Driver tools Power converter: bhp, PS and kW Apr 2012
- Convert quickly and easily between bhp, kW and PS
- Learn about the different measures of engine power
- See the difference between torque and brake horsepower
- Find out how to check your car's engine power
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| Power converter | ||
|---|---|---|
| BHP | PS | kW |
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 3 | 2 |
| 4 | 4 | 3 |
| 5 | 5 | 4 |
| 10 | 10 | 7 |
| 15 | 15 | 11 |
| 20 | 20 | 15 |
| 25 | 25 | 19 |
| 50 | 49 | 37 |
| 100 | 99 | 75 |
| 200 | 197 | 149 |
| 400 | 395 | 298 |
What is bhp?
Brake horsepower – or bhp – is the most widely used measure of engine power alongside PS (see below).
It’s the unit you’ll see most manufacturers using in their brochures, and it features in all of the performance charts in Which? Car reviews.
Unlike ‘horsepower’, which refers to an engine’s total output, brake horsepower only looks at the amount of energy left once other parts like the gearbox, alternator and water pump have all been powered. It's measured at the road wheels, not at the flywheel.
Powerful engines have a higher bhp figure. For example, an entry-level Toyota iQ has a 68bhp engine, while a supercharged Jaguar XF packs 503bhp.
PS explained
Though it’s still commonly used by carmakers, PS or Pferdestärke (horse-strength in German) was actually replaced by kW as the EU‘s ‘legal’ measurement of engine power in 1992.
One PS is about 98.6% of a single brake horsepower – the two are virtually interchangeable, and PS is sometimes referred to as 'metric horsepower'.
Measuring power in kilowatts
You may see some carmakers quoting the power of their engines in kilowatts – especially on the Continent – but this measurement is used far less frequently than PS or bhp. A kilowatt (kW) of power equates to around 1.34bhp.
So what is torque?
Torque refers to the amount of pulling power an engine delivers when working at different speeds. The more torque an engine has, the more pull (or acceleration) it offers at lower revs.
Torque is nearly always discussed alongside brake horsepower, as it gives clues to how quickly the engine will be able to shift the car’s weight when overtaking or pulling away from traffic lights.
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