mcg to IU Converter

Your details

Choose whether you are starting from a mcg/mg dose and want IU, or vice versa.
The conversion factor differs by vitamin and form. Natural and synthetic vitamin E have different potencies.
Enter the dose you want to convert. For Vitamin E, enter milligrams (mg) when converting to IU, and IU when converting to mg.
Converted doseWithin safe range
1,000

Result in the target unit

% of upper limit (UL)25%
% of daily value (RDA/AI)166.7%
Upper limit (IU)4,000
RDA / AI (IU)600
25% % of UL
Low dose<20Within safe range20-75Approaching limit75-100Above safe limit100+

25 mcg = 1000.00 IU

  • Conversion factor: 1 mcg of Vitamin D (D2 or D3) equals 40 IU.
  • This dose is 167% of the recommended dietary allowance or adequate intake for adults.
  • This dose is 25% of the adult upper intake limit (UL) of 4,000 IU. You are within the safe range.

Next stepAlways read your supplement label to confirm the form of the vitamin (natural vs. synthetic for E, retinol vs. beta-carotene for A) because the conversion factor differs.

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