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.

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)

Convert 300 cal_th to joules.

E_(J) = 4.184 × 300cal_th = 1255.2 J

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)

Convert 300 cal₁₅ to joules.

E_(J) = 4.1855 × 300cal₁₅ = 1255.65 J

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)

Convert 0.3 Cal to joules.

E_(J) = 4184 × 0.3 Cal = 1255.2 J