Calories (cal) to kilojoules (kJ), energy conversion calculator and how to convert.

## Calories to kilojoules conversion calculator

Select calorie unit type, enter the energy in calories and press the *Convert* button:

## 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 calories *E*_{(calth}) divided by 239.005736:

*E*_{(kJ)} = * E*_{(calth)} / 239.005736

#### Example

Convert 300 cal_{th} to kilojoules.

*E*_{(kJ)} = 300cal_{th} / 239.005736 = 1.2552 kJ

### 15°C calories to kJ

1 cal_{15} = 0.0041855 kJ

1 kJ = 238.9201 cal_{15}

The energy in kilojoules *E*_{(kJ)} is equal to the energy in 15°C calories *E*_{(cal15)} divided by 238.9201:

*E*_{(kJ)} = * E*_{(cal15)} / 238.9201

#### Example

Convert 300 cal_{15} to kilojoules.

*E*_{(kJ)} = 300cal_{15} / 238.9201 = 1.25565 kJ

### Large/food calories to kJ

1 Cal = 4.184 kJ

1 kJ = 0.239 Cal

The energy in kilojoules *E*_{(kJ)} is equal to 4184 times the energy in large/food calories *E*_{(Cal)}:

*E*_{(kJ)} = 4.184* × E*_{(calth)}

#### Example

Convert 0.3 Cal to kilojoules.

*E*_{(kJ)} = 4.184 *× *0.3 Cal = 1.2552 kJ