Kilocalories Per Hour to Watts (kcal/h to W)

1 kilocalorie per hour equals 1.162222222 watts (rounded).

How to convert kilocalories per hour to watts

To convert kilocalories per hour to watts, multiply the number of kilocalories per hour by 1.162222222. The factor is rounded to 10 significant digits. To go the other way, multiply watts by 0.8604206501 (rounded).

watts = kilocalories per hour × 1.162222222

Example: 10 kilocalories per hour = 11.62222222 watts.

Several different horsepower units exist. This site lists mechanical (745.7 W), metric (735.5 W) and electrical (746 W) horsepower separately.

About these units

Kilocalorie Per Hour (kcal/h)

ScientificTraditional unit (still used in some regions)

About 1.162 watts, using the thermochemical kilocalorie (the International Table kilocalorie gives 1.163 W).

Heat output and body metabolism were long reckoned in kilocalories, so dividing by hours gave a convenient power unit for stoves, radiators and people. The kilocalorie descends from the calorie that Nicolas Clement introduced in lectures between 1819 and 1824, and the capitalized Calorie for the large unit was proposed by Marcellin Berthelot in 1879 and adopted for nutrition by Wilbur Atwater in 1887.

Which calorie is meant changes the answer. With the thermochemical kilocalorie of 4,184 joules the unit is 4,184 divided by 3,600, about 1.1622 watts, which is the figure used here. With the International Table kilocalorie of 4,186.8 joules it is exactly 1.163 watts, the same number that appears in the definition of the IT calorie as 1.163 milliwatt-hours. Either way, 60 kilocalories per hour is roughly 70 watts.

1 kilocalorie per hour = 1.162222222 watts (approximately).

Sources: Wikipedia: Calorie; NIST SP 811, Appendix B.8

Watt (W)

Metric (SI)Current unit

The SI unit of power: one joule per second. A typical LED bulb uses 5–10 W and a laptop 30–60 W.

Credit for the name goes to C. William Siemens, who proposed it in August 1882 in his presidential address to the British Association for the Advancement of Science. He chose it to honor James Watt, the Scottish inventor who in 1776 improved the Newcomen steam engine. An International Conference on Electric Units and Standards adopted Siemens' definition in London in October 1908 as the international watt. After the 1948 General Conference on Weights and Measures the unit was redefined in absolute terms, and in 1960 the 11th General Conference adopted it into the SI as the unit of power.

Today one watt is one joule per second, or equivalently one volt times one ampere. Orders-of-magnitude tables put an LED light bulb at about 7 W and an adult's basal metabolic rate at roughly 100 W. A 100 kg person climbing a 3 m ladder in 5 seconds works at about 600 W, while a laborer can sustain around 75 W over an eight-hour day. The watt measures a rate, so it says how fast energy is being used, not how much has been used in total.

The watt is the reference unit for power on this site.

Sources: Wikipedia: Watt; Wikipedia: Orders of magnitude (power)

Related conversions

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