Fair comparisons start with a clear basis.

Weight, volume, and portions

USDA reference-food composition is recorded per 100 grams. Branded records can use a 100-gram or 100-millilitre basis, depending on the submitted source unit. We preserve that distinction. We do not assume a millilitre weighs one gram.

A portion calculator multiplies a reported nutrient amount by the chosen amount divided by 100. Source portion weights are used when supplied. A source serving is a recorded portion, not a recommended amount to eat.

For a weight-based food, a nutrient reported as 10 g per 100 g becomes 17 g in a 170 g portion. The calculation changes quantity, not the food’s composition.

Four comparison choices

• 100 g or 100 ml: a consistent source-unit comparison. This option is unavailable across a weight-based and a volume-based record.
• Source serving: each food’s recorded portion. Portions may have different weights or volumes.
• Equal calories: amount = target calories × 100 ÷ calories per 100 source units.
• Equal protein: amount = target protein × 100 ÷ protein per 100 source units.

Equal-calorie and equal-protein comparisons require a reported, positive denominator for each food. When the necessary value is missing or zero, that basis is unavailable.

Missing is different from zero

A dash means no value was reported or no applicable daily value is shown. We do not fill a missing nutrient with zero, infer it from another food, or complete branded micronutrients from a generic food.

A reported zero is retained. On a manufacturer label, rounding can produce zero even when laboratory analysis would find a small amount. “Not a significant source of” is not converted to a numerical zero.

Rankings and alternative choices

Rankings use a reported nutrient, a selected comparison basis, and explicit user constraints. A constraint excludes a record when the nutrient needed to check it is missing. General rankings exclude drinks, oils and seasonings, and unclassified records; a category selection can include them.

Per-100-gram rankings use weight records. Equal-calorie and source-serving rankings can include weight and volume records, with the amount and original unit shown for each food. Rankings require at least 20 reported calories per 100 source units to avoid density calculations dominated by tiny energy values. Milk and drink categories open on an equal-calorie basis.

Alternative choices stay in the same broad category and source family. They must have a better reported value on the chosen basis. A nutritional alternative may differ in preparation, ingredients, taste, or intended use; it is not an automatic equivalent in a recipe.

Titles such as “high protein” and “low sodium” describe the search task and comparative ordering. The site does not certify that a product meets a regulated nutrient-content claim.

Product identifiers and history

We validate supported GTIN check digits and normalize the identifier to 14 digits. US records sharing that identifier are grouped, with the latest modified date, then publication date and source ID, selecting the displayed record. Invalid or absent identifiers remain separate.

A barcode match is evidence that records share an identifier, not proof of continuous retail availability or identical formulation. Historical nutrient changes may be corrections. Check the original record before treating a unit change as a composition change.

When same-brand records have an identical name, ingredient list, nutrient vector, and serving, one qualifying profile can represent that data in the indexing set. Other barcodes stay searchable and point to that primary profile while it meets the discovery criteria.

Overlapping USDA reference records can describe the same named food and preparation while reporting different values. We select a primary reference, preferring Foundation data when available, and keep other source records accessible with a link to the primary profile. Their original nutrient values stay intact.

Which profiles qualify for discovery pages?

Complete profiles need reported calories, protein, carbohydrate, and fat, an informative name, and plausible source amounts. Branded profiles additionally need a validated barcode, a brand or manufacturer, a supported weight or volume basis, at least two of fiber, sugar and sodium, and a label modified on or after 1 January 2024. Records marked discontinued are excluded from discovery rankings. We also exclude records when the source quantity disagrees by more than 5% with a single explicit amount in the same unit, or when the source serving and household text use different units without a verifiable relationship. Preparation instructions for reconstituted foods are treated separately.

Discovery profiles also need a distinct food identity. If multiple branded records share an indistinguishable supplied name, we exclude them instead of guessing the flavor or variant. Readable titles preserve source preparation and distinguishing product details; the full original description stays on the page.

Excluded records can remain available for reference through search, with a visible notice and an instruction to search engines not to index them. Reference-food age is disclosed separately because the final SR Legacy release is historical composition data.

Brand directories need at least six qualifying profiles. Category-specific ranking pages need at least six qualifying choices. These gates describe source completeness; they do not prove current product availability.

Daily values and energy estimates

Displayed daily values use the FDA adult reference values. They are a general label-reading reference. We do not show a percent daily value for total sugars or an uncorrected protein amount.

The macro visualization estimates energy using 4 kcal per gram of protein and carbohydrate and 9 kcal per gram of fat. It is shown only with all three reported macros. Fiber, alcohol, other components, and rounding can make this estimate differ from the reported calorie value.

Limitations and corrections

Records may contain source errors, outdated labels, or classification errors. The archive is not a complete inventory of foods sold today. Ingredients do not establish allergen safety, and food composition does not establish suitability for an individual medical condition.

See data sources and dates for snapshot provenance. Report a suspected error through contact and corrections.