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Horsepower and Torque Calculator

Convert between horsepower, kilowatts and torque at a given engine speed.

Result

Enter your values and select Calculate to see the result.

Runs in your browser — nothing you enter is sent to a server.

How the Horsepower and Torque Calculator works

Power is torque times rotational speed. Choose what to find — power, torque or engine speed — and enter the other two, in hp or kW and N·m or lb·ft. The result shows power in horsepower, kilowatts and metric horsepower (PS), and torque in both units.

Formulas

Metric

kW = N·m × rpm ÷ 9,549

Imperial

hp = lb·ft × rpm ÷ 5,252

That's why hp and lb·ft curves cross at 5,252 rpm. 1 hp = 745.7 W; 1 PS = 735.5 W.

Examples

400 N·m at 5,000 rpm

= 209.4 kW, 280.9 hp (295 lb·ft).

100 kW at 6,000 rpm

Needs about 159 N·m of torque.

Frequently asked questions

hp or PS?

European figures often use PS (metric horsepower), which is about 1.4% smaller than mechanical hp.

Why do engines quote peak figures at different rpm?

Torque usually peaks lower in the rev range than power; each is quoted at its own peak.

Wheel or engine power?

These are engine figures; power at the wheels is lower because of drivetrain losses.

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