How it works
A walkthrough, end to end.
- 1
Pick a mode: torque + RPM, or unit conversion.
- 2
Enter the values; the calculator returns HP, kW, and PS.
- 3
Useful for engine specs and motor sizing.
Reference
Horsepower
HP = (torque [lb-ft] × RPM) / 5252. 1 HP = 0.7457 kW = 1.0139 PS.
Use cases
What you can do with this.
Engine specs
Translate dyno torque/RPM to peak HP.
EV motor compare
Convert kW ratings to HP.
Tractor/PTO
Quick PTO HP from torque test.
Boat motor
Compare prop curves.
Motorcycle
Convert metric horsepower (PS) to HP.
FAQ
Frequently asked.
It comes from 33,000 ft-lb/min ÷ 2π. HP and torque equal numerically at 5252 RPM.
Mechanical (US) = 745.7 W. Metric PS = 735.5 W (~1.4% smaller).
No. All math runs in your browser.
Drivetrain loses 10–15%; this calculator computes engine-level HP.