How to convert milligrams to micrograms
Formula: mcg = mg × 1,000
Worked example: 500 mg → 500 × 1,000 = 500,000 mcg
1,000 micrograms make one milligram. Supplement labels mix both units, for example 1,000 mcg of vitamin B12 is 1 mg. Double check doses when switching units: an error here is a factor of 1,000.
Milligrams to micrograms conversion chart
| Milligrams (mg) | Micrograms (mcg) |
|---|---|
| 1 mg | 1,000 mcg |
| 2 mg | 2,000 mcg |
| 3 mg | 3,000 mcg |
| 4 mg | 4,000 mcg |
| 5 mg | 5,000 mcg |
| 6 mg | 6,000 mcg |
| 7 mg | 7,000 mcg |
| 8 mg | 8,000 mcg |
| 9 mg | 9,000 mcg |
| 10 mg | 10,000 mcg |
| 12 mg | 12,000 mcg |
| 15 mg | 15,000 mcg |
| 20 mg | 20,000 mcg |
| 25 mg | 25,000 mcg |
| 30 mg | 30,000 mcg |
| 40 mg | 40,000 mcg |
| 50 mg | 50,000 mcg |
| 75 mg | 75,000 mcg |
| 100 mg | 100,000 mcg |
| 250 mg | 250,000 mcg |
| 500 mg | 500,000 mcg |
| 1,000 mg | 1,000,000 mcg |
What is a milligram?
The milligram is one thousandth of a gram. It is the everyday unit of medicine doses (a regular aspirin tablet holds 325 mg), caffeine content and the sodium, cholesterol and mineral lines of a Nutrition Facts label.
What is a microgram?
The microgram is one millionth of a gram, written µg in science and mcg on US drug and supplement labels to avoid confusion with mg. Vitamin D, vitamin B12 and folate doses are given in micrograms because the amounts are so small.