About the HP to kW
This HP to kW converter turns horsepower into kilowatts for every common definition of horsepower: mechanical (imperial) horsepower used for US and UK engine ratings, metric horsepower (PS, CV or pk) used across Europe and Asia, electrical horsepower used on motor nameplates, and boiler horsepower used for steam plants. Choose the type, enter the number and read kW, watts, BTU per hour and the equivalent in the other horsepower type.
Car buyers use it to compare an EU spec sheet listing kW or PS with a US brochure quoting hp, electricians use it to size breakers and drives for pump and compressor motors, and boat, generator and EV owners use it to compare engine outputs with electric motors rated in kW.
Mechanical horsepower is 550 foot-pounds per second, or 745.7 W. Metric horsepower is 75 kilogram-force meters per second, or 735.5 W — about 1.4% smaller — so a car rated at 150 PS makes 148 hp. Electrical horsepower is set at exactly 746 W.
With the default inputs, the kilowatts is 111.855 kW. Change any value above to recalculate instantly.
How to use the hp to kw
- 1Enter the horsepower figure.
- 2Choose the horsepower type — mechanical for US/UK cars, metric (PS) for European specs, electrical for motors.
- 3Read the result in kilowatts, plus watts and BTU/h.
- 4Use the equivalents to compare hp and PS ratings directly.
Formula and method
Horsepower is converted to watts by multiplying by the wattage of the chosen horsepower type, then divided by 1,000 for kilowatts. Mechanical horsepower is 550 ft·lbf/s = 745.699872 W; metric horsepower is 75 kgf·m/s = 735.49875 W; electrical horsepower is defined as 746 W; boiler horsepower is about 9,809.5 W.
The equivalents in the other horsepower type divide the same wattage by that type’s watts. BTU per hour multiplies watts by 3.412142, the heat-flow equivalent used in HVAC.
- hp
- Mechanical horsepower = 745.7 W
- PS
- Pferdestärke (metric hp) = 735.5 W
- kW
- Kilowatt = 1,000 W
Worked examples
150 hp car engine
150 × 745.7 W = 111,855 W, or 111.9 kW. The same engine would be quoted as 152 PS in Europe because the metric horsepower is slightly smaller.
100 PS European hatchback
100 PS × 735.5 W = 73,550 W = 73.55 kW, which is about 98.6 mechanical hp. EU registration documents show the 74 kW figure.
10 hp electric motor
Electrical horsepower is exactly 746 W, so a 10 hp motor delivers 7.46 kW of output — virtually identical to 10 mechanical hp.
Frequently asked questions
How do I convert hp to kW?+
Multiply mechanical horsepower by 0.7457. For example, 200 hp × 0.7457 = 149.1 kW. For metric horsepower (PS) multiply by 0.7355 instead.
Is bhp the same as hp?+
Brake horsepower (bhp) is the engine output measured at the crankshaft, using the mechanical horsepower unit of 745.7 W. "hp" on a spec sheet usually means the same unit, though wheel horsepower is lower because of drivetrain losses.
What is the difference between hp and PS?+
PS (metric horsepower) is 735.5 W while mechanical hp is 745.7 W, so 1 PS = 0.986 hp. A car rated 200 PS produces about 197 hp.
How many kW is 1 horsepower?+
One mechanical horsepower equals 0.7457 kW, one metric horsepower 0.7355 kW, and one electrical horsepower exactly 0.746 kW.
Why do EVs and European cars quote kW?+
The kilowatt is the SI unit of power, and EU regulations require engine output in kW on type-approval and registration documents. Electric motors are naturally rated in kW, so EV makers use it too.