European registration documents show engine power in kW, car buyers talk in PS (horsepower), and American sports cars are marketed in HP (horsepower) — three units for the same physical quantity. The kW-to-HP converter switches instantly between kilowatts, metric horsepower (PS), and imperial horsepower (HP), which is especially useful when comparing imported vehicles or checking motorcycle licence limits.
Step by Step: How to Use the kW to HP Converter
- Enter the source value: Type in the known engine output — e.g. 110 from a registration document (in kW) or 150 from an advertisement (in PS).
- Select the source unit: kW (European registration document), PS (metric, German), or HP (imperial, US market). 1 PS = 0.7355 kW; 1 HP = 0.7457 kW — the difference between PS and HP is about 1.4%.
- Read the result: The calculator displays all three units simultaneously, allowing direct comparison.
- Check licence power limits: Motorcycle category A2: max. 35 kW = 47.6 PS. Category A (unrestricted): above 35 kW. Moped licence AM: max. 4 kW.
- Calculate power-to-weight ratio: Many sports car enthusiasts divide PS by kerb weight in kg — e.g. 510 PS ÷ 1,730 kg (BMW M3) = 0.295 PS/kg.
Practical Examples
Example 1 – Compact car comparison: VW Golf 8 with 110 PS = 110 × 0.7355 = 80.9 kW. The registration document shows 81 kW. The same model with 150 PS = 110.3 kW — the difference matches exactly between the two engine variants.
Example 2 – Electric car Tesla Model 3 Long Range: Tesla quotes 366 kW (498 PS) system output. That is 366 × 1.3596 = 497.8 PS — EV makers often use rounded PS figures for marketing purposes.
Example 3 – Motorcycle licence A2: The 35 kW limit for category A2 corresponds to 35 × 1.3596 = 47.6 PS. A motorcycle with 48 PS would no longer be eligible for A2.
kW to PS/HP Conversion
1 PS = 0.7355 kW; 1 kW = 1.3596 PS. Examples: VW Golf 110 PS = 80.9 kW; BMW M3 510 PS = 375.1 kW; Tesla Model 3 Long Range 498 PS = 366.3 kW. Motorcycle 50 kW = 68 PS (A2 licence limit).
Frequently Asked Questions (FAQ)
What is the difference between PS and HP?
PS (Pferdestärke) is the metric unit: 1 PS = 0.7355 kW. HP (Horsepower) is the imperial unit: 1 HP = 0.7457 kW. The difference is 1.38% — at 500 PS/HP this means roughly 7 PS deviation when comparing American and European vehicle specs.
Why do German registration documents show kW instead of PS?
The EU has required kW as the SI unit since 1992. PS is a non-SI unit and is only permitted in the EU as an additional figure. Registration documents therefore show kW, while advertising and everyday speech continue to use PS.
Does the maximum system power for hybrid vehicles match the PS figure?
Not always directly. For plug-in hybrids, manufacturers sometimes add the combustion engine and electric motor outputs in the PS figure, even though both never operate at full load simultaneously. The system power measured to ISO 1585 is the basis for the registration document entry.
