Formula
HP = P (W) ÷ 746
This uses electric (mechanical/imperial) horsepower. Metric horsepower (PS) uses 735.5 W instead.
Worked example
A 1,000 W motor: HP = 1000 ÷ 746 = 1.34 HP.
Reference table
Quick reference
| Watts | Horsepower |
|---|---|
| 250 | 0.34 |
| 500 | 0.67 |
| 746 | 1 |
| 1,000 | 1.34 |
| 2,000 | 2.68 |
| 5,000 | 6.7 |
Where this shows up in the real world
Comparing an electric motor to the gas engine it replaces, or decoding why a '746 W' label and a '1 HP' label describe the same machine — this conversion is the translation layer. It shows up everywhere from pool-pump shopping in Florida to converting treadmill specs to something a buyer can feel.
Common mistakes to avoid
Watch which horsepower you're using: electric/imperial HP is 746 W, but metric horsepower (PS, common in European vehicle specs) is 735.5 W — a 1.4% gap that matters in contracts and spec sheets. And remember the conversion describes output; an appliance's electrical consumption is higher than its mechanical HP suggests.
Frequently asked questions
Which horsepower does this use?
Electric/imperial horsepower: 1 HP = 746 W. Metric horsepower (PS, common in car specs) is 735.5 W — about 1.4% smaller.
Is a '1 HP' water pump really 746 W?
Its rated mechanical output is. Electrical input is higher due to motor losses — often 900–1,100 W input for a 1 HP pump.
Why does horsepower still exist?
Tradition and industry convention — motors, pumps and compressors are still sold by HP in many markets, including Pakistan and the US.