1 mg is how many iu?
From IU to mg: IU * 0.67 = mg. From mg to IU: mg * 1.5 = IU see less In the metric system, 1000 milligrams (mg) is a unit of mass equal to 1 gram and 1000 micrograms (mcg) is equal to 1 milligram (mg). An IU (International Unit) is a unit of measurement for vitamins and other specific biologically active substances.