Direct conversion
Convert calorie [cal] to kilojoule [kJ] instantly with formula, examples, chart, and FAQs.
Quick answer
Use the calculator below for any custom value, then check the formula, examples, chart, and reverse conversion links.
1 calorie [cal] = 0.004184 kilojoule [kJ]
1 calorie [cal] = 0.004184 kilojoule [kJ]
Example: 1 calorie [cal] equals 0.004184 kilojoule [kJ].
Energy conversions use joule as the reference unit, including electrical, thermal, nutrition, and mechanical energy units.
Displayed results are rounded for readability. The calculator keeps enough precision for everyday use and switches to scientific notation for very large or very small values. Last reviewed: 2026-05-21.
The calorie is an energy unit traditionally based on heating water by one degree Celsius.
HistoryCalories were used in heat measurement before joules became the SI standard.
Current useCalories are used in nutrition, food labels, exercise estimates, and diet planning.
The kilojoule is an energy unit equal to 1000 joules.
HistoryKilojoules are a metric multiple of joules and became common where joules are too small.
Current useKilojoules are used for food energy labels, thermodynamics, exercise energy, and engineering calculations.
| calorie [cal] | kilojoule [kJ] |
|---|---|
| 1 | 0.004184 |
| 2 | 0.008368 |
| 5 | 0.02092 |
| 10 | 0.04184 |
| 20 | 0.08368 |
| 25 | 0.1046 |
| 50 | 0.2092 |
| 100 | 0.4184 |
| 1000 | 4.184 |
Use this formula: 1 calorie [cal] = 0.004184 kilojoule [kJ] Enter your value in the calculator and the result updates instantly.
1 calorie [cal] equals 0.004184 kilojoule [kJ].
Yes. Use the swap button in the calculator or open the related reverse conversion link when it is listed on this page.