Convert kW to Horsepower (hp) and PS

This converter turns a power value between kilowatts, metric horsepower (PS, also written CV or ch) and mechanical horsepower (hp): choose the two units, type a value, and the other field updates at once. Use it to read a car or motorcycle spec sheet given in another unit, to compare a European and an American engine, or to relate a power in kW to the familiar idea of horsepower.

The kilowatt (1 kW = 1,000 W) is the official SI unit of power and the figure printed on European vehicle registration papers (field P.2). Metric horsepower (PS in German, CV in Spanish and Italian, ch in French) is defined by the German standard DIN 66036: the power that lifts 75 kg by 1 m in 1 s, that is 75 × 9.80665 = 735.49875 W exactly. Mechanical horsepower (hp) is James Watt's horse: 550 foot-pounds per second, or 745.699872 W.

The formulas: PS = kW × 1.359622 (or kW ÷ 0.73549875); hp = kW × 1.341022 (or kW ÷ 0.745699872); kW = PS × 0.73549875; kW = hp × 0.745699872. Between the two horsepowers, 1 PS = 0.98632 hp and 1 hp = 1.01387 PS: a gap of 1.4%. The selectors on both sides let you go from any unit to any other.

For a mental estimate, multiply kW by 1.34 to get hp: 100 kW ≈ 134 hp (exact 134.10). For metric horsepower use 1.36: 100 kW ≈ 136 PS (exact 135.96). In reverse, multiply hp by 0.75 or drop about 25%: 200 hp ≈ 150 kW (exact 149.14).

Do not mix up metric horsepower (735.5 W) with mechanical horsepower (745.7 W), with the US electrical horsepower (exactly 746 W) or with boiler horsepower (9,809.5 W). In the UK, bhp (brake horsepower) is power measured at the crankshaft and is in practice mechanical hp. French "CV fiscaux" and similar tax horsepower figures in other countries are not power units at all: they are administrative ratings used for taxation.