You enter torque in pound-feet and engine speed in RPM. The tool applies the standard mechanical horsepower formula — HP = (Torque × RPM) ÷ 5,252 — then converts to kilowatts by multiplying by 0.7457. It assumes steady-state output at the given RPM and does not account for drivetrain losses, altitude, or temperature corrections.
It derives from unit conversion: one horsepower is 33,000 ft-lbs per minute, and torque is measured in ft-lbs. Dividing 33,000 by 2π gives approximately 5,252, which reconciles the rotational speed (RPM) with the linear work definition.
This calculator computes brake horsepower (BHP) — the power measured at the engine's crankshaft. Wheel horsepower is typically 10–20% lower due to drivetrain friction losses through the transmission, differential, and axles.
Yes, the formula works for any rotary motor. Electric motors produce peak torque at 0 RPM and maintain it across a wide speed range, so the power curve looks different from a combustion engine but the math is identical.
Check the vehicle's spec sheet or owner's manual for peak torque. For real-time readings, an OBD-II scanner connected to your car's diagnostic port can display live torque and RPM data.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.