How to Calculate Serving Size for Nutrition Labels
Learn how to calculate serving size using FDA RACC tables, household measures, package rules and rounding requirements for Nutrition Facts labels.
To understand how to calculate serving size for a Nutrition Facts label, first find your product category in 21 CFR 101.12(b), identify its reference amount customarily consumed per eating occasion (RACC), then apply the conversion procedures in 21 CFR 101.9(b) to turn that reference amount into the serving size you print. It is a lookup followed by a short chain of arithmetic, not a judgment call.
What follows is the serving size calculation sequence in the order a producer encounters it, including the cases that do not fit the standard pattern. For the wider set of serving size obligations, see FDA serving size requirements. For the tables themselves and how the amounts were derived, see FDA RACC reference amounts.
Step one: find your category and reference amount
Everything that follows depends on selecting the correct row from 101.12(b). The reference amount is the amount customarily consumed per eating occasion by people 4 years of age or older.
Table 1 covers foods for infants and children 1 through 3 years of age, and 101.12(a)(2) limits those reference amounts to foods specially formulated or processed for that group. Table 2 covers everything else.
Its categories are specific. Examples include:
- Cookies: 30 g.
- Grain-based bars, including granola bars: 40 g.
- Bagels and muffins, excluding English muffins: 110 g.
- Snacks of all varieties: 30 g.
- Carbonated and noncarbonated beverages: 360 mL.
- Soups: 245 g.
Three principles in 101.12(a) can affect which reference amount you use.
First, the reference amount covers only the edible portion, not bone, seed or shell, under 101.12(a)(6).
Second, it follows the product's major intended use. That is why milk is referenced as a beverage rather than as an addition to cereal, under 101.12(a)(7).
Third, a food usually used as an ingredient but also eaten as purchased, with butter given as the example, is referenced as purchased under 101.12(a)(8).
Products not specifically listed
Most categories include a catch-all row phrased as "all others except those listed as separate categories." Check that first. Beyond those rows, 101.12 provides three general rules.
- Unprepared forms, 101.12(c). If 101.12(b) provides a reference amount for the prepared form but not the unprepared form, the reference amount for the unprepared product is the amount required to make the reference amount of the prepared product. Dry mixes, concentrates, dough, batter and fresh or frozen pasta are named examples. Footnote 2 to the tables repeats the rule. Dry soup mixes and bouillon are listed this way: the amount needed to make 245 g.
- Imitation and substitute foods, 101.12(d). The reference amount for an imitation, substitute or altered food, such as a low calorie version, is the same as the food it replaces. Making a lighter version does not give you a smaller reference amount.
- Combination products, 101.12(f). If neither form of a package containing two or more foods is listed, use the reference amount of the ingredient represented as the main ingredient plus proportioned amounts of the minor ingredients. Compatible units are added together. The regulation's example gives 4 tablespoons for equal volumes of peanut butter and jelly, 2 tbsp of each, with peanut butter as the main ingredient. Incompatible units are converted to weight first, so pancakes and syrup use 110 g for the pancakes plus the weight of the proportioned syrup.
If none of these rules reaches your product, 101.12(h) permits a petition to establish a new reference amount. In practice, the catch-all row almost always provides the answer first.
Our RACC lookup tool searches the 101.12(b) categories by product description.
How to calculate serving size for discrete units
101.9(b)(2) requires the declared serving size to be determined from the reference amounts in 101.12(b), with exceptions at 101.9(b)(3), (b)(4) and (b)(6), and for weight-control products sold only through a weight-control program.
For products in discrete units, such as muffins, sliced bread and individually packaged products inside a multiserving package, 101.9(b)(2)(i) establishes four gates based on the ratio of one unit's weight to the applicable reference amount.
| Unit weight as a share of the reference amount | Serving size, per 101.9(b)(2)(i) | Worked case |
|---|---|---|
| 50 percent or less | The number of whole units that most closely approximates the reference amount | A 13 g cookie is 43.3 percent of the 30 g amount. Two cookies is 26 g, three is 39 g, so the serving is 2 cookies (26 g) |
| More than 50 percent but less than 67 percent | The manufacturer may declare one unit or two units | A 60 g muffin is 54.5 percent of the 110 g amount, so either 1 muffin (60 g) or 2 muffins (120 g) is compliant |
| 67 percent or more but less than 200 percent | One unit. No discretion | A 45 g granola bar is 112.5 percent of the 40 g grain-based bar amount, so the serving is 1 bar (45 g) |
| At least 200 percent and up to and including 300 percent | The amount approximating the reference amount, plus a second column of amounts and percent Daily Values per individual unit | A 90 g twin bar is 225 percent of 40 g, so the serving is half a bar (45 g) with a second column for the whole bar |
Read those boundaries exactly as written because they are not symmetrical.
The first gate ends at 50 percent inclusive. The second begins above 50 percent and ends below 67 percent. The third starts at 67 percent inclusive and continues to, but does not include, 200 percent. The fourth runs from 200 percent through 300 percent inclusive.
That means a unit weighing exactly 67 percent of the reference amount is one serving, not a choice.
The dual column in the fourth gate carries the exemptions at 101.9(b)(12)(i)(A), (B) and (C). Those cover tabular and linear format products, raw fruits, vegetables and seafood with voluntary labeling, and products already carrying a second column.
How to determine serving size for large units, bulk foods and single-serving containers
Under 101.9(b)(2)(ii), large discrete units that are usually divided before eating, such as cake, pie, pizza, melon and cabbage, use the fractional slice of the ready-to-eat product that most closely approximates the reference amount.
The permitted fractions are 1/2, 1/3, 1/4, 1/5, 1/6, or smaller fractions created by dividing those fractions by 2 or 3.
When the entire package makes one large divided unit, with cake mix and pizza kit given as examples, the fraction of the package used to make the 101.12(c) reference amount may be used instead.
Under 101.9(b)(2)(iii), nondiscrete bulk products such as breakfast cereal, flour, sugar, dry mixes and concentrates use the amount in household measure that most closely approximates the reference amount. There are no percentage gates because there is no individual unit to compare with the RACC.
101.9(b)(6) determines whether an individually sold package is a single serving. A product packaged and sold individually containing less than 200 percent of the applicable reference amount must be treated as a single-serving container, with the entire contents labeled as one serving.
For example, a 20 fl oz bottle of a carbonated beverage is 600 mL using the 30 mL per fluid ounce conversion in 101.9(b)(5)(viii). That is 166.7 percent of the 360 mL reference amount, so the whole bottle is one serving.
Because it falls above 150 percent and below 200 percent, the bottle may also voluntarily carry an additional column based on the household measure closest to the reference amount, in this case 12 fl oz.
Serving size calculation: household measure and metric equivalent
101.9(b)(5) defines common household measure as cup, tablespoon, teaspoon, piece, slice, fraction, ounce, fluid ounce, or other household equipment used to package food, such as a jar or tray.
It then establishes a hierarchy.
Use cups, tablespoons or teaspoons wherever possible and appropriate, except that beverages may use fluid ounces. If those measures do not work, use units such as piece, slice, tray, jar or fraction. If those do not work, use ounces with a visual unit of measure in 0.5 oz increments. The regulation's example is "1 oz (28 g/about 1/2 pickle)".
The permitted increments are fixed:
- Cups: 1/4 or 1/3 cup increments.
- Tablespoons: 1, 1 1/3, 1 1/2, 1 2/3, 2, or 3.
- Teaspoons: 1/8, 1/4, 1/2, 3/4, 1, or 2.
The conversions in 101.9(b)(5)(viii) are also fixed:
- 1 teaspoon is 5 mL.
- 1 tablespoon is 15 mL.
- 1 cup is 240 mL.
- 1 fl oz is 30 mL.
- 1 oz by weight is 28 g.
Use these regulatory conversions rather than exact physical conversions, or your gram figures can drift from a reviewer's calculation.
Consider a worked bulk example. A ready-to-eat cereal weighing 30 g per cup falls within the category for cereals weighing 20 g or more but less than 43 g per cup, which has a 40 g reference amount.
Divide 40 g by 30 g per cup and you get 1.333 cups. One third is a permitted increment, so the serving size is 1 1/3 cups (40 g).
If the arithmetic lands exactly between two permitted serving sizes, 101.9(b)(5)(ix) requires rounding up to the next incremental size. The regulation's example is 2.5 tbsp becoming 3 tablespoons.
The metric equivalent appears in parentheses under 101.9(b)(7), with fluids stated in milliliters and everything else in grams.
Rounding under 101.9(b)(7)(ii) is to the nearest whole number, except that a quantity between 2 and 5 g or mL rounds to the nearest 0.5, while a quantity below 2 g or mL is expressed in 0.1 increments.
A single-serving container does not need the parenthetical metric quantity because it already appears in the net quantity of contents statement required by 21 CFR 101.7. If you provide it voluntarily, 101.9(b)(7)(i) requires it to match that declaration exactly.
Servings per container and rounding under 101.9(b)(8)
101.9(b)(8) calculates servings per container from the serving size you just determined, not directly from the reference amount.
Its rounding rules have one break point. Round to the nearest whole number, except that a result between 2 and 5 servings rounds to the nearest 0.5 serving. Random weight products are excluded.
When rounding occurs, use the word "about".
| Package | Serving size | Raw division | Declared |
|---|---|---|---|
| 99 g bag of chips | 1 oz (28 g) | 3.54 | about 3.5 servings |
| 170 g bag of chips | 1 oz (28 g) | 6.07 | about 6 servings |
| 350 g box of cereal | 1 1/3 cups (40 g) | 8.75 | about 9 servings |
| 16 cookies at 13 g | 2 cookies (26 g) | 8.00 | 8 servings, with no "about" |
The last row is important. "about" tells the reader that rounding occurred. If the division produces an exact result, leave it off.
Two multipack rules also apply.
Under 101.9(b)(8)(iv), if a package contains several individual single-serving containers that are each labeled for individual sale, the number of servings is the number of packages inside. Each individual unit is itself one serving under 101.9(b)(2)(i)(H).
Under 101.9(b)(8)(v), when a package contains several individually packaged multiserving units, multiply the number of units by the number of servings in each.
Aggregate packages and variable-weight products
Variety packs and compartment trays. Under 101.9(b)(4), a variety pack containing several single-serving varieties, or a product with two or more compartments each containing a different food, must provide nutrition information for each variety. Each serving size is derived from that variety's own 101.12(b) reference amount. The rule does not call for one averaged panel across all varieties.
Meal and main dish products. Under 101.9(b)(3), meal and main dish products defined in 101.13(l) and (m) are declared, when sold as single-serving containers, as the entire contents of the package, edible portion only. In multiserving containers, they use the 101.12(b) reference amount if listed, or the 101.12(f) combination rules if not.
Components eaten together. Under 101.9(b)(5)(vii), nutrition information may be declared per component or as a composite. Serving size may follow the discrete, divided or bulk procedures, or it may be stated in ounces with a visual unit of measure, as in "3 oz dry macaroni (84 g/about 2/3 cup)" plus "1 oz dry cheese mix (28 g/about 2 tbsp)".
Products that naturally vary in size. Under 101.9(b)(2)(i)(F), pickles, shellfish, whole fish and fillet of fish may be declared in ounces closest to the reference amount, using 0.5 oz increments with a visual unit of measure under 101.9(b)(5)(vi) and (b)(5)(iii).
Pickles have a 30 g reference amount and a label statement of "1 oz (28 g/visual unit of measure)". Because they are packed in a liquid not customarily consumed, 101.9(b)(9) bases the declaration on the drained solids.
When serving size is based on drained solids and the number of servings varies according to unit size, 101.9(b)(8)(ii) permits a typical number, such as "usually 5 servings".
Random weight products. Under 101.9(b)(8)(iii), foods such as cheeses sold at random weights, where net contents vary from container to container, may declare "varied" for servings per container. Nutrition information must still be based on the reference amount in the appropriate household measure from the 101.9(b)(5) hierarchy.
Cheese other than the separately listed types has a 30 g reference amount. The typical number of servings may be included in parentheses.
One rule holds across all of these situations. Under 101.12(g), the reference amount, not your declared serving size, determines whether the product qualifies for a nutrient content or health claim.
When the reference amount and declared serving size differ, the claim must state the basis, for example "Very low sodium, 35 mg or less per 240 mL (8 fl oz)".
Once you have established the reference amount, unit ratio and household measure, the nutrition label generator applies the gates and all three rounding rules and builds the Nutrition Facts panel from those inputs.
How to calculate serving size: frequently asked questions
Can I choose my own serving size to make the numbers look better?
No. 101.9(b)(2) requires serving size to be determined from the reference amounts in 101.12(b). The main discretion is the second gate, where a unit weighing more than 50 percent but less than 67 percent of the reference amount may be declared as one or two units. A narrow exception applies to qualifying weight-control products sold only through a weight-control program.
My product category is not in the tables. How do I determine serving size?
Start with the catch-all row in the closest category, usually phrased as all others except those listed separately. Unprepared forms use 101.12(c), substitutes use 101.12(d), and foods packaged together use 101.12(f). Only when those rules do not provide an answer does a petition under 101.12(h) come into play.
When do I have to print two columns?
Three situations in 101.9(b) can require them. A discrete unit at 200 to 300 percent of the reference amount requires a per-unit column under 101.9(b)(2)(i)(D). An individually sold product at 200 to 300 percent requires a whole-package column under 101.9(b)(12)(i), subject to its exemptions. A promoted use differing by twofold or more can also trigger a column under 101.9(b)(11), subject to its exemptions.
Does the whole bottle count as one serving?
Yes, if it is packaged and sold individually and contains less than 200 percent of the applicable reference amount. Under 101.9(b)(6), the entire package is then one serving. A 600 mL carbonated beverage is 166.7 percent of the 360 mL reference amount, so the whole bottle is one serving. At 200 percent or more, dual-column rules begin to apply.
Do infant and toddler products use different reference amounts?
Only when the food qualifies. Under 101.12(a)(2), reference amounts for infants up to 12 months and children 1 through 3 years apply only to foods specially formulated or processed for those groups. Those amounts appear in Table 1 of 101.12(b). A general-market food that toddlers happen to eat continues to use the Table 2 reference amounts.
