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Difference between european Ps (metric) and american Hp (imperial) Horsepower

PS vs HP What's the Difference?

When talking about engine power, two terms are commonly used: PS and HP. While they are often used interchangeably, they are not exactly the same. The difference lies in their origin, definition, and measurement

What is PS (Pferdestärke)?

PS stands for Pferdestärke, which is the metric unit of horsepower commonly used in Europe and parts of Asia. It was originally defined as the power required to lift a 75-kilogram mass one meter in one second.

1 PS ≈ 735.5 watts Used mainly in Europe Metric-based unit Also known as "metric horsepower"

What is HP (Horsepower)?

HP, or horsepower, is the imperial unit of power, originally defined by James Watt. It represents the power needed to lift 550 pounds by one foot per second.

1 HP ≈ 746 watts Commonly used in the USA and the UK Slightly stronger than PS

Key Difference Between PS and HP

Although both units measure engine power, HP is slightly more powerful than PS.

HP ≈ 1.014 Ps

1 PS ≈ 0.986 HP

This means that an engine rated at 100 PS produces about 98.6 HP, while 100 HP equals roughly 101.4 PS.

In everyday use, the difference is small and often negligible, but it becomes relevant when comparing specifications from different markets.

What About Kilowatts (kW)?

Today, kilowatt (kW) is the official SI unit of power and is increasingly used in technical and legal documentation worldwide.

1 PS ≈ 0.735 kW

1 HP ≈ 0.746 kW

Many manufacturers now list engine power in kW alongside PS or HP to provide a standardized reference.

Conclusion

PS and HP measure the same concept — engine power — but are based on different measurement systems.

PS is metric and slightly weaker, while HP is imperial and slightly stronger. Although the difference is small, understanding it helps when comparing vehicles across different regions.

In modern specifications, kilowatts (kW) provide the most accurate and internationally standardized way to express power.