Kilocalories to kilojoules
Type a value in either box. 1 kcal = 4.184 kJ.
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How to convert
To convert kilocalories to kilojoules, multiply by 4.184.
kJ = kcal × 4.184
For example: 500 kcal × 4.184 = 2,092 kJ.
One kilocalorie (a food "Calorie") is defined as exactly 4.184 kilojoules.
In your head: Multiply by 4 and add 5%: 500 kcal ≈ 2,100 kJ (exactly 2,092).
When you’ll need it
UK and EU food labels show both. The NHS guide figures of 2,000 kcal a day for women and 2,500 for men are about 8,400 kJ and 10,500 kJ.
Common values
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 1 kcal | 4.184 kJ |
| 10 kcal | 41.84 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 200 kcal | 836.8 kJ |
| 250 kcal | 1,046 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
| 1,500 kcal | 6,276 kJ |
| 2,000 kcal | 8,368 kJ |
| 2,500 kcal | 10,460 kJ |
| 3,000 kcal | 12,552 kJ |
Questions
- How many kilojoules are in a kilocalorie?
- 1 kilocalorie is 4.184 kilojoules.
- What is the formula to convert kilocalories to kilojoules?
- kJ = kcal × 4.184. One kilocalorie (a food "Calorie") is defined as exactly 4.184 kilojoules.
- What is 500 kilocalories in kilojoules?
- 500 kilocalories is 2,092 kilojoules.
- Is a food Calorie the same as a kilocalorie?
- Yes. The "Calories" (capital C) on food labels are kilocalories. Labels in the UK and EU usually show both kcal and kJ; 1 kcal = 4.184 kJ.