Horsepower Calculator

Horsepower measures the rate at which an engine can do work. It is calculated from torque (rotational force) and engine speed (RPM). This calculator computes horsepower from torque/RPM and converts between different power units used globally.

1. 1

   Enter Torque

   Input torque in lb-ft or Newton-meters

2. 2

   Enter Engine Speed

   Input RPM at which torque is measured

3. 3

   Calculate Power

   See calculated horsepower at that RPM point

4. 4

   View Conversions

   See equivalent power in HP, kW, and PS

• 1

  Peak torque and peak horsepower occur at different RPM points

• 2

  Electric motors produce peak torque from 0 RPM, unlike combustion engines

• 3

  Wheel horsepower is 15-20% less than crank horsepower due to drivetrain losses

• 4

  Higher RPM engines make more power from less torque by spinning faster

• 5

  kW is the international standard; HP is used in US/UK; PS in Europe

• Confusing torque with horsepower - torque is force, power is the rate of applying force

• Using peak torque RPM when calculating power at a different RPM

• Comparing crank horsepower to wheel horsepower directly

• Ignoring that HP and PS are slightly different units