Horsepower Calculator

Horsepower from torque and RPM

• Horsepower = torque (lb·ft) × RPM ÷ 5252 — the classic SAE relationship.
• At 5252 RPM, torque (lb·ft) and horsepower are the same number.
• Toggle lb·ft / N·m and hp / kW to match the units on your dyno sheet or OEM chart.

Torque tells you twisting force; horsepower tells you how fast that work is being done. This free horsepower calculator turns a torque figure and an engine speed into brake power so you can compare cams, estimate a swap, or reverse-check a dyno printout.

Enter torque and the RPM where it was measured. The dyno-cell view shows horsepower with torque and engine speed alongside. Feed crank torque for crank HP, or wheel torque if you want an approximate wheel figure — the math does not invent drivetrain loss for you.

Pair this with the torque calculator when you only have an HP number, and with gear ratio or RPM-at-speed tools when you need to see how that power lands on the road.

How to use the horsepower calculator

1. Enter torque. Use the peak or the RPM point you care about, in lb·ft or N·m.
2. Enter engine RPM. Match the RPM where that torque was measured or estimated.
3. Read horsepower. The dyno cell shows horsepower (and kilowatts) at that operating point.

Horsepower FAQ