How the health score works
Every scan gives you a single number from 0 to 100. Here's a plain-English look at what goes into it, what it deliberately leaves out, and where it can fall short — so you know exactly how much weight to give it.
The short version
- The score is built from each product's nutrition and ingredient data, sourced from Open Food Facts.
- Higher is better. Broadly, products score better when they're lower in the things UK guidance suggests limiting and simpler in their ingredients.
- It's a way to compare products quickly — not a medical verdict, and not a measure of your whole diet.
- It's only as good as the data on file, which varies from product to product.
On this page
Where the data comes from
Scrannr doesn't hold its own secret list of products. When you scan a barcode, it looks the product up in Open Food Facts — a free, open, community-built database often described as the "Wikipedia of food." From that entry, Scrannr reads the information that matters for a health read: the nutrition figures (the same values you'd find on the back of the pack) and the ingredient list, including any additives and E-numbers.
Because Open Food Facts is maintained by a global community, some products have very complete data and others have gaps. That's a strength — coverage keeps improving, and it's transparent and open — but it also shapes how confident any score can be, which we come back to below.
What the score reflects
The score turns that data into one number from 0 to 100, so you can compare two packets on the shelf without reading either label in full. We describe it here in principle rather than as a formula, and we keep the exact method under review as data and evidence improve.
Broadly, a product tends to score better when it is lower in the nutrients UK health guidance suggests most of us should cut down on — such as saturated fat, salt and sugar — and when its ingredient list is simpler, with fewer additives flagged for a second look. It tends to score worse the more of those it contains. Alongside the number, the app shows a short plain-language verdict so you can read it at a glance.
This is the same broad idea behind nutrient-profiling schemes used across the food world: reward the things worth having more of, and mark down the things worth having less of. The point isn't a perfect measurement of "healthiness" — there's no single agreed formula for that — it's a fast, consistent way to tell products apart.
What it doesn't account for
A single number can't capture everything, and it isn't meant to. The score does not know about:
- Portion size or how much you eat. The score reflects the product, not the amount of it that ends up on your plate.
- Your personal needs. It doesn't account for allergies, intolerances, medical conditions, medications, pregnancy, age, or the goals you're working toward.
- Your overall diet. No single product makes or breaks a balanced diet. A lower-scoring treat can be perfectly fine as part of the bigger picture.
- Freshness, cooking or preparation. How a food is stored, cooked or combined with other foods isn't part of the score.
- Price, ethics or environmental impact. These matter, but they're separate questions from a nutrition-and-ingredients read.
Where the score can fall short
Two honest caveats:
1. It depends on the data. If a product's Open Food Facts entry is missing key nutrition or ingredient information, the score is less reliable — and rather than guess, Scrannr may show a lower-confidence result or no score at all. As the community fills those gaps, scoring gets better.
2. It's a comparison tool, not a diagnosis. Different apps and schemes use different methods, so the same product can score differently in different places. That's normal. Use the score to compare similar products, not as the final word on whether a food is "good" or "bad."
Not medical advice. The health score is a guide to help you compare products. It isn't medical or nutritional advice, and it doesn't replace the product label or the advice of a qualified professional. If you have an allergy or a health condition, always read the label and speak to your GP, pharmacist or a registered dietitian.
How to use it well
- Compare like with like. The score is most useful when you're choosing between two similar products — two breakfast cereals, two pasta sauces — not comparing a biscuit to a bag of spinach.
- Read past the number. Tap in to see the nutrition breakdown, allergens on file and any ingredient flags. That's where the "why" lives.
- Keep the big picture in mind. Aim for balance across your week, not a perfect score on every item.
- Check the label for anything that really matters — especially allergens — because on-pack information is the authoritative source.
Want to go deeper? Our guides explain how to read a UK food label, whether food additives are safe, and what ultra-processed foods are.
The score, answered.
How accurate is the Scrannr health score?
Where does the data behind the score come from?
Why did a product not get a score?
Can I rely on the score for allergies or medical conditions?
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