Horsepower Calculator
Calculate horsepower from torque and RPM, or solve for torque or RPM given the other two values.
Enter any two values to calculate the third.
How It Works
The relationship between horsepower, torque, and RPM is fixed by physics. Enter any two values to solve for the third. The constant 5252 comes from unit conversion (33,000 ft-lbs/min per HP divided by 2π).
Formula
HP = Torque (lb-ft) x RPM / 5252
Frequently Asked Questions
Why is 5252 used in the horsepower formula?
5252 is the constant that converts RPM and lb-ft torque into horsepower. It equals 33,000 (ft-lbs per minute per HP) divided by 2π (radians per revolution).
At what RPM does horsepower equal torque?
Horsepower and torque always intersect at exactly 5252 RPM. Below 5252 RPM, torque exceeds horsepower; above it, horsepower exceeds torque.