Automotive
Horsepower from torque
Estimate mechanical horsepower from torque and rotational speed.
Calculators / Automotive / Engine power estimate
Engine power estimate calculator
Estimate power from torque in newton-metres and engine speed.
On this page
Mechanical power188.5kW
Metric horsepower256.28PS
Calculator controls
How to calculate
Estimate power from torque in newton-metres and engine speed.
Mechanical power = torque*rpm*2*pi/60/1000; Metric horsepower = torque*rpm*2*pi/60/1000/0.73549875
Worked example
Torque (N·m): 400; Engine speed (rpm): 4500.
Mechanical power: 188.5 kW; Metric horsepower: 256.28 PS.
Assumptions and limits
This computes power from measured torque and speed; it does not predict torque from engine displacement.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate power from torque in newton-metres and engine speed. The displayed figures use the inputs and formula shown on this page.
When this tool is useful
Use the engine power estimate to compare a scenario, check an estimate, or verify a manual calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Torque (N·m) | Enter a number of at least -1000000000 and no more than 1000000000. |
| Engine speed (rpm) | Enter a number of at least 0 and no more than 100000. |
Frequently asked questions
What should I check before using the engine power estimate result?
This computes power from measured torque and speed; it does not predict torque from engine displacement.
Is this engine power estimate result exact?
It is exact for the stated mathematical model and entered values. Real-world results can differ when rates, timing, fees, definitions or measurement conditions differ.