How do you convert 150 mcg to iu?

To convert micrograms (mcg) to international units (IU), you need to know the specific substance you're converting, as the conversion factor varies by substance. For example, for vitamin D, 1 mcg is equivalent to 40 IU, so 150 mcg of vitamin D would be 6,000 IU. Always check the specific conversion factor for the substance in question to ensure accuracy.