HP to kW Conversion Chart

One mechanical horsepower is 0.745699872 kilowatts. Most references round this to 0.7457, which is accurate to better than one part in a million — far tighter than any engine is measured. This page gives the full conversion table plus the exact factor for when it matters.

Motor Sizes: 1 to 100 HP

Standard industrial motor ratings. These are the sizes you will find on nameplates and in supplier catalogues.

Car and Engine Outputs: 100 to 1000 HP

The range most vehicle specifications fall into. Note that European brochures usually quote PS rather than mechanical HP — the third column shows the difference, which grows to about 14 units at the 1000 HP end.

The Exact Conversion Factor

Mechanical horsepower is defined as 550 foot-pounds per second. Working that through in SI units gives exactly 745.699871582270222 watts, which is where 0.7457 kW comes from. The definition is exact rather than measured, because both the foot and the pound are themselves defined exactly in metric terms.

Where people go wrong is assuming there is only one horsepower. There are several, and they differ by more than the rounding:

The gap between mechanical and metric horsepower is about 1.4%, which is why the same car is quoted as 150 PS in Germany and 148 hp in Britain. Boiler horsepower is a different quantity entirely and is not interchangeable with any of the others — see our boiler horsepower calculator for that.

Quick Reference Points Worth Memorising

• 1 HP ≈ 0.75 kW — accurate to within 0.6%, good enough for mental arithmetic.
• 100 HP ≈ 75 kW — the same shortcut scaled up.
• 1 kW ≈ 1.34 HP — the reverse.
• 200 HP = 149 kW — a common car figure worth anchoring on.

For single conversions use our HP to kW calculator or kW to HP. If your source quotes PS, KM or KS rather than mechanical horsepower, the kW to PS converter handles that scale, and the horsepower unit converter covers every unit at once.