Quick answer
J = cal × 4.184 and J = kcal × 4,184. For example, 100 cal = 418.4 J, and 1 kcal = 4,184 J.
Calories to joules table
| Calories | Joules | Kilojoules |
|---|---|---|
| 1 cal | 4.184 J | 0.004184 kJ |
| 10 cal | 41.84 J | 0.0418 kJ |
| 100 cal | 418.4 J | 0.4184 kJ |
| 1,000 cal | 4,184 J | 4.184 kJ |
| 4,184 cal | 17,505.9 J | 17.506 kJ |
| 1 kcal | 4,184 J | 4.184 kJ |
| 2,000 kcal | 8,368,000 J | 8,368 kJ |
Which calorie do you mean?
The tool defaults to small calories (cal) because that is what the word means in physics and chemistry. If you have a food label in mind, change the unit to Calories (kcal) or use the calories to kJ converter. The kJ vs calories guide explains the difference.
Frequently asked questions
How many joules are in 1 calorie?
One small calorie is 4.184 joules.
How many joules are in 2,000 kcal?
2,000 kcal is 8,368,000 J, which is 8,368 kJ.
what is a calorie in joules?
One calorie (cal) is equal to 4.184 joules (J). A calorie measures energy, while a joule is the standard SI unit of energy. To convert calories to joules, multiply the number of calories by 4.184. For example, 10 calories equal 41.84 joules. Use our calories to joules converter to calculate energy values quickly and accurately.
Last updated 15 Oct 2026. How we calculate.