Power Converter

How these units are defined

The watt is one joule per second. Mechanical horsepower is 550 foot-pound-force per second, which is 745.69987 W.

Worked examples

• 1 Watt = 0.001 Kilowatt
• 10 Watt = 0.01 Kilowatt
• 100 Watt = 0.1 Kilowatt

Common mistakes

• •Horsepower comes in several sizes: mechanical (745.7 W), metric/PS (735.5 W) and electrical (746 W). Car specifications in Europe and Japan usually quote PS.
• •Power (W) is a rate; energy (Wh, J) is power × time.

Power conversions

Sources for these factors

1. Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
2. The International System of Units (SI Brochure), 9th edition — BIPM

Last reviewed 26 October 2026 against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy

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