Power, Torque & Speed
RPM from Power and Torque Calculator
Enter mechanical power and torque to solve for the corresponding shaft speed in revolutions per minute.
Inputs
Formula
Rotational speed from power and torque
Worked example
Using the default values shown in the calculator, the same formula gives the following result. This is a quick sanity check for the calculation, not a design recommendation.
Inputs
- Mechanical power
- 7.5 kW
- Shaft torque
- 49.4 N*m
Result
- Shaft speed
- 1,449.8 rpm
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Frequently asked questions
What power value should I use?
Use the mechanical power at the same shaft where the torque applies, unless you explicitly account for efficiency losses.
Why does RPM increase when torque decreases at fixed power?
For constant mechanical power, torque and angular speed are inversely related.