Kilowatts and horsepower
A kilowatt is 1,000 watts. Car and motorcycle engine power in Europe, EV chargers, heat pumps and home solar systems use kW.
Mechanical horsepower is exactly 550 foot-pounds-force per second: about 745.7 watts. Car, boat and lawnmower engines in the US and UK, and electric motors, are rated in hp.
Worked example
Convert 150 kW: 150 × 1.34102209 = 201.1533134, so 150 kilowatts is 201.1533134 horsepower. Likewise 100 kW = 134.102209 hp.
Estimating in your head
Multiply by 1.3 for a quick figure; it is off by about 3.1%. For 150 kW that gives 195 hp, against 201.153 exactly.
Going the other way
To convert horsepower to kilowatts, divide by 1.34102209 (or multiply by 0.745699871582). The swap button between the boxes opens that page.
How this works
hp = kW × 1.34102209
1 kW = 1,000 W and 1 hp = ≈ 745.6998716 W, both by definition, so the factor is their ratio: 1.34102209 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many horsepower are in a kilowatt?
1 kilowatt = 1.34102209 horsepower. The factor is exact by definition but has endless decimals, so it is shown rounded; the page uses the full value.
How do I convert kilowatts to horsepower?
Multiply by 1.34102209. For example, 100 kW × 1.34102209 = 134.102209 hp.
What is 1,000 kW in horsepower?
1,000 kW = 1,341.02209 hp. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- NIST SP 811 Appendix B.9 — Factors for units listed by kind of quantity
- Wikipedia — Horsepower
Reviewed Oct 17, 2026 · test vectors fixtures/units/power/kw-to-hp/