Horsepower & Torque Calculator (HP ↔ Torque)

Horsepower and torque are linked by engine speed. Enter the torque in lb-ft and the RPM to get the horsepower at that point — and the kilowatt equivalent.

How this calculator works

The formula is HP = torque × RPM ÷ 5,252. Torque is twisting force; horsepower is how fast that force does work, which is why power depends on engine speed. To go the other way, torque = HP × 5,252 ÷ RPM. The 5,252 constant is where the horsepower and torque curves always cross on a dyno chart.

What changes the number

Peak horsepower and peak torque happen at different RPMs — this gives the HP at the RPM you enter.
One metric horsepower differs slightly from one mechanical (SAE) hp; we use the standard 5,252 SAE relationship and 0.7457 kW per hp.
Wheel horsepower (measured at the wheels) is lower than crank horsepower due to drivetrain losses.

Frequently asked questions

Why 5,252?

It comes from the definition of horsepower (33,000 ft-lb per minute) divided by 2π. It’s the RPM at which horsepower and torque are always numerically equal on a dyno graph.

How do I convert HP to torque?

Rearrange the formula: torque (lb-ft) = HP × 5,252 ÷ RPM. So 300 hp at 5,000 rpm is about 315 lb-ft.

Is more torque or more horsepower better?

Torque is the shove you feel; horsepower determines top-end and how that shove holds at speed. They’re two views of the same engine output at different RPMs.