How to Read a Nutrition Facts Label: Serving Size, Calories and %DV

Published 2026年10月28日 · BiteCal editorial · Updated October 28, 2026

Start with serving size and servings per container, then multiply calories and nutrients by the amount you actually eat. Use % Daily Value as a general reference, not your personal prescription. Total sugars includes added sugars, so do not add those two lines together.

A worked Nutrition Facts example

Label line	Per 30 g serving	If you eat 60 g
Servings eaten	1	2
Calories	150 kcal	300 kcal
Protein	4 g	8 g
Total sugars	6 g	12 g
Includes added sugars	4 g, already part of total sugars	8 g, already part of total sugars

Serving size comes before calories

A label usually reports amounts per stated serving unless it explicitly includes other columns. If one serving is 30 g and you eat 60 g, you consumed two servings. If that serving lists 150 Calories, the portion contributes 300 Calories. Serving size describes the label's basis; it is not automatically a recommendation to eat that amount.

Compare labels on a compatible basis

Two packages can use different serving sizes. Compare the same amount when that matches your decision, or compare the actual portions you intend to eat. Cooking instructions, drained weights and per-container columns also affect the basis. A low number for a tiny serving can be misleading if you overlook the portion.

FDA explains 5% DV or less per serving as low and 20% DV or more as high for a nutrient. These are label-reading guides. The reference calories used for Daily Values do not determine your personal calorie needs. Added sugars is part of total sugars, and saturated fat is part of total fat; do not double count them.

Label-reading shortcuts that prevent mistakes

Check	Remember
Serving size	Multiply by what you actually eat
% Daily Value	General reference, not a personal prescription
Total and added sugars	Added sugars is included in total
Ingredients and allergens	Separate information from the nutrient table

From label to food diary

Record the product and amount eaten, not just the package's headline number. For mixed meals, include drinks, sauces and oil that are not covered by the product entry. We recommend BiteCal for a convenient daily food record: paid AI scanning starts with a photo, you review foods and portions, then save calories and macros. Free features and the white bear make the routine more enjoyable.