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Horsepower Calculator
Convert torque and engine speed into mechanical or metric horsepower, watts and kilowatts. You can also solve for torque or RPM when you know the other two values.
How do you calculate horsepower from torque and RPM?
Mechanical power is torque × angular speed. With torque in newton-metres and speed in RPM, power in watts is torque × 2π × RPM ÷ 60. For example, 100 N·m at 1,000 RPM is about 10.47 kW or 14.24 metric horsepower. This ideal shaft-power calculation does not include drivetrain losses.
Frequently asked questions
How do you calculate horsepower from torque and RPM?
Mechanical power is torque × angular speed. With torque in newton-metres and speed in RPM, power in watts is torque × 2π × RPM ÷ 60. For example, 100 N·m at 1,000 RPM is about 10.47 kW or 14.24 metric horsepower. This ideal shaft-power calculation does not include drivetrain losses.
Are my values uploaded?
No. The calculation runs in this browser; values are not uploaded or saved.
What is the difference between horsepower and metric horsepower?
Mechanical horsepower (hp) is 745.699871582 watts. Metric horsepower (PS) is 735.49875 watts. They are close, but not identical.
Why do torque and RPM determine engine power?
Power is the rate of rotational work. At a given torque, a shaft turning faster transfers more energy each second. The formula assumes steady rotation and ideal shaft measurements.
Does this show horsepower at the wheels?
No. It calculates ideal power at the shaft from the torque and RPM you enter. Wheel power is usually lower because the drivetrain loses energy, and measurement methods differ.