Power & Torque Conversions
Convert between different power and torque units.
Power and torque come in many units — horsepower, kilowatts, pound-feet, newton-metres, and amps — and converting between them correctly is essential whether you are reading an engine spec, sizing an electric motor, or comparing a US and a European figure. This hub collects every power and torque conversion calculator in one place.
Why Power Conversions Matter
An engine quoted at 200 hp, 149 kW, and 203 PS is the same engine described three ways. Mixing the units — or forgetting that metric horsepower (PS) is slightly smaller than mechanical horsepower — introduces errors of a few percent that matter when you are matching components or comparing vehicles. Torque has the same problem: pound-feet and newton-metres differ by a factor of 1.356, and confusing them throws off every downstream calculation.
The Key Conversion Constants
| Conversion | Multiply by |
|---|---|
| Horsepower → Kilowatts | 0.7457 |
| Kilowatts → Horsepower | 1.341 |
| Pound-feet → Newton-metres | 1.3558 |
| Newton-metres → Pound-feet | 0.7376 |
| Horsepower → Watts | 745.7 |
The cornerstone of engine power conversion is the 5252 rule, which links torque and horsepower: HP = (torque in lb-ft × RPM) ÷ 5252. Because both share this relationship, the HP to torque and torque to HP calculators are exact reverses of each other.
Which Conversion Tool Do You Need?
| If you want to… | Use this calculator |
|---|---|
| Find torque from a horsepower and RPM figure | HP to Torque |
| Find horsepower from torque and RPM | Torque to HP |
| Convert horsepower to kilowatts (or back) | HP to kW |
| Find motor current draw from horsepower | HP to Amps |
For a deeper explanation of how horsepower and torque relate, see our guide on horsepower vs torque and the 5252 rule.
Every calculator in this hub uses standard published formulas. Results are estimates whose accuracy depends on the values you enter.
Frequently Asked Questions
No, 1 kW is roughly 1.34 HP.
Horsepower to kilowatts and torque to horsepower are the most common. The 5252 rule links torque and horsepower, while 0.7457 converts HP to kW.
No. Metric horsepower (PS) is about 1.4% smaller than mechanical horsepower, so 100 PS equals roughly 98.6 mechanical HP.
Multiply newton-metres by 0.7376 to get pound-feet, or multiply pound-feet by 1.3558 to get newton-metres.
Because horsepower is defined as torque times RPM divided by 5252. At exactly 5252 RPM the two values are numerically equal on a same-scale dyno graph.