Nutrition Label Reader — Decode Any Nutrition Label Instantly

What this tool analyses

Enter the values from any packaged food label and click Analyse Label to get six data outputs: a macro breakdown by percentage of calories, a protein density score, a sugar ratio, a sodium check against the WHO daily limit, a traffic-light quality summary, and — if you consumed more than one serving — scaled totals for your actual intake.

All calculations are per serving as declared on the label. No account is required, no data leaves your device.

How each metric is calculated

Macro breakdown uses gram weights directly: protein contributes 4 kcal/g, carbohydrates 4 kcal/g, and fat 9 kcal/g. Percentages are derived from the sum of these calculated kilocalories rather than from the label’s stated calorie figure. This avoids compounding rounding errors that arise because labels round each macro to the nearest gram before printing.

Protein density divides protein kilocalories by the label’s stated calorie count, then multiplies by 100. Using the label calorie figure here — rather than the recalculated total — keeps this score consistent with how dietitians typically express it in research and practice.

Sugar ratio is sugars ÷ total carbohydrates × 100. It captures how much of the carbohydrate fraction is made up of simple sugars, which is a more diagnostic number than either figure alone.

Sodium check expresses sodium as a percentage of the WHO’s 2,000 mg daily limit [2], making the absolute number meaningful across foods with very different serving sizes.

Protein density: the most useful single metric

Most food labels present protein in grams, but grams alone are misleading when comparing foods with different calorie densities. A 100 g serving of boiled chicken breast (about 31 g protein, 165 kcal) has a protein density of approximately 75% — meaning three-quarters of its calories come from protein. A protein bar claiming 20 g protein but delivering 400 kcal has a density of only 20%.

Research by Leidy et al. (2015) demonstrated that higher dietary protein — particularly at breakfast — reduces appetite, preserves lean mass during energy restriction, and supports long-term weight maintenance [1]. Protein density operationalises this principle into a single number you can read from any label.

Thresholds used in this tool:

Score	Protein Density	What it means
Poor	< 15%	Most of the calories come from carbs or fat
Fair	15–29%	Moderate protein contribution
Good	30–44%	Solid protein-to-calorie ratio
Excellent	≥ 45%	High protein density; prioritise this food in a deficit

Sugar ratio: what the carbs are made of

Total carbohydrates on a label include starch, fibre, and sugars. The sugar ratio isolates simple sugars as a share of total carbs, which reveals foods that appear moderate in carbohydrates but deliver most of those carbs as fast-digesting sugars.

A sugar ratio above 50% is common in flavoured yoghurts, cereals, sauces, and sports drinks. A ratio below 25% is typical of whole grains, legumes, and vegetables. The traffic-light thresholds in this tool follow a conservative read: ≤25% green, 26–50% amber, >50% red.

Sodium: the invisible budget item

The WHO 2023 guideline recommends adults consume less than 2,000 mg of sodium per day — equivalent to approximately 5 g of table salt [2]. A single serving of processed soup, deli meat, or instant noodles routinely accounts for 30–50% of that budget.

This tool expresses sodium as a percentage of the WHO daily limit rather than as a raw milligram figure, because the absolute number is difficult to contextualise without a reference point. A reading above 25% of the daily limit in a single serving warrants attention, particularly if that food is consumed multiple times per day.

Saturated fat: context matters

The saturate ratio — saturated fat as a share of total fat — is flagged in the traffic-light summary when you enter saturate data. A ratio above 50% is classified red, 34–50% amber, and ≤33% green.

Astrup et al. (2020) argued in a meta-analysis that the health effect of saturated fat depends on the overall food matrix and what replaces it in the diet [3]. The traffic-light in this tool flags high saturate ratios as a prompt for further consideration, not as a verdict. Foods high in saturated fat from dairy or unprocessed meat have a different risk profile than processed foods with the same saturate ratio.

Frequently asked questions

What is protein density and why does it matter?

Protein density measures the percentage of a food’s total calories that come from protein. It is calculated as (protein grams × 4) ÷ total calories × 100. A score above 30% is considered good; above 45% is excellent. High protein density is the most reliable proxy for a food’s satiety and muscle-retention value per calorie, making it more actionable than protein grams alone when comparing two foods with different calorie counts.

How is the sugar ratio calculated?

The sugar ratio is sugars ÷ total carbohydrates × 100. A ratio above 50% means more than half of the carbohydrates in a food are simple sugars, which digest rapidly and offer little satiety. Whole foods like oats or legumes typically score below 10%; many flavoured yoghurts and breakfast cereals score above 60%.

What does the WHO sodium limit of 2,000 mg mean in practice?

The World Health Organization recommends consuming less than 2,000 mg of sodium per day to reduce the risk of hypertension and cardiovascular disease (WHO, 2023). This tool expresses each food’s sodium content as a percentage of that limit so you can see at a glance how much of your daily budget a single serving uses.

Why do the macro percentages sometimes not match the label exactly?

Nutrition labels round values to the nearest gram, which introduces small rounding errors when you recalculate from macros to calories. This tool calculates macro percentages from the declared gram weights (protein × 4, carbs × 4, fat × 9) rather than from the label’s calorie figure to avoid compounding those rounding artefacts. The label calorie figure is still used for the protein density score.

Are saturated fats always harmful?

Current evidence does not support classifying all saturated fats as uniformly harmful. A 2020 meta-analysis in the Journal of the American College of Cardiology found that the effect of saturated fat on cardiovascular risk depends heavily on the food matrix and what replaces it in the diet. However, most health bodies, including the WHO and the European Food Safety Authority, continue to recommend limiting saturated fat to less than 10% of total energy intake as a general precaution. This tool flags high saturate ratios as amber or red to surface potential concern — not as a definitive health verdict.

Does serving size affect the analysis?

The macro breakdown, protein density score, sugar ratio, and sodium check are all calculated per serving as declared on the label. If you enter a number of servings greater than one, the tool adds a Scaled Totals section showing your actual intake across all servings consumed. This is useful when you eat two or three servings in one sitting, which is common for snacks and cereals.

Sources

1. Leidy HJ, Clifton PM, Astrup A, Wycherley TP, Westerterp-Plantenga MS, Luscombe-Marsh ND, Woods SC, Mattes RD (2015). The role of protein in weight loss and maintenance. The American Journal of Clinical Nutrition. PMID 25926512 DOI
2. World Health Organization (2023). Sodium intake for adults and children: updated 2023 guideline. World Health Organization. Link
3. Astrup A, Magkos F, Bier DM, Brenna JT, de Oliveira Otto MC, Hill JO, King JC, Mente A, Ordovas JM, Volek JS, Yusuf S, Krauss RM (2020). Saturated fats and health: a reassessment and proposal for food-based recommendations. Journal of the American College of Cardiology. PMID 32562735 DOI