Article
% of reference values: what the percentage really means
On every food page of this site, a “% NRV” column sits next to the values per 100 g. That percentage compares the food’s content with a reference amount set for an average adult. Here is what it measures, and what it does not.
A reference value is a labelling benchmark
Nutrient reference values (NRVs) are, for the most part, amounts written into Swiss law: annex 10 of the ordinance on food information (the Swiss FIC ordinance). Their job is to express a content as a percentage on a label, so that two products stay comparable. They describe an average adult, with no distinction of age or sex.
This site uses those amounts for the “% NRV” column. * One exception: annex 10 sets no value for dietary fibre. The 30 g a day used here is an indicative benchmark with no legal status; it serves only as a reading scale. The main ones:
| Nutrient | Reference value (adults) |
|---|---|
| Energy | 2,000 kcal |
| Protein | 50 g |
| Dietary fibre* | 30 g |
| Calcium | 800 mg |
| Iron | 14 mg |
| Magnesium | 375 mg |
| Potassium | 2,000 mg |
| Vitamin C | 100 mg |
| Vitamin D | 5 µg |
| Vitamin B12 | 2.5 µg |
| Folate | 200 µg |
How the figure is worked out is documented page by page: /en/methodology/.
Why it is not your personal target
An NRV is a single benchmark, designed for labels rather than for a person. It does not shift with age, sex or activity level, and it does not shift during pregnancy or breastfeeding. The benchmarks published by nutrition societies, by contrast, do vary on all of those points.
In practice, “30% of the NRV” for protein means “30% of 50 g”, and nothing else. The share that represents in your own day may be larger or smaller. For an order of magnitude that takes height, weight, age and activity into account, the site has a separate tool: /en/needs-calculator/.
That leaves the percentage one job: placing foods relative to each other at an equal quantity of 100 g. To see two of them with their percentage columns side by side, use the comparison tool: /en/comparator/.
Why some percentages go above 100%
The FSVO database states every value per 100 g of the product as described. When 100 g of a food holds more than a nutrient’s reference value, the percentage climbs past 100%. That is not a glitch: it is the signature of a concentrated food, often dried, milled or powdered.
Four examples read from the database:
- /en/food/cocoa-powder-deoiled-without-sugar/: 51 mg of iron per 100 g, about 364% of the 14 mg reference.
- /en/food/whitefish-raw/: 22.1 µg of vitamin D, about 442% of the 5 µg reference.
- /en/food/parmesan-cheese/: 1,340 mg of calcium, about 168% of the 800 mg reference.
- /en/food/wheat-bran-raw/: 45.1 g of dietary fibre, about 150% of the 30 g indicative benchmark.
The percentage always follows the quantity on screen: move the portion selector from 100 g to 15 g and it is recalculated accordingly. The tops of the rankings obey the same rule. See /en/foods-high-in-iron/ and /en/foods-high-in-calcium/.
Nutrients with no reference value
Not every line on a food page carries a percentage. Annex 10 sets a reference value for energy, the macronutrients and a series of vitamins and minerals, not for everything the FSVO database measures. Two cases come up often.
- Omega-3 fatty acids, which are polyunsaturated fatty acids: the database gives a content in grams, with no labelling reference. /en/food/flaxseed-oil-cold-pressed/ holds 49.82 g per 100 g; the figure appears, the percentage column stays empty. The ranking still exists: /en/foods-high-in-omega-3/.
- Water, recorded for every food: raw cucumber holds 96.3 g per 100 g. It is a composition figure, and no percentage can be attached to it.
This absence is not the same thing as “n/a”. “n/a” means the source publishes no value for that food; here the value exists, but no official reference matches it.
Where these percentages appear on the site
The calculation shows up in three places.
- On a food page: the “% NRV” column of the composition table, and the note “% of nutrient reference values (adults)” under the headline values. The portion selector recalculates both.
- In the per-nutrient rankings, where each food is placed by its content per 100 g and by its share of the reference value: see /en/foods-high-in-protein/ or /en/foods-high-in-fibre/, with everything gathered here, /en/rankings/.
- In the comparison tool, when two foods are set side by side: /en/comparator/.
The database covers 1,216 generic foods across 19 families, with up to 22 components per food. The percentage is calculated only for components that have a reference value; the others stay in grams, milligrams or micrograms. To browse the whole set: /en/foods/.