How many calories are in 1 kcal?

Answer 1

1 calorie is 4.1868 joules. This is referred to (or was when I was at school a long time ago) as the 'mechanical equivalent of heat' and is worth remembering, you can say 4.2 joules to a good approximation.

So 1 kcal = 4,186.8 joules or 4.1868 kjoules if you prefer

Answer 2

The kilo- prefix means 1000 → 1 kcal = 1000 cal

In food labelling and nutrition, the units called "calories" (as in a "calorie controlled diet") are actually kilo-calories, ie what is spoken of as 1 calorie is, in fact, actually 1 kcal.

Answer 3

1/1000