United States calculator
Convert wheel horsepower and crank horsepower
Convert wheel horsepower to estimated crank horsepower—or crank horsepower to wheel horsepower—using an editable drivetrain-loss percentage.
Drivetrain loss • forward/reverse conversion
Calculator inputs
WHP to Crank HP Calculator results
How this WHP to Crank HP Calculator works
Wheel horsepower equals crank horsepower multiplied by one minus drivetrain loss. Reverse conversion divides wheel horsepower by that retained fraction.
Important: Drivetrain loss is not a fixed universal percentage and varies by vehicle, dyno, temperature, tire and test method.
What assumptions should I verify?
Verify every entered quantity, rate, unit, product specification and local requirement before relying on the estimate. U.S. conventions are primary where location matters.
Is information sent anywhere?
No. Calculations run locally in the browser and this calculator sends no entered information to a remote service.