HP to kW Converter
Convert a US automotive or generator rating written in mechanical horsepower into kilowatts for a metric data sheet or EV comparison.
Updated
How to use
- Enter mechanical (imperial) horsepower from the brochure or dyno sheet.
- Read kilowatts. 100 hp is 74.5700 kW; 1 hp is 0.7457 kW.
- If the badge says PS, DIN hp or cv, that unit is about 1.4% smaller than this hp.
- Generator “kW” on a standby label may already be electrical output — do not double-convert.
How it works
US car ads, lawn equipment and many generator stickers still quote horsepower. Grid equipment, EV lists and IEC motor plates quote kilowatts. Mechanical horsepower is 550 ft·lbf/s = 745.6998715822702 W, so this page multiplies hp by 0.7456998715822702. 200 hp is 149.1400 kW. 300 hp is 223.70996 kW, shown as 223.7100 kW at four decimals.
Brake horsepower (bhp) in older British usage is the same mechanical idea measured at the crank. Wheel horsepower after a drivetrain is a smaller number; converting bhp to kW does not invent wheel kW.
Metric PS is 735.49875 W. A “100 PS” engine is 73.55 kW, not 74.57 kW. If you put 100 into this converter you are claiming mechanical hp. Read the badge letters before you compare two cars.
Standby generators are often sold as “10,000 watt” or “10 kW” and separately as horsepower of the engine. Engine hp is not the same as electrical kW after generator efficiency. Convert the figure that is actually labelled hp; do not assume 10 kW electrical equals 13.4 hp of engine after losses unless the manufacturer says so.
Boiler horsepower is a steam rating and is far larger. It is not this page.
Formula
kW = hp × 0.7456998715822702
Worked examples
100 mechanical hp
100 hp → 74.5700 kW
One horsepower
1 hp → 0.7457 kW
A 200 hp engine rating
200 hp → 149.1400 kW
hp to kW (mechanical)
| hp (mechanical) | kW |
|---|---|
| 1 | 0.7457 |
| 100 | 74.57 |
| 150 | 111.855 |
| 200 | 149.14 |
| 250 | 186.425 |
| 300 | 223.71 |
Useful notes
- Standard: mechanical (imperial) horsepower, 550 ft·lbf/s.
- Not metric horsepower (PS) and not boiler horsepower.
- Electrical output of a generator includes efficiency the engine hp does not.
FAQ
- How many kilowatts is 1 horsepower?
About 0.7457 kW for mechanical horsepower (exactly 745.6998716 W).
- Is this the same as metric HP?
No. Metric PS is 735.49875 W. A “100 PS” engine is about 73.55 kW, not 74.57 kW.
- Do EV motors use horsepower?
They are usually quoted in kW. Convert kW to hp on the inverse page if you want a horsepower reading.
- How many kW is 400 hp?
400 × 0.7456998716 ≈ 298.2799 kW.
- Why is 746 W sometimes used?
Some texts round mechanical horsepower to 746 W. This page uses the 550 ft·lbf/s definition (745.6998716 W).
Related tools
See all Conversions tools.