How to Read a Nutrition Facts Label (and What USDA Numbers Actually Mean)

A Nutrition Facts label lists a food's calories and nutrients for one labeled serving, plus a %Daily Value showing how much each contributes to a 2,000-calorie reference diet. USDA databases like FoodData Central, which power this site, report the same nutrients per 100 grams instead — so raw numbers won't match the label unless you convert first.

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What does each line on a Nutrition Facts label actually tell you?

Every US Nutrition Facts label follows the same fixed order, and each line answers a specific question rather than just stating a number. The top block states servings per container and serving size — every single number printed below it describes one of those servings, not the whole package, which matters most for anything sold as a multi-serving container (a pint of yogurt, a bag of chips, a two-portion frozen entrée). Below that, Calories measures the energy in one serving, printed in large type because it's the figure most people scan first. Then comes the nutrient block itself, split into two implicit groups: fats, cholesterol, sodium, carbohydrate and protein by weight come first, followed by vitamins and minerals, each with its own %Daily Value column on the right-hand side. According to the U.S. Food and Drug Administration's guide to understanding the Nutrition Facts label, that layout is deliberate, not arbitrary: nutrients Americans typically over-consume (saturated fat, sodium, added sugars) are grouped together near the top of the nutrient block, and nutrients Americans typically under-consume (dietary fiber, vitamin D, calcium, iron, potassium) are grouped lower down, closer to the footnote. Reading the label top to bottom in its printed order walks you through the FDA's own priority list, not just a column of numbers in no particular sequence.

What does %Daily Value mean — and is 5% or 20% good or bad?

The %Daily Value (%DV) column translates an absolute amount (36mg of sodium, say) into a share of a reference daily target, so you can judge a number without memorizing targets for 20 different nutrients. The FDA's own rule of thumb, stated directly on its guidance on interpreting %Daily Value, is: "5% DV or less of a nutrient per serving is considered low" and "20% DV or more of a nutrient per serving is considered high." Those percentages are calculated against a 2,000-calorie-a-day reference diet, which the FDA is explicit is "used for general nutrition advice" rather than a personal calorie target — someone eating 1,600 or 2,400 calories a day will hit a different actual share. The Daily Value figures themselves — 2,300mg for sodium, 1,300mg for calcium, 20mcg for vitamin D, 4,700mg for potassium — come from the FDA's own reference table, published per the FDA's Daily Value explainer and the labeling regulation at 21 CFR 101.9. (A separate guide on this site, RDA vs. Daily Value, goes into why those label figures are single flat numbers rather than the age- and sex-specific figures nutrition science actually uses.)

Which nutrients should you limit, and which should you get more of?

The FDA's guidance groups the label's nutrients into two practical buckets. Limit: saturated fat, sodium, and added sugars — all three are linked to cardiovascular risk and are, per the FDA, consumed in excess by most Americans relative to the reference amounts. Get more of: dietary fiber, vitamin D, calcium, iron, and potassium — nutrients most Americans' diets fall short on. This isn't a judgment about any single food; a food can be high in saturated fat and high in potassium at the same time, and the label doesn't average those into one verdict. It just reports each nutrient on its own line, and it's on the reader to weigh the pattern across their whole day, not one label in isolation.

How should you use the label when comparing two products?

The label's per-serving format only works for a fair comparison if the two products share the same serving size — and that's frequently not the case. Two brands of bread, two yogurts, or two breakfast cereals can each define "one serving" differently based on their own package size and the FDA's reference amount for that food category, so a side-by-side read of two labels' raw grams, calories, or %DV can quietly compare unequal portions. This is exactly the problem USDA's own reference data sidesteps by standardizing everything to 100 grams: a database entry for whole-wheat bread and one for white bread both report their numbers against the same 100g baseline, so the figures are comparable without any extra math, even though the labels on the two loaves might use different per-slice serving sizes. When comparing packaged products at the store, check that the serving sizes actually match before trusting a direct number comparison; when comparing USDA database entries on a site like this one, that step is already handled for you.

Why don't the USDA numbers on this site match the label on my package?

This is the single most common point of confusion between a grocery-store label and a USDA reference database, and it comes down to a basic unit mismatch. The Nutrition Facts label reports nutrients per labeled serving — a size the manufacturer sets based on how much people actually eat in one sitting. USDA's FoodData Central, and every food and ingredient page on this site, instead reports nutrients per 100 grams of the item, full stop, regardless of how anyone portions it. Take plain nonfat Greek yogurt in this database: per 100g it measures 61 kcal, 10.3g protein, and 111mg calcium. A single 156-gram container of that same yogurt — a real portion size recorded against this exact food record — works out to roughly 95 kcal, 16g protein, and 173mg calcium, none of which is the number a shopper would see if they only looked up the 100g figure and assumed it was "the serving." Comparing a 100g database value directly to a label's per-serving line without scaling is the most common way this site's numbers get misread. The same arithmetic applies to any food with a recorded portion weight in this database — a 100g value for commercially prepared whole-wheat bread (254 kcal, 43.1g carbohydrate, 450mg sodium) scales down to roughly 82 kcal, 14g carbohydrate, and 144mg sodium for one recorded 32.1-gram slice — again, a hand calculation from the database's own per-100g figure and its own recorded portion weight, not an outside estimate. (The companion guide Understanding Per-100g vs. Per-Serving Nutrition Data walks through that conversion in full, including why most FNDDS ingredient entries on this site don't have a portion weight to convert with at all.)

Does USDA's data even track everything the label shows?

Not always, and this is worth knowing before you go looking for a number that isn't there. Added Sugars has had its own mandatory line on US Nutrition Facts labels since 2020, and FoodData Central does carry a corresponding nutrient row for it ("Sugars, added," nutrient number 539). But a direct query against this database's full nutrient-value tables — covering all 1,882 FNDDS survey ingredients and the 469 Foundation/SR Legacy foods tracked here — returns zero populated added-sugars values across either set. That's not a bug specific to one food's page; it's a gap in what USDA's underlying survey and reference datasets currently carry for added sugars at the ingredient level, something no single nutrient or food page states on its own because each one only describes its own, individually-empty cell. If a label in front of you lists an added-sugars gram amount, that number came from the manufacturer's own formulation data submitted for labeling purposes — not from the USDA survey data this site is built on, which only goes back to total sugars.

A 30-second checklist for reading any label

In order: check servings per container first, so you know whether the numbers below describe your actual portion or a fraction of the package. Read calories for one serving, and remember that figure is based on the FDA's 2,000-calorie reference diet only for the %DV column, not for the calorie count itself. Scan the %DV column for anything at 20% or higher in saturated fat, sodium, or added sugars — that's worth noticing before you eat it, not after. Scan the same column for dietary fiber, vitamin D, calcium, iron, and potassium — those are the ones worth seeking a higher %DV on, per the FDA's own under-consumption list. Before comparing two packaged products side by side, confirm their serving sizes actually match; if they don't, the raw numbers aren't a fair comparison no matter how close together the packages sit on a shelf. And if you're cross-referencing a USDA number from a site like this one against the label in your hand, confirm you're comparing the same base amount — 100 grams here, one labeled serving on the box — before concluding the numbers disagree.

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