Kilojoules to Calories Converter

To convert a measurement in kilojoules to calories, multiply the value by 239.005736. The conversion factor comes from the relationship between both units and the joule.

For example, to convert 5 kJ to calories: 5 × 239.005736 = 1,195.0287 cal.

A kilojoule equals 1,000 joules and is the standard metric unit for expressing food energy on nutrition labels in most of the world. As metric countries adopted SI units for food labeling, the kilojoule replaced the food calorie on packaging in regions such as Australia, New Zealand, and the European Union (shown alongside kcal).

Common uses of kilojoules include: Food energy on nutrition labels; Dietary and exercise energy tracking; Chemical reaction energy (enthalpy); Battery and mechanical energy specs.

A calorie (small calorie) is the energy needed to raise the temperature of one gram of water by one degree Celsius, defined as exactly 4.184 joules. The calorie originated in early-19th-century thermodynamics. The thermochemical calorie, fixed at exactly 4.184 J, is the modern standard, though it is often confused with the larger food Calorie (kilocalorie).

Common uses of calories include: Chemistry and thermodynamics; Heat-of-reaction measurements; Physics heat-transfer problems; Historical energy references.

Here are some common values converted:

1 kJ = 239.005736 cal 5 kJ = 1,195.0287 cal 10 kJ = 2,390.0574 cal 50 kJ = 11,950.2868 cal 100 kJ = 23,900.5736 cal