Horsepower Calculator
Convert between HP, kW, watts, ft-lbf, N-m, and BTU/hr. Calculate horsepower from torque and RPM.
Power Unit Converter
How this was calculated
1 HP (mechanical) = 745.6999 W = 0.7457 kW = 2,544.43 BTU/hr = 550 ft-lbf/s = 1.01387 PS (metric HP).
Torque formula: HP = Torque (ft-lbf) × RPM / 5,252. Derived from P = 2π×T×N / 33,000.
Torque conversions: 1 ft-lbf = 1.35582 N-m = 12 in-lbf.
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Book a free strategy call →Understanding Horsepower
Horsepower (HP) is a unit of power originally defined by James Watt to compare the output of steam engines with draft horses. One mechanical horsepower equals 550 foot-pounds per second, or about 745.7 watts. In engineering, horsepower is used to rate engines, motors, pumps, and compressors across automotive, industrial, and energy applications.
The relationship between horsepower, torque, and RPM is fundamental to rotating machinery: HP = Torque × RPM / 5,252. This means that at low RPM, high torque is needed to produce significant horsepower, while at high RPM, even modest torque generates substantial power. This relationship is critical when sizing electric motors, selecting pump drives, or evaluating engine performance curves.
All calculations run entirely in your browser. Built by Groundwork Analytics, an AI and engineering company building digital tools for the energy industry.