Guide
Serving sizes: why two labels of the same food differ
A serving size is the amount the label describes, set by FDA's reference amounts for each kind of food since the 2016 rule; within one kind, packages still use different sizes, so compare per 100 g when the servings differ.
Published · By GetFoodFacts · the rules are cited to FDA and USDA, the figures computed from USDA FoodData Central (April 30, 2026 release)
Where the number comes from
FDA publishes a reference amount customarily consumed (RACC) for each kind of food, 21 CFR 101.12: 30 g for chips, 2/3 cup for ice cream, 170 g for yogurt. The label's serving is the household measure closest to it, and a package holding less than twice the reference amount is labeled as one serving (21 CFR 101.9(b)(6)). The 2016 rule raised several amounts (ice cream from 1/2 to 2/3 cup, soda to 12 fl oz) to match what people eat, and records submitted before it keep their older sizes.
The spread in six aisles
| Aisle | Products | Serving sizes | Low (10th percentile) | High (90th percentile) | Most common |
|---|---|---|---|---|---|
| Ice cream | 10,919 | 230 | 64 | 118 | 65 (6%) |
| Bread | 9,097 | 180 | 28 | 85 | 57 (12%) |
| Chips | 7,416 | 90 | 28 | 30 | 28 (84%) |
| Cereal | 7,146 | 124 | 28 | 60 | 40 (13%) |
| Soda | 6,635 | 108 | 240 | 360 | 355 (38%) |
| Yogurt | 5,381 | 114 | 113 | 225 | 150 (36%) |
Source: USDA FoodData Central branded foods, April 30, 2026 release; grams or milliliters as declared.
Comparing fairly
Per serving tells you what one portion of that package gives. Per 100 g tells you which food is richer or leaner, whatever the portion. Every GetFoodFacts product page shows both, and the aisle rankings rank per 100 g for that reason.
Serving sizes in every aisle (research)
Sources for this page
- USDA FoodData Central
- the food and product records, April 30, 2026 release. fdc.nal.usda.gov
- USDA Food and Nutrient Database for Dietary Studies
- the survey foods and their portions. ars.usda.gov
- 21 CFR 101.9, Nutrition labeling of food
- the label format, rounding and Daily Values. ecfr.gov
- 21 CFR 101.12, Reference amounts customarily consumed
- the serving each kind of food is labeled by. ecfr.gov
- FDA, Daily Value on the Nutrition and Supplement Facts Labels
- the Daily Values in a table. fda.gov