Watts to Horsepower
The watt is the SI unit of power, equal to one joule per second, used to rate everything from light bulbs to engines. Mechanical horsepower, about 745.7 watts, is the traditional unit for rating car and engine power in the US and UK. 1 W equals ≈0.00134102 hp, so converting between them is a matter of multiplying by that fixed factor — type any value into the converter below and both sides update instantly as you type.
Both units belong to power, measured here against power's base unit (W) — every other power unit on this site converts through that same reference point, which is why the table below can also be read as a quick cross-check against nearby values.
Formula
hp = W × ≈0.00134102
W = hp × ≈745.7
Worked example: 5 W × ≈0.00134102 = ≈0.00670511 hp.
Conversion table
| Watt (W) | Horsepower (mech.) (hp) |
|---|---|
| 1 W | ≈0.00134102 hp |
| 2 W | ≈0.00268204 hp |
| 3 W | ≈0.00402307 hp |
| 5 W | ≈0.00670511 hp |
| 10 W | ≈0.0134102 hp |
| 20 W | ≈0.0268204 hp |
| 25 W | ≈0.0335256 hp |
| 50 W | ≈0.0670511 hp |
| 100 W | ≈0.134102 hp |
| 250 W | ≈0.335256 hp |
| 500 W | ≈0.670511 hp |
| 1,000 W | ≈1.34102 hp |
Frequently asked
- How many Horsepower in a watt?
- 1 W equals ≈0.00134102 hp.
- How do I convert Watts to Horsepower?
- Multiply the value in W by ≈0.00134102 to get hp. The converter above does this instantly as you type.
- Is the conversion exact?
- Yes — Watt and Horsepower (mech.) are both defined by a fixed conversion factor to power's base unit (W), so the result shown is exact to the precision displayed, not an approximation.