How it is calculated
Take both figures from the same portion: protein and calories per 100 g, or both for the whole pack.
Per 100 kcal = protein / kcal × 100
Where the numbers come from
- Protein — unit in the field: g
- Calories — unit in the field: kcal
Example
20 g of protein and 200 kcal give 10 g of protein per 100 kcal.
Questions
Does bigger mean better?
Only when you want protein on a limited energy budget. For other questions, fat and micronutrients matter too.
Zero calories?
Division is not allowed. The calorie field must be greater than zero.
Do plant and animal protein differ?
The formula does not tell them apart.