How to convert calories to joules

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 calth = 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 calth to joules.

E(J) = 4.184 × 300calth = 1255.2 J

15°C calories to joules

1 cal15 = 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 cal15 to joules.

E(J) = 4.1855 × 300cal15 = 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 ►

 


See also

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