Convert IU to mg or mcg with our easy calculators for Vitamins A, D, and E

To convert IU to mcg, or from mcg to IU, simply type the number in either box and hit enter. We’ve pre-populated the boxes with some common values, but you can enter any value you like. Please note that these conversions are relevant for the US and Canada, and may differ for other countries. This is for consumer education and informational purposes only and is not intended to take the place of expert regulatory advice for product labeling.

For more information on how these calculations are made, please see the explanations and example calculations below.

Convert IU to mcg RAE for vitamin A

RAE. Ever heard of it? It’s “retinol activity equivalent” and it’s the new way we talk about vitamin A. Basically vitamin A is important because it’s a source of a molecule called “retinol.” This is the active ingredient that your eye uses to process light. Converting vitamin A from IUs into the new “RAE” unit is easy. We are just converting the IU to mcg or “micrograms.” All you need to do is take the IU and multiply by 0.3 and you will get the mcg RAE. For example:

3000 IU vitamin A * 0.3 = 900 mcg RAE vitamin A

To go the other way just divide:

900 mcg RAE vitamin A / 0.3 = 3000 IU vitamin A

Convert IU to mcg for vitamin D

Most people are used to talking about vitamin D in IU, and that’s not a bad thing. Actually, FDA still allows the use of the IU in parentheses on the supplement facts panel. However, not every company is going to do that, so here is how you calculate. To convert from IU to mcg, just take the IU and divide it by 40. For example:

800 IU vitamin D / 40 = 20 mcg vitamin D

To go the other way, just multiply:

20 mcg vitamin D * 40 = 800 IU vitamin D

For more information on vitamin D, including how much you should take daily, check out our recent post.

Convert IU to mg for vitamin E

Vitamin E is a little more complicated than the other vitamins to convert IU to mg. However, as long as you know whether you are dealing with synthetically-derived or naturally-sourced vitamin E it’s quite easy.

The most common form of vitamin E is the “dl-alpha tocopherol” form. If you see this form, you just multiply the IU by 0.45. For example:

400 IU of vitamin E as dl-alpha * 0.45 = 180 mg vitamin E

To go the other way you just divide:

180 mg vitamin E at dl-alpha / 0.45 = 400 IU vitamin E

If it’s a naturally-sourced vitamin E, you will see it called “d-alpha.” If you see “d-alpha” on the label, just multiply the IU by 0.67. For example:

400 IU of vitamin E as d-alpha * 0.67 = 268 mg vitamin E

To go the other way you just divide:

268 mg vitamin E as d-alpha / 0.67 = 400 IU vitamin E

Convert mcg folic acid to mcg DFE folate

What’s a DFE you might ask? It’s a “dietary folate equivalent.” This is a unit of measure that’s been developed to better equate the biological effects of the folate found in food compared to the synthetic sources of folate such as folic acid and methylfolate. Synthetic sources are more potent at increasing the folate levels in your body compared to food sources. So the amount of DFE provided by these sources is higher.

The conversion is really easy. Just divide the amount of mcg folic acid by 0.6 and you will see the amount of folate mcg DFE you have. For example:

400 mcg folic acid / 0.6 = 667 mcg DFE folate

To go the other way just multiply:

667 mcg DFE folate * 0.6 = 400 mcg folic acid

For more information on how to pick out a high-quality prenatal multivitamin, be sure to check out our recent post.

References

100% Daily Values for Vitamins and Minerals

Here are a few reference tables where you can see the 100% daily values for foods and supplements across different life stages. This is just what goes on the label. You can also check out the Recommended Dietary Allowances for vitamins and minerals from the US Institute of Medicine for more detailed information by age and gender.

On the label – 100% daily values for adults and children ages 4 and up:

On the label – 100% daily values for pregnant and lactating women:

On the label – 100% daily values for children 1-3 years old:

On the label – 100% daily values for infants 1-12 months old:

Sources:

21 CFR Section 101.9.

US Institute of Medicine Dietary Reference Intakes