Engine torque calculator

Find shaft torque from power and rotational speed: torque = watts ÷ angular speed.

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Shaft power (kW)

Shaft speed (rpm)

Answer

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Find shaft torque from power and rotational speed: torque = watts ÷ angular speed.

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Precision and calculation record

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Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

Step-by-step calculation

Inputs are substituted below. Each line evaluates the next operation; intermediate values are displayed to 12 significant digits while the calculation uses full precision.

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Formula and assumptions

Power and speed must describe the same shaft at the same operating point. Zero rpm cannot determine torque from power. No drivetrain loss or maximum load is assumed.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using Engine torque calculator

Find shaft torque from power and rotational speed: torque = watts ÷ angular speed.

Power and speed must describe the same shaft at the same operating point. Zero rpm cannot determine torque from power. No drivetrain loss or maximum load is assumed.

Next: Engine horsepower calculator

Next: Engine rpm calculator

A worked example

Example inputs: shaft power (kw) = 10, shaft speed (rpm) = 3000. Torque (N·m) = 31.8309886184.

Before you use the result

Power and speed must describe the same shaft at the same operating point. Zero rpm cannot determine torque from power. No drivetrain loss or maximum load is assumed.

Example results for shaft power (kw)

These examples use Shaft speed (rpm): 3000. They are reference calculations, not recommended settings.

Shaft power (kW)	Torque (N·m)
5	15.9154943092
10	31.8309886184
20	63.6619772368

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