Calories to Kilojoules converter

To convert calories to kilojoules, enter the value in the first field. The result in kilojoules is calculated automatically using the exact conversion factor.

1 cal = 0.004184 kJ
1 kJ ≈ 239.005736138 cal

Formula: kJ = cal × 0.004184
cal ≈ kJ × 239.005736138

Definitions: 1 cal = 4.184 J; 1 kJ = 1000 J

The calorie (cal) here is the thermochemical calorie, exactly 4.184 joules, roughly the energy needed to raise one gram of water by one degree Celsius. It is used in chemistry and physics and should not be confused with the food Calorie, which is a kilocalorie.

The kilojoule (kJ) is 1,000 joules. It is used for food energy on nutrition labels in Australia, New Zealand and Europe, often next to kcal, and for reaction energies in chemistry.

See the conversion table with commonly used values, handy for quick reference or study.