Nutrition Label Portion Calculator
Enter your portion and the label lines for 1 serving. A 1.5-cup portion of a 280-calorie food has 420 kcal and 1,275 mg of sodium.
Last reviewed
Nutrition in your portion
Servings eaten
1.5 servings
Calories
420 kcal
Sodium
1,275 mg
A portion of 1.5 against a serving size of 1 is 1.5 servings and has 420 kcal (420 kcal on a rounded label).
It supplies 22.5 g protein, 51 g carbs, and 13.5 g fat (6.8 g saturated fat, or 33.8% DV).
Sodium is 1,275 mg (55.4% of the 2,300 mg Daily Value, or 1,280 mg rounded).
The 4-4-9 macro check gives 416 kcal.
Your portion and label values
- Servings eaten = 1.5 ÷ 1 = 1.5 servings
- Sodium in portion = 850 mg × 1.5 = 1,275 mg (label 1,280 mg)
- Sodium %DV = 1,275 mg ÷ 2,300 mg × 100 ≈ 55.4%
- Calories = 280 kcal × 1.5 = 420 kcal
Share of the Daily Value in the portion eaten
Calories across serving multiples (exact vs. FDA label-rounded)
Share of the FDA Daily Value in your portion (21 CFR 101.9(c)(9))
| Nutrient | In the portion | As a label may show it | FDA Daily Value | Exact %DV (%) | Label %DV (%) | FDA 5% / 20% guide (on label %DV) |
|---|---|---|---|---|---|---|
| Total fat | 13.5 g | 14 g | 78 g | 17.3 | 17 | Between low and high |
| Saturated fat | 6.8 g | 7 g | 20 g | 33.8 | 34 | High |
| Sodium | 1,275 mg | 1,280 mg | 2,300 mg | 55.4 | 55 | High |
| Total carbohydrate | 51 g | 51 g | 275 g | 18.5 | 19 | Between low and high |
| Dietary fiber | 6 g | 6 g | 28 g | 21.4 | 21 | High |
| Added sugars | 0 g | 0 g (may be zero) | 50 g | 0.0 | 0 | Low |
| Protein | 22.5 g | 23 g | 50 g | 45.0 | 45 | High |
For 1.5 servings, sodium reaches 1,275 mg (55.4% exact DV), saturated fat reaches 33.8% DV, and protein reaches 45.0% DV against a 2,000-calorie reference diet; the Label %DV column rounds each share to a whole integer under 21 CFR 101.9(d)(7)(ii).
Portion scaling comparison (exact vs. 21 CFR 101.9(c) label-rounded)
| Portion | Servings | Exact kcal | Label kcal | Protein (g) | Carbs (g) | Fat (g) | Sodium (mg) | Sodium %DV (%) |
|---|---|---|---|---|---|---|---|---|
| 0.5 (0.5 srv) | 0.5 | 140 | 140 | 7.5 | 17.0 | 4.5 | 425 | 18.5 |
| 1 (1 srv) | 1 | 280 | 280 | 15.0 | 34.0 | 9.0 | 850 | 37.0 |
| 1.5 (1.5 srv) | 1.5 | 420 | 420 | 22.5 | 51.0 | 13.5 | 1,275 | 55.4 |
| 2 (2 srv) | 2 | 560 | 560 | 30.0 | 68.0 | 18.0 | 1,700 | 73.9 |
| 3 (3 srv) | 3 | 840 | 840 | 45.0 | 102.0 | 27.0 | 2,550 | 110.9 |
| 4 (4 srv) | 4 | 1,120 | 1,120 | 60.0 | 136.0 | 36.0 | 3,400 | 147.8 |
At 1.5 servings, exact linear scaling yields 420 kcal and 1,275 mg sodium, compared with 420 kcal and 1,280 mg when rounded independently under 21 CFR 101.9(c)(1) and (c)(4).
How portion scaling and FDA Nutrition Facts math work
Every number on a US Nutrition Facts panel is for 1 serving, not the whole box or can. Eating more or less scales every line at the same rate. First, divide the amount you ate by the label serving size. Next, multiply each per-serving line by that serving count. Use the same unit for both numbers, such as cups, pieces, or grams.
When you pick the whole package mode, the multiplier is the label's servings per container. Under 21 CFR 101.9(b)(8)(i), labels round servings per container to the nearest whole number above 5 servings. Between 2 and 5 servings, they round to the nearest 0.5 serving and prefix the count with about (such as about 3.5 servings). To scale a full home batch, use the recipe scaler.
The Daily Value table checks your portion against 21 CFR 101.9(c)(8)(iv) and 101.9(c)(9) for ages 4 and older. On a 2,000 kcal diet, daily limits are 78 g fat, 20 g saturated fat, and 2,300 mg sodium. Carb targets are 275 g carbs, 28 g fiber, 50 g added sugars, plus 50 g protein. Check single lines in the Daily Value tool.
How FDA serving sizes (21 CFR 101.12 RACC) and dual-column labels work
Under 21 CFR 101.9(b)(1), a serving is "an amount of food customarily consumed per eating occasion by persons 4 years of age or older". It is not advice on how much to eat. The FDA serving size page says: "By law, serving sizes must be based on the amount of food people typically consume, rather than how much they should consume." Those Reference Amounts Customarily Consumed (RACC) sit in 21 CFR 101.12(b) Table 2. Table 2 RACC values are 30 g for chips, pretzels, and popcorn, 50 g for bread and rolls, and 55 g for dry pasta (140 g prepared) or flavored hot cereal. Plain or fried fish and shellfish entrees use 85 g cooked (110 g uncooked), and bagels or muffins use 110 g. Ice cream uses 2/3 cup, yogurt uses 170 g, milk uses 240 mL (8 fl oz), and carbonated beverages use 360 mL (12 fl oz).
Many small packages hold more than 1 RACC. Under 21 CFR 101.9(b)(6), a product that is packaged and sold individually with less than 200 percent of the RACC must be labeled as one serving. Under 21 CFR 101.9(b)(12)(i), such a product with at least 200 percent and up to and including 300 percent of the RACC must show two columns, per serving and per package. The two-column rule has exceptions, including raw fruits, vegetables and seafood and products on the small-package formats. When cooking from numbered cans (#300, #303, #2.5, #10), check cup volumes in the can size converter.
The FDA 5% low / 20% high Daily Value guide and 21 CFR 101.9 sugars
In FDA consumer guides, "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." A serving that sits between those marks can pass 20% DV once you eat a larger portion. For instance, 2.5 g of saturated fat is 12.5% DV for 1 serving. At 1.5 servings it is 18.8% DV, and at 2 servings it is 25.0% DV.
Notice that Total Sugars has no %DV on any US label. The FDA's label guide says no Daily Reference Value has been established for total sugars. That line mixes natural fruit and milk sugars with added sweeteners. Instead, 21 CFR 101.9(c)(9) sets a 50 g Daily Value for Added Sugars (10% of a 2,000 kcal diet). Convert sugar grams in the sugar to teaspoons tool and sodium in the salt to sodium tool.
21 CFR 101.9(c) rounding increments and the Atwater 4-4-9 check
On a two-column box, each column is rounded by itself, so the container column can differ slightly from the serving column times the serving count. Under 101.9(c)(1), calories round to 0 below 5 kcal and to the nearest 5 kcal up to 50 kcal. Above 50 kcal, calories round to the nearest 10 kcal. Under 101.9(c)(2), fat and saturated fat round to 0 below 0.5 g, to 0.5 g steps below 5 g, and to 1 g steps from 5 g up.
Under 101.9(c)(4), sodium rounds to 0 below 5 mg and to 5 mg steps from 5 to 140 mg. Above 140 mg, sodium rounds to the nearest 10 mg. Under 101.9(c)(6)-(7), carbs, fiber, sugars, and protein go to the nearest gram. A label may show "less than 1 gram" below 1 g and zero below 0.5 g. Under 101.9(c)(1)(i)(B), the 4-4-9 check uses 4 kcal/g for protein, 4 kcal/g for carbs, and 9 kcal/g for fat. Test every step in the label rounding tool.
Video walkthrough
A 3-minute walkthrough of how the nutrition label portion calculator scales every Nutrition Facts line to the amount you ate, or to the whole package.
Read the transcript
What your portion gives you
0:00 How much did that food portion give you?
0:02 It is 1.5 servings, with 420 kcal, on the FDA's own sample lasagna label, where one cup is a serving: 13.5 grams of fat and 1,275 mg of sodium.
0:15 Type the amount eaten beside the label's serving size: 1.5 cups against 1 cup.
0:20 The panel's 280 kcal and 850 mg stay per serving, and scale with the whole portion.
One division, then every line
0:27 First, one thing: its numbers cover the serving size, not the entire package, and every individual line operates that way.
0:34 The calculation starts with one division: the amount eaten over the serving size.
0:39 1.5 divided by 1 is 1.5 servings.
0:42 Then every label line is multiplied by that count.
0:45 Sodium is 850 mg in a serving, so the portion's sodium is printed as 1,280 mg.
0:53 The calories row follows the same count.
0:55 You type in exactly what you consumed: 2 servings.
0:58 Then the totals are 560 kcal, 18 grams of fat and 1,700 mg of sodium: the whole panel is twice one serving.
Percent Daily Value, low to high
1:07 Every Daily-Value line gets a share: sodium is 55.4% and saturated fat 33.8%.
1:15 Fiber is at 21.4%, and then it is protein at 45%.
1:20 An FDA guide calls a nutrient low at 5% or less of the Daily Value per serving.
1:26 An FDA guide calls a nutrient high at 20% or more of the Daily Value per serving.
1:32 In a dish with 2.5 grams of saturated fat per serving, then one serving all by itself is 12.5% of the Daily Value.
1:40 It is 18.8% at 1.5 servings, and then it is 25% at 2 servings.
1:46 It passes the 20% level.
Exact amounts and label rounding
1:49 A printed label rounds each line on its own steps.
1:52 The sodium here is 1,275 mg exactly, and then a label prints 1,280 mg.
1:59 Calories need no rounding at 420 kcal.
2:03 Along the serving multiples, exact and printed label calories agree at every step.
2:07 The lines never part.
2:09 The precise portion consumed is marked on the chart.
2:12 The energy gets a second look: at the standard conversion factors, the macros give 416 kcal, against the label's figure.
The whole package
2:20 The entire package comes next, box and all of it.
2:24 The multiplier becomes the label's servings per container: 4 servings, with 1,120 kcal and 3,400 mg of sodium in total.
2:33 The FDA's guide works the sample label's entire box out to the same answer.
Food in grams, and what to judge
2:38 Precisely the same math works in grams.
2:41 You weigh 80 grams against a 55 gram serving: that is about 1.45 servings, with 291 kcal and 14.5 grams of protein in all.
2:51 One caution comes first.
2:53 The panel assumes the food is mixed evenly, and a serving size is what people typically consume, not a target.
2:59 So 420 kcal and 1,275 mg here are only close estimates, not lab results.
3:06 Try it out at fastcalc.us.
Portion scaling, %DV, and 21 CFR 101.9(c) rounding formulas
servings eaten = portion ÷ serving size (or servings per container, for the whole package) amount eaten = label value per serving × servings eaten share of Daily Value (%) = amount eaten ÷ Daily Value × 100 label %DV = round_half_up(share of Daily Value) (21 CFR 101.9(d)(7)(ii)) Atwater 4-4-9 energy (kcal) = (9 × fat g) + (4 × carbohydrate g) + (4 × protein g)
Worked Nutrition Facts portion examples
The FDA sample lasagna label lists a 1-cup serving and 4 servings per container. One serving has 280 calories, 9 g fat, 4.5 g saturated fat, and 850 mg sodium. It also has 34 g carbs, 4 g fiber, 6 g total sugars, 0 g added sugars, and 15 g protein.
A 1.5-cup portion is 1.5 ÷ 1 = 1.5 servings. That gives 420 calories, 13.5 g fat (17.3% DV), and 6.8 g (6.75 g exact) saturated fat (33.8% DV). Sodium is 1,275 mg (55.4% DV, or 55% label DV). Carbs are 51 g (18.5% DV), fiber is 6 g (21.4% DV), sugars are 9 g, and protein is 22.5 g (45.0% DV). The full box (4 servings) has 1,120 calories and 3,400 mg sodium (147.8% DV).
Two servings (2 cups) of this lasagna give 560 calories and 18 g fat (18 ÷ 78 = 23.1% DV). Sodium doubles to 1,700 mg (1,700 ÷ 2,300 = 73.9%, or 74% DV on the FDA sheet). Weighing food in grams works the same way. Eating 150 g of yogurt from a 227 g serving is 150 ÷ 227 = 0.6608 servings (0.66 servings).
Assumptions, household units, and 21 CFR 101.9 rounding
- Makers round label numbers under 21 CFR 101.9(c): calories to 5 or 10 kcal, fat to 0.5 or 1 g, and sodium to 5 or 10 mg. Main cards show exact scaled values. The 21 CFR 101.9(c) outputs and table columns show re-rounded label values.
- The food is assumed to be mixed evenly, so every bite has the same nutrients per gram as the serving. A label with the word about before servings per container (21 CFR 101.9(b)(8)(i)) gives an estimate for the whole box.
- Cup or piece counts (1 cup, 5 pieces) and gram weights (55 g, 227 g) are rounded separately on the panel. If you weigh food in grams, compare it with the label's gram weight, not the cup size.
- Under 21 CFR 101.9(b)(5)(viii), a label cup is 240 mL, a tablespoon is 15 mL, and a teaspoon is 5 mL. A fluid ounce is 30 mL, and a weight ounce is 28 g. That is rounder than the 236.588 mL US cup and 28.3495 g ounce.
- All %DV figures use the adult targets (2,000 kcal). Lower targets for ages 1 to 3 (1,500 mg sodium, 1,000 kcal) are not used here. The 4-4-9 check counts all carbohydrate at 4 kcal per gram. Under 21 CFR 101.9(c)(1)(i)(C) a label may subtract non-digestible carbohydrate, so it can differ by a few kcal. Lab tolerances in 21 CFR 101.9(g)(4)-(5) (up to 120% for calories, fat, sugars, and sodium; at least 80% for Class II nutrients) are also not applied.
These figures are general information, not medical or dietary advice. Ask a doctor or registered dietitian about your own needs. Terms of use.
What to do with your scaled nutrition numbers
Weigh dry foods in grams on a scale. A cup scoop of cereal, chips, or pasta can differ from the label weight, so weigh it. Enter the gram weight in parentheses on the label (such as 55 g or 30 g under 21 CFR 101.12) as Serving size. Then enter your weighed food as Portion eaten, or resize a batch in the recipe scaler.
Check the 20% DV high mark on your scaled portion. A dish at 14% DV per serving for saturated fat or added sugars passes 20% DV at 1.5 servings, and one at 11% DV passes it at 2 servings. Test any single nutrient in the Daily Value tool.
Turn milligrams and grams into kitchen spoons. A 1.5-serving meal with 1,275 mg of sodium equals 3.29 g (0.55 tsp) of table salt in the salt to sodium tool. You can also convert sugar grams into teaspoons in the sugar to teaspoons tool.
Use the rounded columns to check whole cans or two-column packs. Before heating a whole can of soup or beans, check the can volume in the can size converter. Then check two-column 21 CFR 101.9(c) steps in the label rounding tool.
Nutrition Facts portion and serving size questions
How many calories are in 1.5 servings if one serving is 280 calories?
280 × 1.5 = 420 calories. Every line on the label scales at the same rate, so 9 g of fat becomes 13.5 g and 34 g of carbohydrate becomes 51 g.
How do I work out a whole package from the label?
Pick The whole package and enter Servings per container. That multiplies each line by the serving count. For 4 servings of a 280-calorie lasagna, the box has 4 × 280 = 1,120 calories and 4 × 850 = 3,400 mg of sodium.
The serving size is 55 g and I ate 80 g; what do I enter?
Keep Amount eaten on A portion I enter. Type 55 as Serving size and 80 as Portion eaten. That is 80 ÷ 55 = 1.4545 servings (1.45 servings). With 200 calories and 10 g of protein on the box, you get 290.9 calories (291 kcal) and 14.5 g of protein.
What if I eat two servings?
Every nutrient doubles (2 servings). In the FDA lasagna example (2 cups vs. a 1-cup serving), 280 calories becomes 560 calories, 9 g of fat becomes 18 g, and 850 mg of sodium becomes 1,700 mg.
Is 850 mg of sodium in a serving considered high?
Yes. 850 ÷ 2,300 = 37.0% (37% rounded) of the Daily Value. The FDA guide treats 20% DV or more per serving as high and 5% DV or less as low, so 850 mg is high.
How big is a cup or an ounce on an FDA nutrition label?
Under 21 CFR 101.9(b)(5)(viii), a label cup is 240 mL, so the 1.5-cup default is 360 mL. A tablespoon is 15 mL, a teaspoon is 5 mL, a fluid ounce is 30 mL, and a weight ounce is 28 g.
Sources
- eCFR, 21 CFR 101.9, Nutrition labeling of food (current version)
- eCFR, 21 CFR 101.12, Reference amounts customarily consumed per eating occasion (current version)
- FDA, How to Understand and Use the Nutrition Facts Label (page reviewed Mar 5, 2024)
- FDA, Serving Size on the Nutrition Facts Label (page reviewed Mar 5, 2024)
- FDA, Daily Value on the Nutrition and Supplement Facts Labels (page reviewed Mar 5, 2024)
- FDA, Calories on the Nutrition Facts Label (page reviewed Mar 5, 2024)
- FDA, Added Sugars on the Nutrition Facts Label (page reviewed Mar 4, 2026)
More in Nutrition Calculators and Cooking & Food Calculators.