mcg to mg Converter
Enter an amount in micrograms to get milligrams -- an exact divide-by-1,000 conversion, with a reference table at common values.
Milligrams
0.500 mg
Reference table at common values
| mcg | mg |
|---|---|
| 50 | 0.050 |
| 100 | 0.100 |
| 250 | 0.250 |
| 500 | 0.500 |
| 1,000 | 1.000 |
| 2,500 | 2.500 |
| 5,000 | 5.000 |
| 10,000 | 10.000 |
The formula
Unlike the ml conversions elsewhere on this site, converting mcg to mg needs no density or concentration -- it's a fixed relationship between two metric prefixes, exact by definition:
mg = mcg ÷ 1,000
Worked example
The calculator's own default: 500 mcg ÷ 1,000 = 0.500 mg -- a common vitamin B12 or vitamin D supplement amount, shown here only as an example of the arithmetic, not a dosing recommendation.
Need a concentration-based conversion instead, like a liquid medicine label? mg to ml Calculator. Converting the step above instead -- mg to g? mg to g Converter.
Frequently Asked Questions
How many mcg is 1 mg?
1 mg is exactly 1,000 mcg -- "milli-" means one thousandth and "micro-" means one millionth of the base unit (the gram), so a milligram is exactly 1,000 times larger than a microgram, by definition of the SI prefixes, not a measured or rounded ratio.
Is mcg the same as µg?
Yes -- mcg and µg (using the Greek letter mu) both mean microgram. "Mcg" is common on US supplement and medicine labels specifically because µ doesn't display reliably on every device or in plain text; both mean exactly one millionth of a gram.
Why do vitamin labels use mcg instead of mg?
Many vitamins and hormones are active in very small amounts -- vitamin B12 and vitamin D, for example, are commonly dosed in micrograms because a milligram amount would be a huge overdose. Using mcg keeps the printed number a normal size instead of a long decimal in mg.
Does this involve a density or concentration, like the mg to ml pages?
No -- this is a pure metric-prefix conversion (divide by 1,000), exact for any substance, with nothing to look up. It doesn't need a density or a label concentration the way milliliter conversions do.
These are conversions, not measurements -- a density or concentration you enter or pick determines the answer, and real ingredients and products vary by brand. Nothing here is medical, dosing or pharmacist advice; confirm any medicine amount against the actual product label and your pharmacist or prescriber. See the Terms.