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Food Label Calculator: Nutrition Facts per Serving & per 100 g
This free food label calculator converts nutrition values between per serving and per 100 g/ml, kJ and kcal, and salt and sodium. It runs entirely in your browser: nothing you type is sent, stored or tracked. Enter only the fields you have. Blank fields stay blank in the result, because Nyamly never turns a missing value into a zero.
Worked example: a label says 150 kcal per 30 g serving. 150 × 100 ÷ 30 = 500 kcal per 100 g.
Per serving ↔ per 100 g/ml
Enter the serving size and whichever values are printed on the label — per serving or per 100 g/ml — and this converts to the other basis. Leave any nutrient blank if the label doesn't give it.
| Nutrient | Per serving | Per 100 g |
|---|
kJ ↔ kcal
1 kcal = 4.184 kJ. Type into either field; the other fills in.
Salt ↔ sodium
Salt = sodium × 2.5 — the standard conversion factor used on nutrition labels (see how we score). Salt is entered in grams, sodium in milligrams, matching how each is usually printed.
How to use the food label calculator
- Choose a direction: "I have per-serving values" if the label lists per serving, or "I have per-100 g/ml values" if it lists per 100 g/ml.
- Enter the serving size from the label and pick g or ml.
- Type the nutrient values printed on the label. Leave blank any the label does not give. The other basis fills in as you type.
- For energy or salt, use the kJ ↔ kcal and salt ↔ sodium fields below the table.
How to read the result
Comparing products
Per-100 g/ml figures are the only fair way to compare two products, because serving sizes are set by the manufacturer and vary product to product. Nyamly's own Low/Medium/High nutrient bands, explained on how we score, are also defined per 100 g/ml for exactly this reason.
A blank result means "not given", not zero
If you leave a nutrient blank, its converted value stays blank too — shown as "—". This mirrors Nyamly's own rule for scanned products: a nutrient the app never received a value for is shown as unknown, never silently treated as zero.
Rounding
Results are rounded to two decimal places for readability. For exact figures, use the original label.
Frequently asked questions
How do I convert a nutrition label from per serving to per 100 g?
Multiply each per-serving value by 100 and divide by the serving size in grams (or ml). Example: 150 kcal per 30 g serving is 150 × 100 ÷ 30 = 500 kcal per 100 g. The calculator does this for every nutrient you enter.
How many kJ are in a kcal?
1 kcal = 4.184 kJ. Type into either the kcal or the kJ field and the other fills in.
How do I convert sodium to salt?
Salt = sodium × 2.5. In this calculator salt is entered in grams and sodium in milligrams, matching how each is usually printed: 480 mg of sodium is 1.2 g of salt.
Does the calculator store or send what I type?
No. It runs entirely in your browser; nothing you type is sent, stored or tracked.
What happens if I leave a field blank?
It stays blank in the result, shown as "—". A missing value is never turned into a zero.
Can I skip typing the label?
Yes. Nyamly, an iPhone app that is free to download, reads a product's nutrition facts straight from its barcode, so there is no manual entry and no photographing a label.
Skip typing the label: scan the barcode
Nyamly is an iPhone calorie tracker and barcode scanner, free to download. It reads a product's nutrition facts straight from its barcode — no manual entry, no photographing a label.