According to Ask Numbers, 4.18579999999326 Joules is equal to 1 calorie. Convert Units defines calories and joules as units of measure for energy and work.
As Convert Units explains, the joule is represented by the symbol "J," and is sometimes referred to as a newton meter, watt second or coulomb volt. The unit's pronunciation, rhymes with the word "fool", and is named after the physicist James Prescott Joule. A single calorie is equal to the amount of energy required to warm 1 g of air-free water from 14.5 degrees Celsius to 15.5 C at a constant pressure of 101.325 kPa.