Food labels in the US switched from IU to mcg RAE in 2020 because carotenoids from plants are converted to vitamin A much less efficiently than preformed retinol. The upper limit of 3,000 mcg a day applies only to preformed vitamin A (retinol), not to beta-carotene from food.
How to use the Vitamin A Calculator
- Amount
- Form of vitamin A
- Sex
- Status
- Age
- Every result field is editable: type into Vitamin A and Amount plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the amount on the label and choose the form. The calculator converts it to mcg RAE and shows what share of your RDA it provides.
Inputs explained
| Field | What to enter |
|---|---|
| Amount | In IU |
| Form of vitamin A | Choose one: Retinol / retinyl esters (preformed), Beta-carotene supplement, Beta-carotene from food, Other carotenoids from food |
| Sex | Choose one: Male, Female |
| Status | Choose one: Not pregnant or breastfeeding, Pregnant, Breastfeeding |
| Age | In years |
What each result means
- Vitamin A = [Amount]×[Form of vitamin A]
- Share of your RDA = [Vitamin A]÷[Your RDA]×100
Example values
How the main result changes when Amount changes and everything else stays at the example values above:
| Amount (IU) | Vitamin A (mcg RAE) |
|---|---|
| 2,500 | 750 |
| 3,750 | 1,125 |
| 5,000 | 1,500 |
| 6,250 | 1,875 |
| 7,500 | 2,250 |
| 10,000 | 3,000 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Retinol: 1 IU = 0.3 mcg RAE
Supplemental beta-carotene: 1 IU = 0.15 mcg RAE (2 mcg = 1 mcg RAE)
Dietary beta-carotene: 1 IU = 0.05 mcg RAE (12 mcg = 1 mcg RAE)
Other dietary carotenoids: 1 IU = 0.025 mcg RAE (24 mcg = 1 mcg RAE)
Worked example
Inputs — Amount: 5,000 IU; Form of vitamin A: Retinol / retinyl esters (preformed); Sex: Male; Age: 30 years.
Results — Vitamin A = 1,500 mcg RAE; Your RDA = 900 mcg RAE/day; Share of your RDA = 167 %; Compared with the adult upper limit (3,000 mcg retinol) = Well below the limit.
Key terms
- RAE
- Retinol activity equivalent.
- IU
- International unit.
Frequently asked questions
How many IU of vitamin A do I need?
900 mcg RAE for men (3,000 IU retinol) and 700 mcg RAE for women (2,333 IU retinol).
Can you take too much vitamin A?
Yes – long-term intakes above 3,000 mcg retinol a day can harm the liver, bones and an unborn baby.
Why do carotenoids count less?
Only part of beta-carotene from food is absorbed and converted to vitamin A.