Torque / Power / RPM Calculator
This tool lets you calculate one of torque, power, or RPM based on the other two. Enter values and press 'Calculate'.
Torque, power, and RPM are crucial parameters for understanding the performance of engines and motors. This tool allows you to calculate and convert between these values.
You can calculate output from torque and RPM, or determine RPM from power and torque. Conversions between different units such as kW, PS, and hp are also supported.
What’s the Difference Between Torque and Horsepower?
Torque is the force that causes rotation, while horsepower is the rate of work done by that torque at a given rotational speed. Using a bicycle as an example: pushing hard on the pedals uphill represents torque, spinning fast represents RPM, and their product is horsepower.
Engine power can be calculated using the following formula:
Even with the same torque, a higher RPM results in greater power output.
| Term | Meaning | Units |
|---|---|---|
| Torque | Rotational force | Nm, kgf·m |
| Power (Horsepower) | Amount of work per unit time | kW, PS, hp |
About the Power Calculation Formula
Engine power (in kW) can be calculated from torque and RPM using the following equation:
P [kW] = (2π / (60 × 1000)) × R [min⁻¹] × T [Nm]
The variables in this equation represent:
- P: Power (in kilowatts)
- R: Rotational speed (per minute, RPM)
- T: Torque (in newton-meters)
The constant part is approximately:
2π / (60 × 1000) ≈ 0.00010472
In short, even with the same torque, increasing RPM results in higher power.
Go to the Engine Displacement Calculator
If you don't know your engine's displacement, you can easily calculate it using our displacement calculator. Just enter bore, stroke, and cylinder count.