjust.
- Dew Point CalculatorFind the dew point from the air temperature and relative humidity, or the relative humidity from a dew point, using the Magnus formula.
- Drip Faucet CalculatorTurn a dripping tap's drips per minute into the water wasted per day, month and year, in liters and gallons, and what it costs.
- Flight Emissions CalculatorEstimate how much CO2 your flight puts out, from its distance or two airport locations, your seat class and an emission factor you choose.
- Heat Index CalculatorSee how hot it really feels from the air temperature and humidity, using the US National Weather Service heat index method.
- Lighting Energy Savings CalculatorSee how much energy, money and CO₂ you'd save each year by swapping old bulbs for LEDs, and how quickly the new bulbs pay for themselves.
- Rainwater Harvesting CalculatorEstimate how much rainwater a roof can collect from its area, the rainfall and a collection efficiency, with a tank size for one large storm.
- Solar Panel CalculatorSize a solar system from your electricity use and count the panels it needs. Or estimate what a given system makes in a year.
- Solar Payback CalculatorSee how many years home solar takes to pay for itself, plus its size, cost and yearly savings, from your power use, sunshine and prices.
- Wind Chill CalculatorFind how cold it feels on bare skin from the air temperature and wind speed, using the 2001 North American wind chill index.
- Wind Turbine CalculatorEstimate how much power a wind turbine makes from its rotor size and the wind speed, plus the most any rotor could catch and a yearly total.