Watts to Horsepower Converter
Convert watts to mechanical horsepower — divide by 745.7. Results update as you type; exact factors shown.
One watt is 0.0013 horsepower (mechanical) — see the exact factor, not a rounded rule of thumb.
How the watts to horsepower 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 UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common power conversions
| From | To | Units |
|---|---|---|
| 100 W | 0.1341 hp | watts to horsepower (mechanical) |
| 500 W | 0.6705 hp | watts to horsepower (mechanical) |
| 745.7 W | 1 hp | watts to horsepower (mechanical) |
| 1,000 W | 1.341 hp | watts to horsepower (mechanical) |
| 5,000 W | 6.7051 hp | watts to horsepower (mechanical) |
| 10,000 W | 13.4102 hp | watts to horsepower (mechanical) |
| 50,000 W | 67.0511 hp | watts to horsepower (mechanical) |
| 74,570 W | 100 hp | watts to horsepower (mechanical) |
| 100,000 W | 134.1022 hp | watts to horsepower (mechanical) |
| 150,000 W | 201.1533 hp | watts to horsepower (mechanical) |
| 200,000 W | 268.2044 hp | watts to horsepower (mechanical) |
| 500,000 W | 670.511 hp | watts to horsepower (mechanical) |
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 horsepower is 1 kW?
1.341 hp.
What is 100 kW?
134 hp.
Which horsepower does a car use?
US and UK specs use mechanical hp; continental Europe uses PS, which reads about 1.4% higher for the same engine.
What is a person's sustained output?
About 100 W, or 0.13 hp. A trained cyclist holds 300 to 400 W for an hour.
What is 745.7 W?
Exactly one horsepower.
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 Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.