Power from torque

Engine Horsepower Calculator

Estimate horsepower from torque and engine speed.

Crank, wheel and rated horsepower

The formula is exact for the relationship between torque, rotational speed and power. Real published numbers may describe crankshaft, wheel or corrected dyno horsepower, so compare like with like.

Example

At 300 lb-ft and 5,252 RPM, horsepower is 300 x 5,252 / 5,252 = 300 hp. At the same torque and 3,000 RPM, power is lower because the engine is doing fewer rotations per minute.

Common mistakes

Use lb-ft in the 5,252 formula. If your torque is in newton-meters, convert it first or use the calculator's Nm option.

Limitations

This estimate does not include drivetrain loss, dyno correction factors, air density, battery limits, turbo behavior or how long the engine can sustain the output.

Last reviewed: 2026-05-17

Before relying on this result

Use this calculator together with the formula, assumptions, limitations and examples on the page. If the topic involves health, tax, lending, investment, legal, safety or current-rate decisions, treat the number as an estimate and check the relevant primary source or professional guidance.

Calculator metadata last reviewed: 2026-05-14.