How Do You Convert 4,000 IU of Vitamin D to Milligrams?

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First, convert the 4,000 IU of vitamin D to micrograms by dividing 4,000 by 40 for a total of 100 micrograms, then convert micrograms to milligrams by dividing 100 by 1,000 for a total of 0.10 milligrams. The abbreviation IU stands for International Unit, and it is an internationally recognized method to measure vitamins, vaccines and other medications.

The volume that an IU measures depends on the substances that are included in each vitamin or medication. This conversion formula is specific to vitamin D, and it does not necessarily apply to other vitamins, which have their own formulas based on the concentration of the substances included.