1, calorie unit conversion: kcal = 1 calorie = 1 calorie = 1000 calories, 1 kilojoule = 1000 joules, 1 kilocalorie / 1 calorie / 1 calorie (kcal) = 4.184 kilojoules (kJ), 1 card = 4.182 joules.

2. 1 kcal is about = 4000 calories, 1 kcal = 4.3 calories, 1 kcal = 4.2 joules, 1 kcal = 4.184 kJ. The big card is kilocalorie, usually said that there are two kinds of card, one is thermodynamic, one is used to calculate the calorie of food, food on the big card is thermodynamic kilocalorie.