Turn torque and RPM into horsepower in seconds. Free horsepower calculator with crank and estimated wheel HP output — no signup, no downloads.
Estimate engine horsepower from torque and engine speed.
How It Works
This calculator applies the standard torque-to-horsepower formula, HP = Torque × RPM ÷ 5252, converting your engine’s rotational force at a given RPM into a horsepower figure. Just enter your torque (lb-ft or Nm) and RPM, and it instantly shows crank horsepower or an estimated wheel horsepower after accounting for drivetrain loss.
FAQ:
It uses the industry-standard equation HP = Torque × RPM ÷ 5252. The constant 5252 comes from the physics relationship between torque, angular speed, and power, and it’s the same figure used on most dynamometer readouts.
Because of how the formula is derived, torque and horsepower values are mathematically equal at exactly 5252 RPM regardless of the engine. Below that RPM, torque reads higher than horsepower; above it, horsepower reads higher.
Crank horsepower is the raw output measured at the engine itself, before any power is lost to the transmission, driveshaft, and differential. Wheel horsepower is what actually reaches the ground, typically 10–25% lower depending on the drivetrain, which is why this tool includes an adjustable loss percentage.
Yes. Select “Nm” from the torque unit dropdown and the calculator automatically converts it to lb-ft internally before applying the formula, so you don’t need to do any manual conversion.