Power Conversions

power conversions
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Select a unit of power

What is power?

Power is the rate at which energy is transformed or work is done. The standard derived unit of power in the International System of Units (SI) is the watt (W). Other units of power commonly in use throughout the world include kilowatts (kW), megawatts (MW), gigawatts (GW), British thermal units per hour (BTU/h), Celsius heat units per hour (CHU/h), calories per hour (cal/h), calories per day (cal/d), kilocalories per hour (kcal/h), foot-pound-force per second ( ft lbf/s), inch-pound-force per second (in lbf/s), liter-atmosphere per second (L atm/s) and horsepower (hp).

Common power conversions

  • 1 watt (W) = 1,000 milliwatts (mW) = 1,000,000 microwatts (μW)
  • 1 kilowatt (kW) = 1,000 watts (W) = 1,000,000 milliwatts (mW)
  • 1 gigawatt (GW) = 1,000 kilowatts (kW) = 1,000,000 watts (W)
  • 1 horsepower (metric) (hp) = 735.49875 watts (W) = 0.73549875 kilowatts (kW)
  • 1 British thermal unit (IT) per hour (BTU/h) = 0.29307107 watts (W)
  • 1 British thermal unit (59 °F) per hour (BTU/h) = 0.293001111 watts (W)
  • 1 calorie (IT) per hour (cal/h) = 0.001163 watts (W)
  • 1 erg per second (erg/s) = 10-7 watts (W)
  • 1 foot-pound-force per second (ft lbf/s) = 1.355817948 watts (W)
  • 1 ton of refrigeration (IT) (RT) = 3,516.853 watts (W)

Subdivisions and multiples of the watt using SI prefixes

Subdivisions of the watt Multiples of the watt
Name Symbol Value Name Symbol Value
deciwatt dW 10-1 W decawatt daW 101 W
centiwatt cW 10-2 W hectowatt hW 102 W
milliwatt mW 10-3 W kilowatt kW 103 W
microwatt μW 10-6 W megawatt MW 106 W
nanowatt nW 10-9 W gigawatt GW 109 W
picowatt pW 10-12 W terawatt TW 1012 W
femtowatt fW 10-15 W petawatt PW 1015 W
attowatt aW 10-18 W exawatt EW 1018 W
zeptowatt zW 10-21 W zettawatt ZW 1021 W
yoctowatt yW 10-24 W yottawatt YW 1024 W

Converting power units: several links

A list with conversions for power units utilized in various technical and scientific fields is listed below.