HP to kW converter, horsepower to kilowatts.

To convert hp to kW, multiply the horsepower by 0.7457. One mechanical horsepower is 0.745699872 kW, so 10 hp is 7.457 kW and 200 hp is 149.14 kW. If the figure is metric horsepower (PS), use 0.73549875 instead: 200 PS is 147.1 kW. For electric horsepower the factor is a round 0.746.

How to use the converter

1. Type the rating in the Mechanical horsepower (hp) box. A 5 hp engine on a small machine gives 3.728 kW.
2. The cards under the big result show the same power in Metric horsepower, Electric horsepower and Watts. They convert your hp figure into those units, so they only matter if you want to compare.
3. If your number is already in PS or electric hp, go to the KW to HP converter, type the kilowatts there and read the metric and electric cards.
4. Set Decimals and use Copy result or Copy link. The table under the tool has fractions of a horsepower for appliance motors.

Where horsepower ratings turn up

Small engines, pressure washers, boat outboards, pumps, garbage disposals and garage door openers are often sold by horsepower in the United States, while a lot of the rest of the world rates the same machines in kilowatts. A half horsepower motor is 0.3728 kW. A 1 hp motor is 0.7457 kW. A 5 hp engine is 3.728 kW. You need the kilowatt figure to compare, to size a generator, or to fill a form that asks for kW.

A motor's hp is shaft power, not what it draws

The horsepower on a motor nameplate is how much mechanical power it delivers at the shaft. The electricity it takes from the wall is higher, because some energy is lost as heat. A 5 hp motor delivers 3.728 kW at the shaft and draws more than that. This page converts units only. It does not know your motor's efficiency, so do not read the result as the electrical load.

The exact numbers

NIST Special Publication 811, Appendix B.8 (checked 26 Oct 2026) marks electric horsepower as exactly 746 W and prints mechanical horsepower (550 ft·lbf/s) as 745.6999 W and metric horsepower as 735.4988 W, rounded. The converter uses the full values that follow from the definitions: 745.69987158227022 W for mechanical horsepower and 735.49875 W for metric horsepower, which is 75 kilogram-force meters per second at standard gravity.

Worked examples

• A 300 hp truck engine. 300 × 0.745700 = 223.71 kW.
• A 150 hp outboard. 111.85 kW.
• A 20 hp pump motor. 14.91 kW.
• A 1/2 hp garbage disposal. 0.3728 kW, which is 372.8 W.
• A 200 PS European car. 147.1 kW, which is 197.26 hp in mechanical horsepower.

Quick mental check

Take three quarters of the horsepower to get a close kilowatt figure. 100 hp times 0.75 is 75 kW, against the exact 74.57. The error is 0.57 percent. For a better result use 0.7457, which is within 0.00002 percent.

From horsepower to energy

Kilowatts measure power, how fast energy is used. A 3.73 kW load running for one hour uses about 3.73 kilowatt-hours. The converter stops at power. To go from hp to a running cost you also need hours and a price per kWh.

Related pages: KW to HP for the reverse, the watts to amps calculator, and the unit converter for anything else.