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

## 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 joules to calories

### Joules to thermochemical calories

1 cal_{th} = 4.184 J

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

*E*_{(cal)} = *E*_{(J)} / 4.184

#### Example

Convert 600 joules to thermochemical calories.

*E*_{(cal)} = 600J / 4.184 = 143.4 cal_{th}

### Joules to 15°C calories

1 cal_{15} = 4.1855 J

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

*E*_{(cal15)} = *E*_{(J)} / 4.1855

#### Example

Convert 600 joules to 15°C calories.

*E*_{(cal15)} = 600J / 4.1855 = 143.352 cal_{15}

### Joules to large/food calories

1 Cal = 4.184 kJ = 4184 J

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

*E*_{(Cal)} = *E*_{(J)} / 4184

#### Example

Convert 600 joules to food calories.

*E*_{(Cal)} = 600J / 4184 = 0.1434 Cal

Joules to calories conversion calculator ►