Convert kJ and kcal in either direction
1 kilocalorie (kcal) equals 4.184 kilojoules (kJ). Divide kJ by 4.184 to get kcal, or multiply kcal by 4.184 to get kJ. So 1,000 kJ is approximately 239 kcal, and 100 kcal is 418.4 kJ. In everyday conversation about food, ‘calories’ means kilocalories.
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Convert kilojoules and kilocalories
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1 kcal = 4.184 kJ. Only the displayed result is rounded. Sources: NIST conversion factors and EU food information rules.
How many kcal are in … kJ?
Common nutrition-label values converted using 4.184, with kcal rounded to whole numbers.
| Kilojoules (kJ) | Kilocalories (kcal) |
|---|---|
| 100 kJ | 24 kcal |
| 500 kJ | 120 kcal |
| 1,000 kJ | 239 kcal |
| 1,550 kJ | 370 kcal |
| 2,000 kJ | 478 kcal |
| 8,400 kJ | 2,008 kcal |
Why do labels show both kJ and kcal?
EU food information rules (Regulation 1169/2011) use both kilojoules and kilocalories for energy declarations. The adult reference intake shown on EU labels is 8,400 kJ / 2,000 kcal. These are rounded reference values: a direct conversion of 8,400 kJ gives approximately 2,008 kcal. Labelling conventions vary by country.
Is a calorie the same as a kilocalorie?
Strictly speaking, a kilocalorie is 1,000 small calories. In everyday food discussions, ‘calorie’ usually means a kilocalorie. A recipe with 250 food calories contains 250 kcal, or 1,046 kJ.
Frequently asked questions
How do I convert kJ to kcal?
Divide by 4.184. For example, 1,550 kJ ÷ 4.184 is approximately 370 kcal.
How do I convert kcal to kJ?
Multiply by 4.184. For example, 370 kcal × 4.184 is approximately 1,548 kJ. It does not return exactly 1,550 because 370 kcal was already rounded.
How many kJ do I need each day?
Individual needs vary with body size, age and activity. The EU label reference of 8,400 kJ (2,000 kcal) is not a personal target. The daily calorie calculator can provide an estimate.