Wind Turbine Output Calculator

Power is proportional to wind speed cubed in this formula, so doubling wind speed multiplies power by 2³, or 8 times — going from 5 m/s to 10 m/s at the same rotor and efficiency turns a modest output into a much larger one. This cubic relationship is why turbine siting, hub height, and even small differences in average site wind speed matter so much more than they might first appear.

The Betz limit is the theoretical maximum fraction of wind's kinetic energy any turbine can extract — 59.3% — because some airflow must keep moving past the rotor for the turbine to keep working at all. The Cp input caps at 59 here to respect that physical ceiling, and real utility-scale turbines typically run their Cp in the 35-45% range under normal operating conditions, well short of the theoretical maximum.

The calculator uses a single average wind speed throughout rather than integrating power across the full distribution of wind speeds a site actually experiences over a year. Because power scales with the cube of speed, gustier high-speed periods contribute disproportionately more energy than the average alone suggests, so a single-average calculation like this one will generally underestimate real-world annual production compared to a Weibull-based assessment.

Swept area treats the spinning blades as tracing a circle, computed as π times the radius squared, where radius is half the rotor diameter you enter. This is the disc-shaped cross-section of air the rotor intercepts, and it's the area term multiplied directly into the power equation — a larger rotor captures proportionally more wind at the same wind speed.