Engineering
Horsepower to kW Converter Calculator
Power ratings for engines and motors appear in horsepower (hp) in the US and many product specs, and in kilowatts (kW) in SI-metric countries. This calculator handles the three main horsepower definitions — mechanical (most common), metric (PS/CV), and electric — so you can convert accurately regardless of the source.
Calculator
Formula
Formula
kW = hp × W_per_hp ÷ 1000 hp = kW × 1000 ÷ W_per_hp
Mechanical hp: 1 hp = 745.69987 W = 0.74570 kW. Metric hp (PS): 1 PS = 735.49875 W = 0.73550 kW. Electric hp: 1 hp(E) = 746 W = 0.746 kW exactly. To convert kW to any hp type, divide by the corresponding watt value.
Worked example
A European car is rated at 200 PS (metric hp). Convert to kW and mechanical hp.
- 1.200 PS × 735.499 W/PS = 147,100 W = 147.1 kW
- 2.To mechanical hp: 147,100 W / 745.700 W/hp = 197.3 hp
200 PS = 147.1 kW = 197.3 mechanical hp.
Assumptions and limitations
- Mechanical hp (SAE): 550 ft·lbf/s = 745.69987 W. Standard for US automotive ratings.
- Metric hp (PS, CV, PK, hk): 75 kgf·m/s = 735.49875 W. Used in Europe, Japan.
- Electric hp: 746 W exactly. Used for electric motor nameplate ratings in the US.
- Boiler hp (9,810 W) is not included — it is only used for steam boiler output.