Skip to content
Calculator Tools
Wind Energy Calculators

Turbine Efficiency Calculator

Overall efficiency of a wind turbine against the theoretical power in the wind and the Betz limit.

Enter values

Results update as you type.

Result

Power coefficient (Cp)

0.5413

Overall efficiency
54.13%
Power available in the wind
2,216.7 W
Betz limit output
1,314.5 W
Share of the Betz limit reached
91.3%
Rating
Excellent — near the practical maximum

About the Turbine Efficiency Calculator

Overall efficiency of a wind turbine against the theoretical power in the wind and the Betz limit.

Also known as: power coefficient calculator, cp calculator, wind turbine efficiency.

How to use this calculator

  1. Enter measured electrical output, rotor diameter, wind speed, air density.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Cp = measured output ÷ (½ρAv³)

Worked example

Using the values pre-filled in the calculator above:

  • Measured electrical output = 1,200 W
  • Rotor diameter = 3 m
  • Wind speed = 8 m/s
  • Air density = 1.225 kg/m³

the calculator returns:

  • Power coefficient (Cp): 0.5413
  • Overall efficiency: 54.13%
  • Power available in the wind: 2,216.7 W
  • Betz limit output: 1,314.5 W