Unit Converters

Torque to Horsepower (HP from Torque and RPM)

Enter engine torque and the RPM it is measured at, and you get horsepower, and you can solve the other way too. Power and torque always cross at 5,252 RPM, where the two numbers are equal.

How to use
  1. Enter the torque value and choose lb-ft or N·m.
  2. Enter the engine speed in RPM.
  3. Switch the mode to find torque from a known horsepower.
Examples
Horsepower
300.0 HP

at 5,252 RPM with 300.0 lb-ft of torque

Power
300.00 HP
Kilowatts
223.71 kW
Torque (lb-ft / N·m)
300 / 406.7
Engine speed
5,252 RPM
Conversion factors are exact; rounding may affect the final digit.
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Worked examples

TorqueRPMHorsepowerNote
300 lb-ft5252300 HPPower equals torque at 5,252 RPM
300 lb-ft3000171 HPBelow the crossover, torque reads higher
200 lb-ft6000228 HPAbove the crossover, HP reads higher
400 N·m4000224 HPMetric torque input

Common questions

Why is 5,252 RPM special?

At 5,252 RPM the horsepower and lb-ft torque numbers are always equal, because that is where the unit constants cancel out. Below it torque is the larger number, above it horsepower is.

What is the formula?

Horsepower equals torque in lb-ft times RPM divided by 5,252. For metric, use kW = N·m × RPM / 9,549.

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