Torque to power calculator
Power is torque times angular velocity. The imperial version hides a factor of 5252, which is just the unit conversion.
rpm
Power
125.6637kW
- Power in mechanical horsepower
- 168.5178 hp
- Power
- 125 663.71
- Torque in pound-feet
- 221.2686
- Horsepower by the 5252 rule
- 168.5214
- Angular velocity
- 418.879 02 rad/s
Show the working
- Torque = 300
- Rotational speed = 4000
- Angular velocity = 4000 * 2 * pi / 60 = 418.879
- Power = 300 * 418.879 = 125 664
- Power = 125 664 / 1000 = 125.664
- Power in mechanical horsepower = 125 664 / 745.69987158227022 = 168.518
- Torque in pound-feet = 300 / 1.3558179483314004 = 221.269
- Horsepower by the 5252 rule = 221.269 * 4000 / 5252 = 168.521
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- P = T omega, with omega in radians per second
- hp = torque in lb-ft x rpm / 5252
- 5252 is 33 000 / (2 pi), the conversion from foot-pounds per minute to horsepower.
Torque and horsepower curves always cross at 5252 rpm, for exactly this reason and no other.