Tool
IU ↔ mcg converter
Labels in Mexico and the US usually give IU, while European labels and research papers give micrograms. The factor is different for each vitamin, and for E and A it also depends on the form.
IU
Equals
—mcg
This calculator is a guide, not medical advice. It does not replace a health professional, especially if you take prescription medicines or have a medical condition.
Where the numbers come from
- Vitamin D: 1 mcg = 40 IU — labelling conversion used by the NIH Dietary Supplement Label Database
- Vitamin E: 1 IU = 0.67 mg natural (d-alpha-tocopherol), 0.45 mg synthetic (dl-alpha-tocopherol)
- Vitamin A: 1 IU = 0.3 mcg RAE as retinol or supplemental beta-carotene, 0.05 mcg RAE as beta-carotene from food — NIH Office of Dietary Supplements