how many kj in a calorie

One calorie (technically, one kilocalorie used in food energy) is equal to 4.18 kilojoules (kJ). For rough conversions, it is often rounded to 4 kJ per calorie for simplicity, but the exact value is 4.18 kJ. This means to convert calories to kilojoules, multiply the number of calories by 4.18. Conversely, to convert kilojoules to calories, divide the kilojoules by 4.18.