Three ways labels count
| Label basis | Where you see it | How to read it |
|---|---|---|
| Per serving | US Nutrition Facts; many multi-serving packs | Multiply by servings eaten — check "servings per container" |
| Per package (or dual column) | Single-serve packs; US dual-column labels show one serving and the whole package | Ate it all? Use the package column |
| Per 100 g (ml) | EU-style labels; large packs | Grams eaten ÷ 100 × label kcal |
The FDA points out that the serving size is not a recommendation of how much to eat, and that one package may hold more than one serving. Korea, as another example, switched in 2016 to labeling most packs per total contents, with per-unit labels for items split into pieces and per-100 g for large packs.
Converting to what you ate
- A 300 g bag of chips at 450 kcal per 100 g, half the bag → 150 ÷ 100 × 450 = 675 kcal
- "120 kcal per cookie (25 g), 8 per pack", three cookies → 120 × 3 = 360 kcal
- A 1.5 L drink at 40 kcal per 100 ml, one 250 ml glass → 2.5 × 40 = 100 kcal
Per-100 g numbers are great for comparing products but easy to mis-log, because nobody eats exactly 100 g.
What else to check
- Sugars and sodium — two products with equal calories can differ a lot here.
- % Daily Value — based on a reference diet, not your own calorie target.
- As sold vs prepared — for products you cook, check which one the label describes.
Logging it in the app
Enter the converted number
On the Diet tab in Calorie Calculator, put the amount in the food name, such as "chips, half bag", and enter the calories you worked out. Keeping the amount in the name avoids confusion later.
Favorite your fixed snacks
Products you always have in the same amount, like a daily drink, can be saved as a favorite and added in one tap.
Sample food names in the screenshots are in Korean; the app itself runs in English.
FAQ
What about food with no label?
Restaurant and home-cooked food usually has none. See estimating calories without a label.
Is a "0 calorie" drink really zero?
Labeling rules let very small amounts round down to zero. A glass or two is negligible.
Sources: FDA, Serving Size on the Nutrition Facts Label
Calorie Calculator: BMR TDEE
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