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Nutrition & Supplements

Transparent calculators that add up your supplements and compare them with official reference intakes and upper limits from the US (NIH) and the EU (EFSA).

Vitamin & Mineral Intake Calculator

Vitamin and mineral intake calculator: see the US RDA or AI and the EU PRI or AI with upper limits for 23 nutrients, by age, sex, pregnancy and breastfeeding.

Supplement Stack Calculator

Supplement stack calculator: add up vitamins and minerals from all your products, spot nutrients you take twice and compare totals with US and EU upper limits.

Supplement Label Analyzer

Supplement label analyzer: paste a Supplement Facts label to see each vitamin and mineral against US and EU upper limits, including overlap with other products.

Supplement Dose Calculator

Supplement dose calculator: enter a vitamin or mineral, the amount per serving and servings per day to see your intake as a share of the RDA and upper limit.

Vitamin D Calculator

Vitamin D calculator: convert IU to µg, add food and other supplements, and compare your daily vitamin D with the US RDA, EU AI and the 100 µg upper limit.

Elemental Mineral Calculator

Elemental mineral calculator: convert the weight of magnesium citrate, calcium carbonate, zinc gluconate, ferrous sulfate and more into the elemental amount.

Magnesium Calculator

Magnesium calculator: find the elemental magnesium in magnesium citrate, glycinate, oxide, malate, taurate and threonate, and compare it with the upper limit.

IU Converter

IU converter for vitamins: convert international units to micrograms or milligrams and back for vitamin D, vitamin A (retinol, beta-carotene) and vitamin E.

Reference data, not recommendations

These tools do not tell you what to take. They add up the amounts you enter and place them next to published reference values, so you can see where you stand and discuss it with a doctor, pharmacist or dietitian.

Two sets of reference values are shown side by side:

  • US Dietary Reference Intakes, published by the National Academies and summarised in the NIH Office of Dietary Supplements fact sheets: the Recommended Dietary Allowance (RDA), Adequate Intake (AI) and Tolerable Upper Intake Level (UL).
  • EFSA Dietary Reference Values from the European Food Safety Authority: the Population Reference Intake (PRI), Adequate Intake (AI) and Tolerable Upper Intake Level, updated for vitamin B6, selenium, folate, manganese, iron and vitamin A between 2023 and 2024.

The two authorities sometimes differ considerably. The EU upper limit for vitamin B6 is 12 mg per day, while the US limit is 100 mg; for zinc the limits are 25 mg and 40 mg. Seeing both helps you understand why advice differs between countries.

Which tool should I use?

Start with the vitamin and mineral intake calculator to see the reference values for your age and sex. Use the supplement stack calculator to add up everything you take, or the label analyzer to check a single product against what you already use. The elemental mineral calculator and the IU converter translate label amounts – such as magnesium citrate or vitamin D in IU – into the units the reference values use.

Scope and limitations

The reference values cover healthy adults aged 19 and over, including pregnancy and breastfeeding. They are not targets for individuals, and upper limits do not apply to people taking a supplement under medical supervision. Food also contributes vitamins and minerals; most upper limits apply to your total intake.

Sources