HP to KW Converter
Convert horsepower to kilowatts — multiply by 0.7457. Results update as you type; exact factors shown.
One horsepower (mechanical) is 0.7457 kilowatts — see the exact factor, not a rounded rule of thumb.
How the hp to kw converter works
Power converts through the watt. Mechanical horsepower is 550 ft·lbf/s = 745.6999 W; metric horsepower (PS, used in European car specs) is 735.4988 W. Air-conditioner capacities are quoted in kW, BTU/h (1 W = 3.412 BTU/h) or tons of refrigeration (3.517 kW).
The US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
Common power conversions
| From | To | Units |
|---|---|---|
| 1 hp | 0.7457 kW | horsepower (mechanical) to kilowatts |
| 5 hp | 3.7285 kW | horsepower (mechanical) to kilowatts |
| 10 hp | 7.457 kW | horsepower (mechanical) to kilowatts |
| 25 hp | 18.6425 kW | horsepower (mechanical) to kilowatts |
| 50 hp | 37.285 kW | horsepower (mechanical) to kilowatts |
| 100 hp | 74.57 kW | horsepower (mechanical) to kilowatts |
| 150 hp | 111.855 kW | horsepower (mechanical) to kilowatts |
| 200 hp | 149.14 kW | horsepower (mechanical) to kilowatts |
| 300 hp | 223.71 kW | horsepower (mechanical) to kilowatts |
| 400 hp | 298.2799 kW | horsepower (mechanical) to kilowatts |
| 500 hp | 372.8499 kW | horsepower (mechanical) to kilowatts |
| 750 hp | 559.2749 kW | horsepower (mechanical) to kilowatts |
Units in this converter and their exact factors
| Unit | Symbol | One unit in watts |
|---|---|---|
| watt | W | 1 watt |
| kilowatt | kW | 1,000 watt |
| megawatt | MW | 1,000,000 watt |
| horsepower (mechanical) | hp | 745.6998715823 watt |
| metric horsepower (PS) | PS | 735.49875 watt |
| BTU per hour | BTU/h | 0.29307107 watt |
| ton of refrigeration | TR | 3,516.8528421 watt |
FAQFrequently asked questions about power conversion
How many kW is 1 hp?
0.745700 kW.
What is 300 hp in kW?
223.7 kW.
Why do European cars quote kW?
Because it is the SI unit and what registration documents record; PS and hp are marketing figures.
Is an electric motor rated the same way?
Its output is, but electric motors deliver peak torque immediately, so the same rating feels quicker.
What about heating and cooling?
Those are also watts — a 3 kW heater is about 4 hp of heat, though nobody puts it that way.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.