1 kcal/1 kcal/1 kcal = 4.184 kJ.

1 card = 4.182 joules.

Generally speaking, calories in extended materials can be divided into two types:

The calorie, also known as the capital letter C, is most commonly used in food labeling, which is equivalent to the heat required to raise 1000 grams of water from 1 4.5℃ to 15.5℃ at1atmospheric pressure, which is about equal to the internal energy of 4 186 joules.

Small card, also known as cal, is more common in scientific research documents. 1000 small card = 1 big card.

reference data

Calories _ Baidu Encyclopedia