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Convert kJ to kcal

Please provide values below to convert kilojoule [kJ] to kilocalorie (th) [kcal (th)], or vice versa.



Definition: The kilojoule is an SI (International System of Units) derived unit of energy that is equal to 1000 joules. The joule is defined as the amount of energy transferred to an object when a one newton force acts on an object in the direction movement through a distance of one meter.

History/origin: The kilojoule, like other SI derived units, uses SI prefixes to denote multiples or submultiples of the given unit. In this case, the prefix "kilo" is used to express a multiple of 1000.

Current use: In countries that have adopted SI, the kilojoule is widely used as a unit of food energy. In some cases, both kilojoules and kilocalories are displayed, though in countries such as the United States, only kilocalories are shown (often referred to as "Calories") on food labels. Aside from this everyday use, kilojoules are used within scientific contexts around the world.


Definition: A kilocalorie (symbol: kcal or Cal) is a unit of energy defined based on the calorie and is equal to 1000 calories or 4.1868 kilojoules. A calorie (small calorie) is defined as the amount of energy required to increase the temperature of one gram of water by one °C. Kilocalories are also referred to as large calories or food calories, and are sometimes referred to as Calories, which can be ambiguous, and mistaken for the small calorie.

History/origin: The kilocalorie shares its origin with the small calorie except that it is defined in terms of the kilogram rather than the gram. The term is based on the Latin "calor," meaning heat, and the calorie was first defined as a unit of heat energy in 1824 by Nicolas Clement. The kilocalorie however, was not introduced to the American public until 1887, by Wilbur Olin Atwater.

Current use: Although the kilocalorie is generally considered an obsolete unit, it is still widely used alongside the SI unit of kilojoule to measure food energy. In countries where SI has not been adopted, such as the US, kilocalories, typically referred to as simply "Calories," are still the preferred measurement of food energy. Kilocalories are also sometimes seen in chemistry.

The kilo prefix is based on the SI prefixes, but calories with prefixes beyond the multiple of kilo are not commonly used.

Kilojoule to Kilocalorie (th) Conversion Table

Kilojoule [kJ]Kilocalorie (th) [kcal (th)]
0.01 kJ0.0023900574 kcal (th)
0.1 kJ0.0239005736 kcal (th)
1 kJ0.2390057361 kcal (th)
2 kJ0.4780114723 kcal (th)
3 kJ0.7170172084 kcal (th)
5 kJ1.1950286807 kcal (th)
10 kJ2.3900573614 kcal (th)
20 kJ4.7801147228 kcal (th)
50 kJ11.9502868069 kcal (th)
100 kJ23.9005736138 kcal (th)
1000 kJ239.0057361377 kcal (th)

How to Convert Kilojoule to Kilocalorie (th)

1 kJ = 0.2390057361 kcal (th)
1 kcal (th) = 4.184 kJ

Example: convert 15 kJ to kcal (th):
15 kJ = 15 × 0.2390057361 kcal (th) = 3.5850860421 kcal (th)

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