How to use
- Enter a value, then pick the unit you are converting from and the unit you want to.
- The result appears instantly, and the table below shows the same power in every unit.
- When you pick horsepower or a heating unit, a short note explains which definition is used.
Conversion factors
Power is energy per unit of time. One watt is one joule per second.
| Unit | In watts | Notes |
|---|---|---|
| 1 kW | 1,000 W | |
| 1 hp (mechanical) | ≈ 745.69987 W | 550 ft·lbf/s, used in the US and UK |
| 1 PS (metric horsepower) | 735.49875 W | 75 kgf·m/s, common in European and Asian car specs |
| 1 BTU/h | ≈ 0.29307 W | International Table BTU per hour |
| 1 kcal/h | 1.163 W | International Table calorie, an HVAC convention |
Examples
- A 300 hp engine produces about 223.7 kW.
- A 150 kW electric motor is about 201 hp or 204 PS.
- A 12,000 BTU/h air conditioner (one “ton” of cooling) moves about 3.52 kW of heat.
- A 1,500 W space heater puts out about 5,118 BTU/h.
Things to keep in mind
- hp and PS differ by about 1.4%. The same engine shows a slightly bigger number in PS. Brake horsepower (bhp) is mechanical horsepower measured at the crankshaft.
- An air conditioner’s BTU/h rating is its cooling capacity — the heat it moves — not the electricity it draws, which is much lower.
- kW is a rate; kWh is an amount of energy. Convert energy with the energy converter, or try the unit converter for other unit types.
FAQ
How many kW is one horsepower?
About 0.7457 kW for mechanical horsepower and 0.7355 kW for metric horsepower (PS).
How many BTU/h is one kW?
About 3,412 BTU/h.
How many watts is a ton of refrigeration?
A refrigeration ton is defined as 12,000 BTU/h, which is about 3,517 W. Enter 12000 BTU/h above to see it in every unit.