Mg, short for milligrams, and mcg, short for micrograms, measures the mass of an object. Both units are metric units, which use the gram as the base unit. The prefix "milli-" stands for 10^-3, meaning a milligram equals 0.001 g. The prefix "micro-" stands for 10^-6, meaning a microgram equals 0.000001 g. Therefore, it takes 1,000 mcg to equal just 1 mg. Knowing this conversion factor allows you to quickly convert from milligrams to micrograms.
Multiply the mass in milligrams by 1,000 to convert to micrograms. For example, if you have 59 mg, multiply 59 by 1,000 to get 59,000 mcg.
Divide the number of milligrams by 0.001 to convert to micrograms. In this example, verify your answer by dividing 59 by 0.001 to get 59,000 mcg.
Verify your answer with an online milligrams-to-micrograms calculator. Enter the number of milligrams and the number of micrograms will appear.