Horsepower Calculator

The Horsepower Calculator allows you to calculate power in various units from force, distance, and time. Automatically converts between watts, horsepower (HP), metric horsepower (PS), kilowatts, BTU/hour, and foot-pounds per second. Includes precise conversion factors, physics definitions, and detailed explanations. Essential tool for engineers, physics students, mechanics, and professionals working with engines, machines, and power systems.

Updated at: 06/15/2025

Formula: Power = (Force × Distance) ÷ Time

Power Definition

Power is the rate of doing work or transferring energy per unit time. It's a fundamental measure in physics and engineering.

Common Units:

  • Watt (W): SI unit of power, equals 1 joule per second
  • Horsepower (hp): Traditional unit, originally based on the power of horses
  • Metric HP (PS): Metric horsepower, used mainly in Europe

Conversion Factors

Power Conversions:

  • 1 hp = 745.7 W
  • 1 PS = 735.5 W
  • 1 kW = 1000 W
  • 1 W = 3.412 BTU/h
  • 1 W = 0.737 ft⋅lbf/s

Important Notes

Work vs Power: Work is energy transferred, power is the rate of that transfer. Same amount of work can be done with different powers.

Horsepower History: The term was created by James Watt to compare steam engine power with working horses.