What this calculator does
This tool estimates how much power a wind turbine produces at a given wind speed, and projects that into a rough annual energy output, based on the turbine’s rotor size and a handful of standard aerodynamic and site factors.
How the estimate is calculated
Power available in moving air is found with the formula P = 0.5 x air density x swept area x wind speed cubed x power coefficient (Cp). Swept area comes from the rotor diameter (area = pi x radius squared), and wind speed is cubed because doubling wind speed increases available power eightfold. The power coefficient represents how much of that theoretical energy the turbine actually converts to electricity; the Betz limit caps this at about 59.3%, but real turbines typically achieve 30-45% once mechanical and generator losses are included. The annual energy estimate multiplies the calculated power by 8,760 hours in a year and by a capacity factor, which accounts for the fact that wind speed varies constantly and the turbine won’t run at this exact output all the time.
This is a simplified, single-point estimate — real-world turbine output depends on a full wind speed distribution over the year, turbine cut-in/cut-out speeds, and site-specific turbulence, so use it for general educational or planning purposes rather than a financial or engineering guarantee.