There are 5000 IU in 125 mcg of vitamin D. That's the result of multiplying the number of IU in an mcg of vitamin D (40 IU per mcg) by the number of micrograms in this example (125):
Number of IU = Amount in mcg × 40 IU per mcg
Number of IU = 125 × 40 IU per mcg = 5000 IU Read more