How to Change IU to MG

Pills may be standard sizes, but the potency of what's in them can vary enormously.

International Units, or IU, are used in medicine and healthcare. Unlike most units, which are fixed regardless of what is measured, International Units vary from drug to drug. They describe the potency of a drug, not its mass or volume. Since each drug has a different potency 1 IU of drug "A" may be lighter or heavier, and have a smaller or larger volume than 1 IU of drug "B." To convert from IU to milligrams you must know the IU data for the drug being converted.

Things You'll Need

• Calculator

Instructions

1. Enter the number of International Units into the calculator. For example, if converting 5,000 IU of vitamin A, enter 5,000.

2. Multiply the value from Step 1 by the internationally agreed mass of one IU of the measured drug. For example, in the case of vitamin A, where a single IU has a mass of 0.3 micrograms 5,000 IU has a mass of 5,000 x 0.3, or 1,500 micrograms.

3. Divide the value in micrograms by 1,000, which is the number of micrograms in a milligram. The result is the IU for that specific drug, expressed in milligrams.

   For example, 5,000 IU of vitamin A has a mass of 1.5 mg -- 1,500 / 1,000 = 1.5.

Tips & Warnings

• Every drug has its own IU data sheet. Information can be found online at the web sites of drug manufacturers and at specialist medical web sites.

• Incorrect drug calculations can have severe and fatal consequences. Never calculate your own medication. Seek advice from qualified medical professionals.

References

• University of North Carolina at Chapel Hill; How Many? A Dictionary of Units of Measurement; Russ Rowlett; July 2005
• Dietary Supplement Ingredient Database: MVM Calculator Frequently Asked Questions
• Extension Toxicology Network: How Much Is A Part Per Million?