Home/Tools/Energy, power & force
Horsepower to Kilowatts Converter
1 hp = 0.7457 kW. Switch below for metric horsepower (PS).
—
Three quarters of a kilowatt, roughly
One mechanical horsepower is 745.7 watts, so dividing by about three quarters gets you close. A 200 hp car is about 149 kW.
1 hp = 0.7456999 kW 1 PS = 0.7354988 kW
James Watt worked the figure out in the 1780s to sell steam engines to mine owners who measured everything in horses. He settled on 33,000 foot-pounds per minute, which in SI comes to 745.7 watts.
But there are two horsepowers. European car literature uses the metric horsepower, PS or CV, which is 735.5 W — about 1.4 % smaller. A car quoted at 200 PS is 197 hp. The switch under the boxes picks between them.
Horsepower
James Watt devised it in the 1780s to sell steam engines to mine owners who thought in horses. He settled on 33,000 foot-pounds per minute, which works out at 745.7 watts.
There is more than one horsepower. The mechanical or imperial horsepower is 745.7 W. The metric horsepower, written PS or CV and common in European car specifications, is 735.5 W — about 1.4 % smaller. A car quoted at 200 PS is 197 hp.
The kilowatt
A thousand watts, and the practical size for appliances, motors and vehicle engines outside the United States. A family car makes 75–150 kW.
Do not confuse it with the kilowatt-hour on an electricity bill. A kilowatt is a rate; a kilowatt-hour is an amount of energy — one kilowatt sustained for an hour, which is 3.6 megajoules.
The working, step by step
Every line updates with whatever you type above. The point is the method, which is the same for any pair of units in this family.
The same quantity, two different numbers
One physical amount, read off two scales. The tick marks do not line up, and the gap between them is the conversion factor made visible.
How much is that?
A number is easier to judge next to something familiar.
Your turn
Reading a method and being able to use it are different things. Answer within half a per cent and it counts as correct.
Score: 0 of 0
How to use this converter
- Type into either box. The other side updates as you go; there is no button to press.
- Swap the direction with the button between the boxes, carrying your value across.
- Set the decimals if the default is more or less precision than you need.
- Copy the answer with its unit, ready to paste.
- Use the shortcut buttons for the values that come up most often.
- Share the result. The address bar tracks what you type, so the link you copy opens on the same number.
Common uses and tips
Where this comes up
- Car specifications. European figures come in kW or PS, American ones in hp. The same engine gets three different numbers.
- Appliances and tools, rated in watts almost everywhere.
- Generators, motors and pumps, where catalogues mix kW and hp freely.
- Energy generation, where megawatts describe capacity.
The trap: which horsepower?
There are two in common use, and they differ by about 1.4 %.
- Mechanical (imperial) horsepower — 745.7 W. Watt's original figure, used in Britain and America.
- Metric horsepower, written PS or CV — 735.5 W. Standard in European car literature.
A car advertised at 200 PS is 197 hp. On these pages the switch under the boxes picks between the two.
Tips worth knowing
- Power is a rate. A 2 kW heater uses 2 kilowatt-hours of energy in an hour.
- Roughly, 1 kW is 1.34 hp and 1 hp is about three quarters of a kilowatt.
- Peak and continuous ratings differ. A motor's advertised figure is often peak, not what it will sustain.
Values people look up most
Each one opens the converter with the number already in it.
- 1 hp to kW
- 5 hp to kW
- 10 hp to kW
- 20 hp to kW
- 50 hp to kW
- 75 hp to kW
- 100 hp to kW
- 120 hp to kW
- 150 hp to kW
- 180 hp to kW
- 200 hp to kW
- 250 hp to kW
- 300 hp to kW
- 350 hp to kW
- 400 hp to kW
- 500 hp to kW
- 600 hp to kW
- 700 hp to kW
- 1,000 hp to kW
Quick reference
Using mechanical horsepower of 745.7 W.
| Horsepower | Kilowatts |
|---|---|
| 1 hp | 0.7457 kW |
| 10 hp | 7.456999 kW |
| 50 hp | 37.284994 kW |
| 100 hp | 74.569987 kW |
| 150 hp | 111.854981 kW |
| 200 hp | 149.139974 kW |
| 300 hp | 223.709961 kW |
| 500 hp | 372.849936 kW |
| 1,000 hp | 745.699872 kW |
Questions people ask
How many kW in 1 hp?
0.7457 kW for mechanical horsepower, or 0.7355 kW for metric horsepower (PS).
What is the difference between hp and PS?
About 1.4 %. Mechanical hp is 745.7 W; metric PS is 735.5 W. European car makers quote PS.
What is 200 hp in kW?
149.14 kW.
Why 745.7 watts?
James Watt defined horsepower as 33,000 foot-pounds per minute, which converts to 745.7 W.