HP (Horsepower) vs PS (Pferdestärke) / kW
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
UK and US car marketing, motorbike specs everywhere, lawnmower specs in the UK.
German, French, Italian car marketing (PS); all EU type-approval; all electric vehicle specs (kW).
| Aspect | HP (Horsepower) | PS (Pferdestärke) / kW |
|---|---|---|
| Definition | 1 HP = 745.7 W (mechanical) | 1 PS = 735.5 W; 1 kW = 1000 W |
| Origin | James Watt, 1782 (Birmingham brewery horse) | Metric horsepower; SI watt |
| UK car ad | '300 bhp' | Sometimes 'kW' in small print |
| German car ad | Sometimes HP in export | '300 PS' / '221 kW' |
| EV / electric motor | Rarely HP | Always kW (sometimes PS) |
Frequently asked
Is HP the same as BHP?
In modern usage, basically yes. BHP (brake horsepower) is the power measured at the engine's output shaft using a brake dynamometer. Most modern HP figures are effectively BHP. The distinction is largely historical.
Why do German cars use PS?
Metric horsepower (Pferdestärke = 'horse strength') was defined in 1907 to align with the watt. It's slightly smaller than mechanical HP. Continental European manufacturers standardised on PS in the 1920s and never switched.
Frequently asked questions
Is HP the same as BHP?
In modern usage, basically yes. BHP (brake horsepower) is the power measured at the engine's output shaft using a brake dynamometer. Most modern HP figures are effectively BHP. The distinction is largely historical.
Why do German cars use PS?
Metric horsepower (Pferdestärke = 'horse strength') was defined in 1907 to align with the watt. It's slightly smaller than mechanical HP. Continental European manufacturers standardised on PS in the 1920s and never switched.