kcal to kJ Converter
Type a value in kilocalories to see it in kilojoules as you type, with the exact formula and a reference chart.
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How this was calculated
- 1 kilocalorie = 4.184 kilojoules
- 500 × 4.184 = 2,092 kJ
| kcal | kJ |
|---|---|
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 150 kcal | 627.6 kJ |
| 200 kcal | 836.8 kJ |
| 250 kcal | 1,046 kJ |
| 300 kcal | 1,255.2 kJ |
| 350 kcal | 1,464.4 kJ |
| 400 kcal | 1,673.6 kJ |
| 500 kcal | 2,092 kJ |
| 600 kcal | 2,510.4 kJ |
| 700 kcal | 2,928.8 kJ |
| 800 kcal | 3,347.2 kJ |
| 1,000 kcal | 4,184 kJ |
| 1,200 kcal | 5,020.8 kJ |
| 1,500 kcal | 6,276 kJ |
| 1,800 kcal | 7,531.2 kJ |
| 2,000 kcal | 8,368 kJ |
| 2,200 kcal | 9,204.8 kJ |
| 2,500 kcal | 10,460 kJ |
| 3,000 kcal | 12,552 kJ |
| 3,500 kcal | 14,644 kJ |
| 5,000 kcal | 20,920 kJ |
| kJ | kcal |
|---|---|
| 50 kJ | 11.9503 kcal |
| 100 kJ | 23.9006 kcal |
| 200 kJ | 47.8011 kcal |
| 250 kJ | 59.7514 kcal |
| 300 kJ | 71.7017 kcal |
| 400 kJ | 95.6023 kcal |
| 500 kJ | 119.503 kcal |
| 600 kJ | 143.403 kcal |
| 750 kJ | 179.254 kcal |
| 800 kJ | 191.205 kcal |
| 1,000 kJ | 239.006 kcal |
| 1,200 kJ | 286.807 kcal |
How to convert kilocalories to kilojoules
1 kilocalorie = 4.184 kilojoules. To convert kilocalories to kilojoules, multiply by 4.184. A kilocalorie (the food Calorie) is 1,000 thermochemical calories, exactly 4,184 J. A kilojoule is 1,000 joules; food labels in Australia, New Zealand and the EU list energy in kJ.
Worked examples
- 100 kilocalories = 418.4 kJ (100 × 4.184)
- 500 kilocalories = 2,092 kJ (500 × 4.184)
- 2,000 kilocalories = 8,368 kJ (2,000 × 4.184)
Where this conversion comes up
Kilocalories are used for nutrition labels, diet plans and fitness trackers; kilojoules for food labels outside the US and exercise machines. Multiply by 4.184: a 2,000 kcal diet is 8,368 kJ and a 100 kcal snack is 418 kJ. Treadmills and fitness apps may show either, and on labels 'Calories' and kcal are the same.
Quick estimate
Multiply by 4.2 (0.4% high), or by 4 and add 4.6%.
Common mistakes
- Dividing instead of multiplying. A kilojoule is smaller than a kilocalorie, so the number of kilojoules must come out larger: 100 kilocalories = 418.4 kJ.
- Rounding too early. Keep the full factor until the last step; rounding 4.18 to 4.2 first puts large values noticeably off.
Going the other way? Use the kj to kcal converter. Related energy converters: kj to calories.
Frequently asked questions
How do you convert kilocalories to kilojoules?
Multiply the kilocalories by 4.184. For example, 500 kilocalories is 2,092 kilojoules.
How many kilojoules are in one kilocalorie?
One kilocalorie is 4.184 kilojoules. A kilocalorie (the food Calorie) is 1,000 thermochemical calories, exactly 4,184 J.
What is 2,000 kilocalories in kilojoules?
2,000 kilocalories is 8,368 kilojoules.
Is there a quick way to estimate kilocalories to kilojoules?
Multiply by 4.2 (0.4% high), or by 4 and add 4.6%.