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Horsepower and torque calculator

Horsepower and torque are the same measurement viewed two ways, tied together by rpm. Enter either one and the rpm to get the other, in both US and metric units.

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Result

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Horsepower
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Torque
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Kilowatts
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Newton-meters
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Why 5,252?

Below 5,252 rpm an engine's torque number is always bigger than its horsepower number, and above it the horsepower is bigger. That's why every dyno chart's curves cross there.

How the conversion works

Horsepower = torque (lb-ft) × rpm ÷ 5,252
Torque (lb-ft) = horsepower × 5,252 ÷ rpm

One horsepower is 33,000 foot-pounds of work per minute. Converting a turning force (torque) into work per minute brings in 2π for each revolution, and 33,000 ÷ 2π is 5,252.

For metric units, 1 hp is 0.7457 kW and 1 lb-ft is 1.3558 Nm. The same relationship holds at every point on a dyno curve, so you can use this on any rpm you read off a chart.

Frequently asked questions

Why do horsepower and torque always cross at 5,252 rpm?

That crossing point is a mathematical consequence of the formula itself (horsepower = torque × rpm ÷ 5,252) — whenever torque and horsepower are plotted on the same graph, the two curves are mathematically guaranteed to intersect exactly at 5,252 rpm, every time, on every engine.

Which number matters more for how a car feels to drive?

Torque is generally what you feel as immediate acceleration and pulling power, especially at lower rpm, while horsepower (which factors in rpm) tends to track better with sustained high-speed performance — many enthusiasts consider torque the more "seat of the pants" number.

Why does the calculator give both US and metric units?

Horsepower and torque get reported differently depending on the source — American engines and parts commonly use hp and lb-ft, while many international specs use kW and Nm — having both avoids doing a separate unit conversion by hand.

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