What does kilowatt mean?
A kilowatt is a unit of power equal to 1,000 watts. It is used to describe the output of engines, generators, solar panels, appliances, and other equipment, especially when a more convenient scale than watts is needed. The abbreviation is kW. Although the word is common in technical contexts, people also use it in everyday descriptions of household and industrial machinery. A kilowatt should not be confused with a kilowatt-hour: the former measures the rate at which energy is produced, supplied, or used, while the latter measures the total energy used over a period of time. This distinction is important for electricity bills and energy calculations. The term is part of the international SI system and is understood in British, American, and other English-language varieties.
nounA unit of power equal to 1,000 watts, commonly used for the output of engines, generators, appliances, and other machinery. It is abbreviated kW.
- A unit of power equal to 1,000 watts, used especially to describe the power output or consumption of electrical and mechanical systems.
"The solar installation has a maximum capacity of 5 kilowatts."
"The wind turbine can generate up to 2.5 kilowatts of electricity."
"The laboratory purchased a laser rated at 500 watts rather than a kilowatt because its lower power was sufficient."
The standard plural is kilowatts, written without an apostrophe.
"The backup generator provides enough power for several kilowatts of equipment."
A kilowatt tells you how fast energy is being used; a kilowatt-hour tells you how much energy is used over time.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does kilowatt come from?
The word combines the prefix kilo-, meaning one thousand and derived from the Greek khiloi, 'thousand', with watt, the unit named after the Scottish engineer and physicist James Watt. Watts had become established as the standard unit of power by the late 19th century, and the larger unit kilowatt was adopted for practical measurements where values in thousands of watts were common. The compound follows the standard construction of SI units, in which decimal multiples are formed by attaching an approved prefix to the base unit.
How kilowatt is actually used
The abbreviation kW is standard in technical and commercial contexts. In everyday speech, the plural kilowatts is often used when stating the power of an appliance or machine, although the technically precise term is kilowatts of power.
Easily confused with kilowatt
A watt is the base SI unit of power, whereas a kilowatt is a larger unit equal to 1,000 watts.
A kilowatt measures power, or the rate of energy use, while a kilowatt-hour measures energy consumed over time.