maratoolHow to convert HP to kW (and why metric HP differs)
Type a power value — read hp, PS, kW, watts, BTU/h, or tons of refrigeration instantly.
Car engines are quoted in hp or PS, motors in kW, and HVAC in BTU/h or tons. The Power Converter converts all of them through the SI watt, keeping mechanical and metric horsepower separate.
How it works
- Pick units — "Horsepower, mechanical (hp)" to "Kilowatt (kW)", or any other pair.
- Type a value — the result updates as you type, with swap and copy.
- Copy — one click, with "Copied!" feedback.
Power conversion factors
Every unit converts through the watt (the base unit). To convert A → B, multiply by A's factor and divide by B's:
| Unit | = this many watts |
|---|---|
| Watt (W) | 1 |
| Kilowatt (kW) | 1,000 |
| Megawatt (MW) | 1,000,000 |
| Horsepower, mechanical (hp) | 745.69987158227 |
| Horsepower, metric (PS) | 735.49875 |
| BTU per hour (BTU/h) | 0.293071070172 |
| Foot-pound per second (ft·lbf/s) | 1.355817948331 |
| Ton of refrigeration (RT) | 3,516.852842066667 |
When you need it
A 150 hp engine is 111.9 kW or 152.1 PS — the PS number is always slightly bigger, which is why European brochures prefer it. For HVAC sizing, 1 kW of cooling is about 3,412 BTU/h.
Sources & methodology
Conversion factors follow NIST Special Publication 811; exact-by-definition factors are marked in the tool itself. All math runs client-side in your browser — nothing is uploaded.
More conversion guides
- How to convert calories, joules, kWh, and BTU
- How to convert Nm to ft-lb for torque specs
- How to convert square feet to square meters (and any area unit)
Or browse everything at once in the new unit & sizing converters roundup.