Transparent calculator · Labels 1.2
Nutrition Label Decoder
Scale US or EU/UK label values to the amount eaten and show the reference-value arithmetic.
Purpose
What this tool is for
Use this to reconcile a label serving or per-100-unit panel with your actual portion.
Audience
Who it is for
Adults who want transparent label arithmetic in either US %Daily Value or EU/UK Reference Intake mode.
Input glossary
What each field means
| Input | Unit or choice | Why it matters |
|---|---|---|
| Label system | US / EU–UK | Keeps different regulatory definitions and reference values separate. |
| Amount consumed | servings or g/ml | Creates the multiplier applied to each nutrient. |
| Energy and nutrients | kcal, optional kJ, g or mg | Enter only values printed per serving (US) or per 100 g/ml (EU/UK). EU/UK kilojoules are entered separately rather than converted from rounded kcal. |
Method · Labels 1.2
The formula or decision logic
US consumed multiplier = servings consumed; full-container multiplier = labelled servings per container. Consumed or container nutrient = per-serving value × the relevant multiplier. %DV = consumed amount ÷ US Daily Value × 100.
EU/UK multiplier = portion ÷ 100. Per-portion nutrient = per-100 g/ml value × multiplier. %RI = per-portion amount ÷ adult Reference Intake × 100.
US total sugar includes natural and added sugars; added sugar is a labelled subset. EU/UK “of which sugars” is total sugar and is never re-labelled as added sugar.
References support the method or context; they do not validate an individual result. See the sources.
Worked example
Example, not a recommendation: a 1.5-serving cereal bowl
- The US label lists 200 kcal, 400 mg sodium and 10 g added sugar per serving.
- At 1.5 servings: 300 kcal, 600 mg sodium and 15 g added sugar.
- 600 ÷ 2,300 × 100 = 26.1% sodium DV; 15 ÷ 50 × 100 = 30% added-sugar DV.
Interactive calculator
Scale a label to your portion
Nothing you enter is sent to our server. Calculation happens in this browser.
Reproducible checks · 10 October 2026
Check the calculation, not just the claim
These are synthetic arithmetic and input-validation cases—not user records, experiments or proof that an estimate fits an individual. Actual values are generated from the same calculator functions for this release and included in the initial page HTML. Expected values are fixed reference fixtures.
Energy estimates round resting energy to the nearest kcal and composite ranges to the nearest 10 kcal. Label nutrients round to 0.1 g or mg, energy and reference percentages to whole numbers. Blank optional nutrients stay unknown, not zero.
US portion and full package
Pass160 kcal/serving; 1.5 servings eaten; 3/package
- Expected
- 240 kcal eaten; 480 kcal/package
- Actual
- 240 kcal eaten; 480 kcal/package
US sodium and added sugar reference
Pass200 mg sodium + 5 g added sugar/serving; eat 1.5
- Expected
- 300 mg sodium; 13 %DV; 7.5 g added sugar; 15 %DV
- Actual
- 300 mg sodium; 13 %DV; 7.5 g added sugar; 15 %DV
EU / UK per-100 portion
Pass400 kcal + 0.5 g salt/100 g; eat 60 g
- Expected
- 240 kcal; 0.3 g salt; 5 %RI
- Actual
- 240 kcal; 0.3 g salt; 5 %RI
Unknown nutrients stay unknown
PassUS: 1 serving; 0 kcal; nutrient fields omitted
- Expected
- 0 kcal; sodium not shown; added sugar not shown
- Actual
- 0 kcal; sodium not shown; added sugar not shown
Invalid US portion rejected
Pass0 servings
- Expected
- Servings consumed must be between 0.1 and 100.
- Actual
- Servings consumed must be between 0.1 and 100.
Invalid US portion rejected
Pass-1 servings
- Expected
- Servings consumed must be between 0.1 and 100.
- Actual
- Servings consumed must be between 0.1 and 100.
Invalid US portion rejected
Pass101 servings
- Expected
- Servings consumed must be between 0.1 and 100.
- Actual
- Servings consumed must be between 0.1 and 100.
Invalid US portion rejected
PassMissing / non-finite servings
- Expected
- Servings consumed must be between 0.1 and 100.
- Actual
- Servings consumed must be between 0.1 and 100.
Contradictory sugars rejected
PassAdded sugar 9 g; total sugar 8 g
- Expected
- Added sugar cannot exceed total sugar.
- Actual
- Added sugar cannot exceed total sugar.
Validation boundaries are software scope limits, not health thresholds. A passing fixture checks arithmetic and display behaviour, not clinical validity. Method sources and limitations
Limitations
What the result cannot tell you
- %DV and %RI are population reference values, not personal targets.
- The result depends entirely on accurate package values and portion measurement.
- The tool does not reproduce every jurisdictional rounding rule.
- No score labels a food “healthy” or “unhealthy.”
Questions specific to this tool
Frequently asked questions
Is total sugar the same as added sugar?
No. On a US label, added sugar is part of total sugar. An EU/UK “sugars” line usually does not identify how much was added.
Why does an EU label use values per 100 g?
The standard base makes products easier to compare. This tool multiplies those values by your portion divided by 100.
Does “no added sugar” mean sugar-free?
No. A product may still contain naturally occurring sugar; read the total-sugars line and ingredients.
Should %DV be multiplied for more than one serving?
Yes. This tool scales the nutrient amount first, then calculates the reference percentage for what was eaten.
Why can my result differ from the front of pack?
The package may use different rounding or a different reference basis. Check serving size, jurisdiction and whether values are per serving or per 100 units.
Evidence and official references
Sources
How to understand and use the Nutrition Facts Label
US Food and Drug Administration · Current
Supports: US serving and %DV interpretationIndustry resources on changes to the Nutrition Facts Label
US Food and Drug Administration · Current
Supports: Protein %DV quality-correction context and current US labelling requirementsRegulation (EU) No 1169/2011
European Union · 2011
Supports: EU declarations and Reference IntakesNutrition legislation information sheet
UK Government · Current
Supports: Current UK nutrition-labelling sources and jurisdiction notesFound a numerical or source issue? Send a correction with the page URL.
Apply the method
One label, three portions
Apply the same arithmetic to the FDA example label before using your own package.
Read Eugene Blago’s field note