How to convert micrograms to milligrams
Formula: mg = mcg × 0.001
Worked example: 10 mcg → 10 × 0.001 = 0.01 mg
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.
Micrograms to milligrams conversion chart
| Micrograms (mcg) | Milligrams (mg) |
|---|---|
| 1 mcg | 0.001 mg |
| 2 mcg | 0.002 mg |
| 3 mcg | 0.003 mg |
| 4 mcg | 0.004 mg |
| 5 mcg | 0.005 mg |
| 6 mcg | 0.006 mg |
| 7 mcg | 0.007 mg |
| 8 mcg | 0.008 mg |
| 9 mcg | 0.009 mg |
| 10 mcg | 0.01 mg |
| 12 mcg | 0.012 mg |
| 15 mcg | 0.015 mg |
| 20 mcg | 0.02 mg |
| 25 mcg | 0.025 mg |
| 30 mcg | 0.03 mg |
| 40 mcg | 0.04 mg |
| 50 mcg | 0.05 mg |
| 75 mcg | 0.075 mg |
| 100 mcg | 0.1 mg |
| 250 mcg | 0.25 mg |
| 500 mcg | 0.5 mg |
| 1,000 mcg | 1 mg |
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.
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.