How to convert kilocalories to joules
To convert a measurement in kilocalories to joules, multiply the value by 4,184. The conversion factor comes from the relationship between both units and the joule.
For example, to convert 5 kcal to joules: 5 × 4,184 = 20,920 J.
What is a kilocalorie?
A kilocalorie equals 1,000 small calories, or exactly 4,184 joules, and is the 'Calorie' shown on food nutrition labels. The food Calorie (capital C) is actually a kilocalorie. This convention, established in nutrition science, means a 500-Calorie meal contains 500 kilocalories, or about 2,092 kilojoules.
Common uses of kilocalories include: Food energy (the dietary 'Calorie'); Metabolism and exercise burn estimates; Nutrition and diet planning; Bomb-calorimetry food testing.
What is a joule?
A joule is the SI derived unit of energy, equal to the work done when a force of one newton moves an object one meter (1 N·m). Named after the English physicist James Prescott Joule, who established the mechanical equivalent of heat in the 1840s. The joule became the SI standard for all forms of energy, work, and heat.
Common uses of joules include: Scientific and engineering energy calculations; Nutrition labeling in metric countries; Mechanical work and kinetic energy; Electrical energy in physics (watt-seconds).
Kilocalories to joules worked examples
Here are some common values converted:
1 kcal = 4,184 J 5 kcal = 20,920 J 10 kcal = 41,840 J 50 kcal = 209,200 J 100 kcal = 418,400 J
Frequently asked questions
How many joules are in one kilocalorie?
One kilocalorie (kcal) equals 4,184 joules (J). Multiply any value in kilocalories by 4,184 to convert to joules.
How do I convert kilocalories to joules?
Multiply the value in kilocalories by 4,184. For example, 5 kcal × 4,184 = 20,920 J.
How do I convert joules to kilocalories?
Multiply the value in joules by 0.000239005736, or divide by 4,184. Use the swap button on the converter above to reverse the direction.
Is the kilocalorie to joule conversion exact?
The thermochemical calorie is defined as exactly 4.184 J and the BTU as 1055.056 J. Conversions between SI energy units are exact.
What is the formula for kilocalories to joules?
The formula is: J = kcal × 4,184. This comes from the definition of both units relative to the joule.