Torque to Horsepower
Calculator
Convert torque at a selected engine RPM into mechanical horsepower and kilowatts using power equals torque times angular speed.
Your setup
Your results
CalculatedTorque is a moment; power is a rate of work. Equal numeric values at about 5,252 rpm apply only to lbf·ft and mechanical hp.
Does not estimate a torque curve or establish dyno measurement accuracy.
How the calculation works
Follow the formula and keep the input units consistent at every step.
P(kW) = torque(Nm) × RPM × 2π / 60000; HP = kW / 0.7456998716- Use torque and RPM measured at the same operating point.
- Convert RPM to radians per second.
- Multiply torque by angular speed and convert watts to kW or mechanical hp.
A Worked Example
400 lbf·ft at approximately 5,252.11 rpm gives 400 mechanical hp. At the same torque and twice the RPM, power doubles.
What Your Result Means
Torque is a moment; power is a rate of work. Equal numeric values at about 5,252 rpm apply only to lbf·ft and mechanical hp.
Assumptions & Limitations
Does not estimate a torque curve or establish dyno measurement accuracy.
Common Mistakes
Peak torque and peak power usually occur at different RPM; do not combine unrelated peaks.
Questions about this calculation
Which values should I enter?
Use torque and RPM measured at the same operating point. Peak torque and peak power usually occur at different RPM; do not combine unrelated peaks.
How should I interpret the result’s precision?
Displayed results are rounded for readability. Intermediate calculations retain floating-point precision; extra displayed decimals do not improve your input accuracy.
Can I use metric units?
Yes. Select Metric above the calculator to convert your inputs. Results always state their units. Tire-size designations keep their conventional mm and inch units.
What are the main limitations?
Does not estimate a torque curve or establish dyno measurement accuracy.
Method, sources & relevant guides
Power and rate of work; mechanical horsepower conversion follows 550 ft·lbf/s.
NASA Glenn — What is power?Method documentation updated October 18, 2026. Independent professional review has not been claimed. Read the calculation and review policy.