The Three Types of Horsepower
Not all horsepower is equal. The definition you use matters when comparing car specs across different markets.
- Mechanical HP (bhp): 1 HP = 745.7 W. Used by US and UK manufacturers. Also called SAE horsepower.
- Metric HP (PS / CV / ch): 1 PS = 735.5 W. Used by German, French, Italian, Japanese, and Korean manufacturers. About 1.4% less than mechanical HP.
- Electrical HP: 1 HP = 746 W exactly. Used for electric motors, pumps, and industrial equipment. Virtually identical to mechanical.
- When a German car says 300 PS, that's ~296 mechanical HP — close but not the same.
HP to kW Reference Table
Common conversion reference points for car buyers and tuners:
- 100 HP = 74.6 kW (EU city car territory)
- 150 HP / 148 PS ≈ 110-112 kW (compact mainstream)
- 200 HP / 203 PS ≈ 149 kW (hot hatch / sport compact)
- 300 HP / 304 PS ≈ 224 kW (sports car territory)
- 400 HP / 406 PS ≈ 298 kW (muscle car / high-performance)
- 500 HP / 507 PS ≈ 373 kW (supercar entry point)
Why European Cars Look More Powerful
A German manufacturer quoting 300 PS and a US manufacturer quoting 296 bhp are describing almost identical cars — but the German figure sounds bigger. Many EU manufacturers also quote at the wheels (whp) vs. the crank, further complicating comparisons.
- PS to HP: multiply PS × 0.9863 for mechanical HP
- Crank HP vs wheel HP: drivetrain losses eat 10-20% — a 300 hp engine delivers ~240-270 whp at the wheels
- hp vs bhp vs whp: bhp = brake HP at crank; whp = wheel HP after drivetrain loss
- Always compare at the same measurement point (crank or wheels) to be fair