Engine Horsepower Calculator

Calculate engine horsepower based on torque and RPM measurements, or estimate horsepower from your vehicle's specifications.

Reviewed August 29, 2026 · Calculation methodology · Inputs stay in your browser

Enter the measured torque.
Enter the engine RPM at which torque was measured.
Enter your engine's displacement.
Select your engine's induction type.
Select the number of cylinders in your engine.
Select your engine's approximate efficiency level.

Understanding Horsepower

  • Horsepower = (Torque × RPM) ÷ 5,252 (when torque is in lb-ft)
  • 1 horsepower (HP) equals approximately 0.746 kilowatts (kW)
  • Peak horsepower and peak torque typically occur at different RPMs
  • Modern engines often produce 70-100 HP per liter of displacement in naturally aspirated form
  • Forced induction (turbocharging/supercharging) can significantly increase horsepower output

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