🐎 Horsepower & Torque Calculator
Convert between horsepower and torque at any engine speed, enter two of the three and get the third, plus the metric kW and N·m equivalents.
Horsepower
285.6 hp
213 kW
Power in kW
213 kW
Horsepower = torque (lb-ft) × RPM ÷ 5252, the constant 5252 is where the torque and power curves always cross on a dyno. 1 hp = 0.7457 kW; 1 lb-ft = 1.356 N·m. 🔒 In your browser.
How the horsepower & torque calculator works
Power is torque times rotational speed, and in the traditional units that relationship is horsepower = torque (lb-ft) × RPM ÷ 5252. The constant 5252 comes from 33,000 ÷ 2π (one horsepower is 33,000 ft-lb per minute). Rearranged, torque = horsepower × 5252 ÷ RPM. The tool also converts to kilowatts and newton-metres. To see it in action: 400 lb-ft at 4,000 RPM is 400 × 4000 ÷ 5252 ≈ 305 hp; the same 400 lb-ft at 6,000 RPM makes 457 hp, because power keeps climbing with engine speed even when torque is flat. In metric units the equivalent relation is power (kW) = torque (N·m) × RPM ÷ 9549.
A consequence of the formula: horsepower and torque are always numerically equal at 5252 RPM, which is why dyno graphs of the two curves always cross at that point. Below 5252 RPM torque is the larger number; above it, horsepower is.
Frequently asked questions
How do I convert torque to horsepower?
Horsepower = torque (lb-ft) × RPM ÷ 5252. So 300 lb-ft at 5,000 RPM is 300 × 5000 ÷ 5252 ≈ 286 hp. The tool converts either direction and adds kW and N·m.
Why is the number 5252 used?
One horsepower is defined as 33,000 foot-pounds of work per minute. Converting rotational torque and RPM into that unit introduces a factor of 2π, and 33,000 ÷ 2π ≈ 5252, the constant in the horsepower formula.
Why do horsepower and torque cross at 5252 RPM?
Because horsepower = torque × RPM ÷ 5252. At exactly 5252 RPM the RPM ÷ 5252 term equals 1, so horsepower equals torque numerically, the two dyno curves always intersect there.
What is the difference between horsepower and torque?
Torque is the twisting force the engine makes; horsepower is the rate at which it does work, torque combined with how fast the engine spins. Torque gets you moving; horsepower (torque sustained at high RPM) determines top-end performance.
How do I convert horsepower to kilowatts?
Multiply by 0.7457-1 hp = 0.7457 kW. So 250 hp is about 186 kW. The tool shows the kW value automatically.
How do I convert torque in newton-metres to kilowatts?
Power (kW) = torque (N·m) × RPM ÷ 9549. The constant 9549 is 60,000 ÷ 2π, the metric counterpart of 5252. So 500 N·m at 3,000 RPM is 500 × 3000 ÷ 9549 ≈ 157 kW.
Can an engine make more torque than horsepower?
In the traditional lb-ft and hp units, yes, below 5,252 RPM the torque figure is numerically larger, and above it the horsepower figure is. They are two views of the same output, so comparing the raw numbers is a quirk of the units, not a physical contest.