IU to µg (mcg) converter
Vitamin D, A and E between international units (IU) and micrograms (µg, also written mcg) or milligrams, with the conversions the site’s price comparisons use.
Converter
25 µg
Vitamin D: IU and µg
1 µg of vitamin D3 (cholecalciferol) or D2 is 40 IU, so 1 IU is 0.025 µg.
| IU | µg |
|---|---|
| 200 IU | 5 µg |
| 400 IU | 10 µg |
| 800 IU | 20 µg |
| 1,000 IU | 25 µg |
| 2,000 IU | 50 µg |
| 3,000 IU | 75 µg |
| 4,000 IU | 100 µg |
Vitamin A: IU and µg
1 µg of retinol (as in retinyl palmitate or acetate) is 3.333 IU, so 1 IU is 0.3 µg.
| IU | µg |
|---|---|
| 1,000 IU | 300 µg |
| 2,000 IU | 600 µg |
| 3,333 IU | 1,000 µg |
| 5,000 IU | 1,500 µg |
| 10,000 IU | 3,000 µg |
Vitamin E: IU and mg
1 mg of natural vitamin E (d-alpha-tocopherol) is 1.49 IU, so 1 IU is 0.671 mg.
| IU | mg |
|---|---|
| 10 IU | 6.71 mg |
| 30 IU | 20.1 mg |
| 100 IU | 67.1 mg |
| 200 IU | 134 mg |
| 400 IU | 268 mg |
Forms that convert differently
An IU measures activity, so its weight depends on the form. The vitamin A figures above are for retinol; beta-carotene converts differently. The vitamin E figures are for natural vitamin E (d-alpha-tocopherol); synthetic vitamin E (dl-alpha-tocopherol) has less activity per milligram. A label names the form it contains.
These convert figures printed on labels; they are not amounts to take. If you take medication, are pregnant or have a health condition, check with a pharmacist or GP.
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