Calories (cal) to joules (J), energy conversion calculator and how to convert.
Calories to joules conversion calculator
Select calorie unit type, enter the energy in calories and press the Convert button:
Joules to calories conversion ►
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
Joules to calories conversion ►