CalcPairsCalories to Kilojoules Converter (kcal to kJ)
A 500 kcal meal is 2,092 kJ. One food Calorie — properly a kilocalorie — is exactly 4.184 kJ, so kcal × 4.184 gives kilojoules. The 2,000 kcal reference day on US labels is 8,368 kJ on Australian ones.
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How this conversion works
Food labels in the US lead with Calories; in Australia, New Zealand and much of Europe they lead with kilojoules, and many packages print both. Type either side to translate a label: a 250 kcal snack bar is 1,046 kJ; a 2,500 kJ lunch is 597.5 kcal.
Mind the capital letter: a food 'Calorie' is a kilocalorie — a thousand of the small calories of physics class. Nobody's snack contains 500 small calories (that would be half a kilocalorie, the energy in a crumb). This page converts the food unit, kcal, throughout.
The exact formula
kilojoules = kilocalories × 4.184
The thermochemical calorie is defined as exactly 4.184 joules, making the kilocalorie exactly 4.184 kJ. The reverse is kilocalories = kilojoules ÷ 4.184.
Kilocalories to Kilojoules conversion table
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 50 | 209.2 |
| 100 | 418.4 |
| 150 | 627.6 |
| 200 | 836.8 |
| 250 | 1046 |
| 300 | 1255.2 |
| 350 | 1464.4 |
| 400 | 1673.6 |
| 450 | 1882.8 |
| 500 | 2092 |
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 600 | 2510.4 |
| 700 | 2928.8 |
| 800 | 3347.2 |
| 900 | 3765.6 |
| 1000 | 4184 |
| 1500 | 6276 |
| 2000 | 8368 |
| 2500 | 10,460 |
Frequently asked questions
How many kJ are in 100 calories?
418.4 kJ — reading 'calories' as food Calories (kcal), as labels mean it.
Why do labels say kcal but call it Calories?
History: nineteenth-century writers capitalised the kilocalorie into 'Calories' for food, and the usage stuck. The label's fine print — kcal — is the true unit.
How many kcal should I eat a day, in kJ?
Reference intakes are 2,000 kcal = 8,368 kJ for an average adult woman and 2,500 kcal = 10,460 kJ for a man, as printed on labels; individual needs vary widely.