Kilocalories to Kilowatt-hours (kcal to kWh)

1 kilocalorie equals 0.001162222222 kilowatt-hours (rounded).

1 kilocalorie = 0.001162222222 kilowatt-hours

How to convert kilocalories to kilowatt-hours

To convert kilocalories to kilowatt-hours, multiply the number of kilocalories by 0.001162222222. The factor is rounded to 10 significant digits. To go the other way, multiply kilowatt-hours by 860.4206501 (rounded).

kilowatt-hours = kilocalories × 0.001162222222

Example: 10 kilocalories = 0.01162222222 kilowatt-hours.

The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.

About these units

Kilocalorie (kcal)

ScientificTraditional unit (still used in some regions)

1,000 thermochemical calories (4,184 J). The 'Calorie' on food labels in North America.

Marcellin Berthelot separated the gram calorie from the kilogram calorie in 1879, and the American chemist Wilbur Atwater adopted a capital-C Calorie for the large unit in 1887 in a widely read article on the energy in food. Joseph Howard Raymond proposed the term kilocalorie in his 1894 textbook. The two names now describe the same quantity, 1,000 small calories, which at the thermochemical value is 4,184 J or 4.184 kJ.

Food labels carry the unit today, though practice differs by region. North American labels use kilocalories almost exclusively, European labels show kilojoules and kilocalories together under EU Regulation 1169/2011, and Chinese labels give kilojoules only. Typical energy contents are about 9 kcal per gram for fat, about 4 for carbohydrate and protein, and about 7 for alcohol. In electrical terms, 4,184 J works out to about 1.162 watt-hours, since one watt-hour is 3,600 J. NIST also lists a kilocalorie based on the International Table calorie, which is 4,186.8 J.

1 kilocalorie = 4,184 joules (exactly).

Sources: Wikipedia: Calorie (includes kilocalorie); NIST SP 811, Appendix B.8 (energy conversion factors)

Kilowatt-hour (kWh)

Metric (SI)Current unit

3.6 million joules, the energy used by a 1,000-watt appliance in an hour. The billing unit for household electricity.

Before it was a line on every power bill, the kilowatt-hour had a British nickname: the Board of Trade unit, abbreviated B.T.U. after the government body that regulated the electricity industry until 1942, when the Ministry of Power took over. In India it is still often called simply a unit, and a million of them, written MU, is a gigawatt-hour.

A kilowatt-hour is the energy of a 1 kW device running for an hour, which is 3.6 MJ, or about 3,412 British thermal units. A 100 W television watched for 10 hours uses one, and boiling a liter of water in an electric kettle takes about 0.1. In 2020 the average US household used 893 kWh a month, an average continuous draw of about 1.22 kW.

Utilities multiply the kilowatt-hours consumed by a price per kWh, and larger customers may also pay for peak demand. One common error is writing kW/h, which would mean kilowatts per hour, a rate of change of power, not energy.

1 kilowatt-hour = 3,600,000 joules (exactly).

Sources: Wikipedia: Kilowatt-hour; Wikipedia: British thermal unit; Wikipedia: Watt-hour

Related conversions

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