Calories to Kilojoules (kJ) conversion

Small & large calories

Small calorie (cal) is the energy needed to increase 1 gram of water by 1°C at a pressure of 1 atmosphere.

Large calorie (Cal) is the energy needed to increase 1 kg of water by 1°C at a pressure of 1 atmosphere.

Large calorie is also called food calorie and is used as a unit of food energy.

How to convert from calories to kilojoules

Thermochemical calories to kJ

1 cal_th = 0.004184 kJ

1 kJ = 239.005736 cal_th

The energy in kilojoules E_(kJ) is equal to the energy in thermochemical caloriesE_(calth) divided by 239.005736:

E_(kJ) = E_(calth) / 239.005736

kJ to calories conversion