How to convert energy in calories (cal) to joules (J).

## 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 joules

### Thermochemical calories to joules

1 cal_{th} = 4.184 J

The energy in joules *E*_{(J)} is equal to 4.184 times the energy in thermochemical calories *E*_{(calth)}:

*E*_{(J)} = 4.184* × E*_{(calth)}

#### Example

Convert 300 cal_{th} to joules.

*E*_{(J)} = 4.184 *× *300cal_{th} = 1255.2 J

### 15°C calories to joules

1 cal_{15} = 4.1855 J

The energy in joules *E*_{(J)} is equal to 4.1855 times the energy in 15°C calories *E*_{(cal15)}:

*E*_{(J)} = 4.1855* × E*_{(cal15)}

#### Example

Convert 300 cal_{15} to joules.

*E*_{(J)} = 4.1855 *× *300cal_{15} = 1255.65 J

### Large/food calories to joules

1 Cal = 4.184 kJ = 4184 J

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

*E*_{(J)} = 4184* × E*_{(Cal)}

#### Example

Convert 0.3 Cal to joules.

*E*_{(J)} = 4184 *× *0.3 Cal = 1255.2 J

Calories to joules conversion calculator ►