Formula
P (W) = HP × 746
For metric horsepower (PS), multiply by 735.5 instead.
Worked example
A 2 HP motor: P = 2 × 746 = 1,492 W ≈ 1.5 kW of mechanical output.
Reference table
Quick reference
| HP | Watts |
|---|---|
| 0.25 | 186.5 |
| 0.5 | 373 |
| 1 | 746 |
| 2 | 1,492 |
| 5 | 3,730 |
| 10 | 7,460 |
Where this shows up in the real world
Going from a motor rating to electrical planning: a 2 HP pool pump outputs ~1.5 kW mechanically, which means roughly 1.8–2 kW of electrical input once efficiency is paid — the number that matters for the generator list, the solar inverter, or the monthly bill at 8 hours of summer runtime.
Common mistakes to avoid
The standard mistake is treating HP × 746 as the consumption figure. It's the output floor; divide by efficiency (0.85–0.92 for decent motors) for actual input watts. Older or cheap motors run worse. If the difference between 1,492 W and 1,750 W matters to your design, measure rather than assume.
Frequently asked questions
Does a 1 HP appliance consume 746 W of electricity?
It outputs 746 W mechanically. Electrical consumption is higher because no motor is 100% efficient — expect roughly 850–1,100 W input.
How do I get from HP to kW?
Multiply HP by 0.746. A 10 HP motor outputs about 7.46 kW.
Why 746 specifically?
James Watt defined 1 HP as 550 foot-pounds per second, which converts to 745.7 W — rounded to 746 in electrical practice.