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Wind calculators
Estimate how much power a wind turbine makes from its rotor size and your wind speed.
New to the topic? Read Wind Energy: How Wind Turbines Work and What They Produce.
FAQ
Frequently asked questions
How do you calculate wind turbine power?
Power equals one half times air density times the rotor swept area times wind speed cubed times the power coefficient (P = ½ρAv³Cp). At sea level air density is about 1.225 kg per cubic meter, and real turbines reach a Cp of roughly 0.25 to 0.45.
Why does wind speed matter so much?
Power rises with the cube of wind speed. Doubling the wind speed gives eight times the power, so a site averaging 6 m/s produces about 70% more energy than one averaging 5 m/s with the same turbine.
What is the Betz limit?
The Betz limit is the theoretical maximum share of the wind’s kinetic energy any turbine can capture: 16/27, or 59.3%. Commercial turbines typically achieve 35–45%, and small turbines less.
What wind speed do I need for a home wind turbine?
A small turbine generally needs an average wind speed of at least about 4 to 5 m/s (9 to 11 mph) at hub height to be worthwhile. Check local wind data and mount the turbine well above nearby obstacles.
How much energy does a small wind turbine make in a year?
It depends mostly on rotor size and average wind speed. A 3 m rotor at a 5 m/s average site produces about 3,200 kWh a year at a Cp of 0.35 under ideal assumptions; real output is usually lower because of cut-in speeds, turbulence and downtime.
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