Horsepower to Kilowatts: Converting Engine Power

Engine power gets listed sometimes in horsepower (hp), sometimes in kilowatts (kW) — on vehicle registration documents, manufacturer specs, and tax calculations. The numbers look different for the same engine, which trips people up. Let's sort out how to convert between them.

How many kW in one horsepower

1 hp ≈ 0.7355 kW, and going the other way, 1 kW ≈ 1.3596 hp.

One important nuance: there are several definitions of horsepower (metric, mechanical/imperial, electrical) that differ slightly from one another. Most of Europe uses metric horsepower (0.7355 kW) for cars — that's the figure that shows up on registration documents and in most technical specs.

Conversion formulas

From horsepower to kilowatts:

kW = hp × 0.7355

From kilowatts to horsepower:

hp = kW × 1.3596

For example, a 150 hp engine is 150 × 0.7355 ≈ 110.3 kW. And 100 kW is 100 × 1.3596 ≈ 136 hp.

Table of common values

Why this matters

Kilowatts show up in European catalogs and on many registration documents, while some countries calculate vehicle tax based on horsepower — so comparing imported vehicles or handling customs paperwork often means converting one to the other. Engineers and developers also need kilowatts for calculations involving electric motors and general power ratings.

Converting online

Instead of memorizing the 0.7355 coefficient, use the power converter — it converts between watts, kilowatts, megawatts, horsepower, and BTU/h. Enter a value in any field and the rest update instantly.