Calories to Joules

One food Calorie on a label (which is really 1 kcal) = 4,184 joules. A 100-calorie snack = 418,400 joules.

Confusion arises because food labels use kcal but write "calories" without the "kilo". Scientists prefer joules to avoid ambiguity.

Varies by activity and person. Running for 30 min might burn 300–500 food calories (1.26–2.09 million joules).