Power converters
Convert engine and motor power between kilowatts and horsepower.
About power conversion
Power is the rate of doing work. The SI unit is the watt, and engines, motors and heaters are rated in kilowatts in most of the world. Horsepower, invented by James Watt to compare steam engines with horses, survives in the car industry and in the United States. There are several horsepowers: the mechanical (imperial) horsepower of 745.7 W, the metric horsepower (PS, CV, ch) of 735.5 W, and the electrical horsepower of 746 W. The converters here use the mechanical horsepower.
Conversion factors at a glance
| Unit | Equals |
|---|---|
| 1 kW | 1.341 hp = 1.360 PS |
| 1 hp (mechanical) | 0.7457 kW = 1.014 PS |
| 1 PS (metric hp) | 0.7355 kW = 0.986 hp |
| 1 MW | 1 000 kW = 1 341 hp |
Which converter do I need?
Cars and motorcycles. Kilowatts to horsepower for European and Australian spec sheets, horsepower to kilowatts for registration, insurance and tax bands. Electric vehicles. Motor output is always given in kW; multiply by 1.34 for the familiar horsepower figure. Motors, pumps and tools. Industrial nameplates carry both, but catalogues from different countries do not.
Power versus energy
Kilowatts describe how fast energy flows; kilowatt-hours describe how much energy was used. A 100 hp engine at full throttle for an hour consumes 74.6 kWh of fuel energy. Electricity bills, batteries and EV charging sessions are in kWh — a different quantity from the kW rating of the motor.
Common questions
How many horsepower is 100 kW? 134 hp (136 PS). How many kW is 200 hp? 149 kW. Is PS the same as hp? Nearly: 1 PS is 0.986 hp. What is the difference between kW and kWh? kW is power, kWh is energy — power multiplied by time. How much power does a typical car have? 75–150 kW, 100–200 hp.