Formula reference

Milligram–microgram conversion

1 mg = 1000 mcg

Milligrams and micrograms differ by a factor of 1000. To go from mg to mcg multiply by 1000 (decimal three places right); from mcg to mg divide by 1000.

What each part means

mgMilligram
mcgMicrogram (1/1000 of a mg)

Worked example

0.25 mg = 250 mcg; 400 mcg = 0.4 mg.