Torque to HP Calculator
Find horsepower from torque and RPM.
Convert engine torque and speed into horsepower.
How the Math Works
The Torque to HP Calculator uses the fundamental relationship between rotational force and power. The formula hp = torque × RPM ÷ 5252 converts torque (measured in pound-feet) and rotational speed (RPM) into horsepower. The constant 5252 comes from the conversion factors between units: 5252 equals 33,000 foot-pounds per minute divided by 2π radians per revolution. This formula reflects that horsepower measures work per unit time, while torque measures rotational force. When you multiply torque by RPM, you're essentially calculating the total rotational work done per minute, which must then be divided by 5252 to convert to the standard horsepower unit.
Practical Applications
This calculator is essential for automotive engineers, mechanics, and performance enthusiasts when evaluating engine specifications. For example, if an engine produces 350 pound-feet of torque at 6,000 RPM, the calculation 350 × 6000 ÷ 5252 equals approximately 399 horsepower. This helps determine if an engine meets performance requirements for specific applications like racing, towing capacity assessments, or comparing different engine options. Mechanics can use it to verify manufacturer claims or diagnose potential engine issues when actual performance doesn't match expected outputs.
Day-to-Day Use
Understanding this relationship helps consumers make informed decisions when purchasing vehicles or upgrading automotive components. When shopping for a car, you can use this calculation to compare engines that might have different torque and RPM ratings on paper, giving you a clearer picture of real-world performance. Whether you're choosing between a diesel truck engine and a gasoline one, or evaluating if a motorcyclist's engine has sufficient power for highway merging, this calculation bridges the gap between technical specifications and practical performance expectations you'll experience driving the vehicle.
Worked example
300 lb-ft at 5000 RPM → 285.6 hp.
FAQ
Why 5252?
It falls out of the unit conversion — hp and torque always cross at that RPM.