Convert torque and engine RPM into horsepower, kilowatts and metric PS.
How the horsepower calculator works
Enter torque in pound-feet and engine speed in RPM and this calculator returns horsepower, plus the equivalent in kilowatts and metric PS.
It uses the standard relationship between torque, speed and power.
Worked example
On the values this calculator opens with, the horsepower is 285.6. Underneath, Kilowatts comes out at 213 kW and Metric PS at 289.6 PS. Change any field and every figure updates as you type.
Using the calculator
- Enter the torque in lb-ft.
- Enter the RPM.
- Read the horsepower and equivalents.
The formula
horsepower = torque × RPM ÷ 5252
FAQ
How is horsepower calculated from torque?
Multiply torque (lb-ft) by RPM and divide by 5,252 — the constant where torque and horsepower curves cross.
What’s the difference between hp, kW and PS?
They’re different units of power: 1 hp ≈ 0.746 kW ≈ 1.014 PS (metric horsepower).
Why 5252?
It comes from the definition of horsepower and the conversion between RPM and radians per minute.