The exact equivalent
One kilowatt is 1.34102 mechanical horsepower. A mechanical horsepower is 745.7 watts, defined as 550 foot-pounds per second.
1 kW = 1.34102209 HP
1 HP = 0.74569987 kW
How to convert it by hand
Just multiply by the conversion factor. To go from kilowatts to mechanical horsepower, multiply by 1.341022; to come back, divide by that same number or multiply by 0.7457.
For example: 25 kW × 1.341022 = 33.5256 HP.
A tip that saves mistakes: check the result goes the way you expect. If mechanical horsepower are a smaller unit than kilowatts, the number has to come out bigger. If it comes out smaller, you divided when you should have multiplied.
Conversion table
| kW | HP |
|---|---|
| 1 | 1.341 |
| 2 | 2.682 |
| 5 | 6.7051 |
| 10 | 13.4102 |
| 20 | 26.8204 |
| 50 | 67.0511 |
| 100 | 134.1022 |
Reference points to picture it
| Reference | Equals |
|---|---|
| 1 kW | 1.341 hp |
| A domestic boiler | 24 kW = 32.2 hp |
| A family car | 110 kW = 147.5 hp |
| 1 hp | 0.746 kW |
The trick for doing it in your head
Multiply by 4 and divide by 3. For 75 kW: 300 ÷ 3 = 100 hp, against a true 100.6.
It is fine for getting by without a phone, but not for anything that depends on precision: in a recipe, on a building site or in a dose, use the exact conversion.