ucUnitCloudInternational unit matrix

Mistake guide

Equating PS, kW and hp

PS, kW and hp are three names for the same number.

01Assumption

PS, kW and hp are three names for the same number.

02Actually

They are three different units: 1 PS = 735.49875 W, 1 hp = 745.6998715822702 W, 1 kW = 1000 W. A 150 PS engine produces about 110 kW, a 150 hp engine about 112 kW.

03Why

PS is the metric horsepower, hp the mechanical horsepower of the Anglo-American system. Both trace back to early measurements of horse power but were fixed using different foot and pound definitions.

04Check

Always read the unit attached to the figure and never interpolate between PS and hp. For vehicle comparisons kW is the most unambiguous figure because it is defined within the SI.

Matching conversions

Metric horsepower to KilowattPS → kWPowerKilowatt to Metric horsepowerkW → PSPowerMetric horsepower to Mechanical horsepowerPS → hpPowerMechanical horsepower to Metric horsepowerhp → PSPowerKilowatt to Mechanical horsepowerkW → hpPower

Unit family: Power

Sources

BIPM SI BrochureSI base units, prefixes and official SI context.NIST Guide to SI Appendix BNIST conversion-factor method and non-SI factors.
When not to use

Do not use as the sole basis for official, medical, safety-critical or contractual decisions.

Citation

Citation note: UnitCloud, mistake guide, sources reviewed: September 2026. Source basis: BIPM SI Brochure · NIST Guide to SI Appendix B.