Watts (W)

The watt (W) is the SI unit of power, defined as one joule per second (1 W = 1 J/s). It measures the rate of energy transfer or conversion. The watt is named after James Watt and standardized by the BIPM according to the International System of Units [bipm-si-brochure].

Origin

Named after engineer James Watt in the late 19th century, the watt was adopted officially by the CIPM and BIPM to quantify mechanical and electrical power consistently. It became part of the SI base units in 1960 [bipm-si-brochure].

Worldwide Use

Watts measure power output and consumption in electrical, mechanical, and thermal systems globally. It is used across industries, including electronics, automotive, and power generation, following ISO and NIST standards [nist-sp-811].

Common References

  • A standard LED bulb typically consumes 10 W
  • Household microwave ovens operate around 700–1200 W
  • Small wind turbines produce from 400 W to several kW