No secret algorithms: here is exactly how Nutrio rates a product, step by step and with the numbers.
Point your camera at the product's barcode, in the shop or at home. You can also type the code in by hand. Nutrio looks the product up in Open Food Facts, the largest open food database in the world.
From the published information, Nutrio works out a score from 0 to 100 in two open steps: first a baseline from nutritional quality (Nutri-Score) and degree of processing (NOVA); then risky additives subtract directly from that baseline.
You see what counts for and against the product, your own alerts (palm oil, gluten, vegan…) and a page for every additive with its risk rating and the official sources behind it.
The baseline comes from the official Nutri-Score (A–E), which already sums up the good and the bad in the nutrients: that is 85% of the starting point. If the product has no Nutri-Score, we estimate it from its own levels — energy, sugar, saturated fat, salt, fibre, protein — and we say so.
The degree of processing (from NOVA 1, fresh, to NOVA 4, ultra-processed) makes up the remaining 15% of the baseline. The more processed, the lower the starting point.
Additives then subtract directly from the baseline: the orange ones ("use in moderation") and red ones ("high risk") take off a good deal — up to 35 points. In addition, a single red additive prevents a product from being rated "good" or "excellent"; a single orange one prevents an "excellent" rating. Palm oil subtracts 10 points when the prior score is 50 or above, and 5 when it is 49 or below.
Without a Nutri-Score, the baseline is estimated from the nutrition figures and NOVA counts for more; without NOVA, the baseline is nutrition alone. Additives always subtract the same. That way the score never rests on a single figure.
That is the starting point. On top of it, risky additives subtract directly (up to 35 points). A red additive caps the score at 49, while an orange one caps it at 69.
This calculator uses exactly the same formula as the app. Change the values and watch the score take shape in real time. No other app of this kind shows you this.
Loaded example: a cola drink (Nutri-Score E, ultra-processed, with caramel colour and phosphoric acid).
Every additive is rated according to assessments published by official bodies and scientific studies. Its level subtracts directly from the score — the orange and red ones considerably — up to a maximum of 35 points between them all.
The available assessments raise no concern under the authorised conditions of use.
We have not found a conclusive assessment; it subtracts nothing, but it is shown as "no data".
Some assessment flags points to watch in certain contexts or amounts.
There are studies linking frequent consumption with possible adverse effects. It stops the product being rated "excellent".
Assessments recommend limiting consumption. It stops the product being rated "good" or "excellent".
Important: the associations reported by observational studies are not presented as certainties. On each additive page you will see exactly what each source says. And if a figure does not exist in the database, we tell you — we never make it up.
Pick what you want to watch for — gluten, lactose, vegan, vegetarian, pork, sulphites, soya, nuts or egg — and every product page will flag it. Palm oil is always shown. Everything is saved in your browser: no accounts, nothing sent to any server.
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