Why does 148 calories become 150 on a label?

Because above fifty calories the required increment is ten, so the only permitted values are 60, 70, 80 and so on. Rounding 148 to 145 is not allowed and is among the commonest errors producers make. Below fifty the increment is five, and anything under five calories may be declared as zero. The rule applies to the calculated amount per serving before any other rounding, so work from the unrounded figures throughout.

Can a label say 0g when there really is something there?

Yes, and it is legal. Anything under half a gram of fat declares as zero, so a serving with 0.49g of trans fat prints 0g. Across a container of eight servings that is up to 3.9g behind the zero. This is the rule working as written rather than a trick, but it is also why the FDA cites misdeclared trans fat more than any other labelling problem — the temptation is to shrink the stated serving until the number disappears, and serving sizes are not free to choose for exactly that reason.

Why do the numbers not scale smoothly when I change the servings?

Because rounding is applied to each serving, not to the recipe. Halve the portions and the underlying figure halves, but the declared figure jumps to whichever step it now lands on. A dish with 60.9g of fat declares 30g at two servings, 5g at twelve and 3g at twenty — all of which multiply back to about 60g, but none of which reconstruct it exactly. It is a good reason not to add a day together from labels and expect the total to balance.

Is a calculated label good enough to put on a product?

Usually not on its own. A calculated panel is a legitimate starting point and many producers begin here, but a label on a product for sale has to satisfy 21 CFR 101.9 in full — including a serving size taken from the published reference amounts for that food category rather than one you pick, the added sugars line, the vitamin and mineral block, and the exact wording of the footnote. Most producers verify against laboratory analysis before printing, and the small-business exemptions that exist are narrower than people assume.

Where do I get nutrition figures for my ingredients?

From the packet where there is one, since that reflects the actual product. Otherwise USDA FoodData Central is the standard free reference and covers most raw ingredients. This page deliberately holds no database of its own — a built-in table would have to guess which variety, brand and fat content you bought, and a confident wrong number is worse than an honest blank. Whatever you enter, the panel inherits its accuracy.

Does cooking change the nutrition?

Water loss does not, and that is the part this page models. Reducing a sauce concentrates everything into less weight, so a serving weighs less while containing the same calories. What genuinely does change is harder: some vitamins degrade with heat, fat can render out and be poured away, and moisture moves between components. None of that is modelled here, and none of it is captured by simply weighing the pan before and after.

How is % Daily Value worked out?

It is the amount in a serving divided by the Daily Value for that nutrient, on a 2,000-calorie basis, expressed as a whole percent. The current values come from the 2016 final rule — 78g of total fat, 20g saturated, 2,300mg sodium, 275g carbohydrate, 28g fibre and 50g added sugars. Older references still circulate with pre-2016 numbers, which is one of the four failures the FDA most often cites. Protein carries no percentage unless a claim is made about it.

Can I choose my own serving size?

Not for a product you sell. The FDA publishes reference amounts customarily consumed for hundreds of food categories, and your serving size derives from the category your product falls into rather than from what you would prefer to declare. Serving sizes that do not match the published amount are among the most frequently cited violations, precisely because a smaller stated serving makes every number on the panel look better. For a recipe you are cooking at home, cut it however you like — the arithmetic here works either way.

What is missing from the panel this page draws?

Cholesterol, added sugars, and the mandatory block of vitamin D, calcium, iron and potassium — all of which a panel for sale must carry with both absolute amounts and percentages. The footnote also has to appear in specific wording. What is here is the core macronutrient calculation with the rounding done correctly, which is the part most calculators get wrong; the remainder is a formatting exercise once the numbers are right.

Should I trust these numbers if I am counting for medical reasons?

Treat them as an estimate and verify anything that matters. A calculated figure inherits every assumption underneath it — that the database entry matches your ingredient, that the mixture is even, that each serving is the same size, that nothing stuck to the pan. For carbohydrate counting, allergy management or any medically directed diet, the packaging on what you actually bought is a better source than any calculation, and your clinician or dietitian is a better source than either.

Recipe Nutrition Label Calculator

The arithmetic on a nutrition panel is the easy part. Add the ingredients, divide by the servings. What separates a real label from a spreadsheet is the rounding, and those rules are stranger than they look. They are set out in 21 CFR 101.9(c) and they are not ordinary rounding. Calories go to the ...

This is a calculation, not a laboratory analysis. It applies the FDA rounding rules correctly to whatever nutrient data you put in, which makes it useful for understanding a recipe and for drafting — but a panel on a product you sell has to satisfy 21 CFR 101.9 in full, including a serving size taken from the published reference amounts rather than chosen, and most producers verify against laboratory results before printing. If you are managing a medical condition, or cooking for someone with an allergy, treat these figures as an estimate and check the actual packaging.

THE INGREDIENTS

Grams used, then the nutrition per 100g from the packet or from USDA FoodData Central. This page holds no food database of its own — inventing one would be guessing at your ingredients.

Item

grams

Cal

Fat

Sat

Trans

Carb

Fib

Sug

Prot

SERVINGS

WEIGHT LOST COOKING (%)

Something real is declaring as zero. Trans fat is 0.24g a serving, which prints as 0g because anything under 0.5g must. Across 6 servings that is 1.47g in the dish. This is the rule working as written rather than a mistake — but it is also why misdeclared trans fat is the commonest violation the FDA writes to producers about.

Rounding is applied per serving, so it does not survive multiplication. Cut this into 6 and the label says 10g of fat, which multiplies back to 60.0g against a real total of 60.9g — a gap of 0.9g. Change the serving count and the gap changes with it, which is worth knowing before anyone adds up a day from labels.

Total weight raw

915 g

After cooking loss

915 g

Serving weight

153 g

Calories, unrounded

329.8

Calories, declared

330

Fat, unrounded

10.16 g

Fat, declared

10 g

Sodium, unrounded

38.7 mg

Sodium, declared

40 mg

Whole recipe calories

1,979

What this cannot know. It uses the numbers you supply, so it inherits their accuracy — a database entry for a generic ingredient may sit some way from the particular one in your kitchen. It assumes nothing is lost to the pan or the plate, that everything is mixed evenly, and that each serving is identical. Nutrients also change with cooking beyond simple water loss, and none of that is modelled here. For a product you sell, this is a starting point for a conversation with a laboratory rather than a substitute for one.

THE PANEL

Nutrition Facts

6 servings per recipe

Serving size about 153g

Amount per serving
Calories330

% Daily Value*

Total Fat 10g13%

Saturated Fat 4.5g24%

Trans Fat 0g

Sodium 40mg2%

Total Carbohydrate 51g19%

Dietary Fiber 5g19%

Total Sugars 16g

Protein 10g

* The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Values rounded per 21 CFR 101.9(c). Cholesterol, added sugars and the vitamin and mineral block are omitted here — a panel for sale needs them.

The rule is a staircase, not a line. Every flat tread is a band of real values that all print the same number, and every riser is a point where one more gram changes what the label says. It is why 148 calories declares as 150 and there is no legal value of 145 anywhere above fifty.

Live calculation · updates as you type

Created with❤️byeaglecalculator.com

HOW TO USE

1
Enter each ingredient by weight in grams, then its nutrition per 100g. Take those figures from the packet in front of you or from USDA FoodData Central rather than from memory — the whole panel inherits their accuracy.
2
Set the number of servings. Watch what happens to the declared values as you change it: they do not scale smoothly, because each one lands on whichever rounding step it falls into.
3
Add a cooking loss percentage if the dish reduces. That changes the weight of a serving, not its nutrition — what evaporates is water, and none of the calories leave the pan.
4
Check the panel against the unrounded figures beside it. Where a value declares as zero but is not zero, the page says so, because that gap is the one worth understanding.

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Last updated: August 1, 2026 · Rounding per 21 CFR 101.9(c) · Daily Values from the 2016 final rule · A calculation from your data, not a laboratory analysis.