Mcg to Mg Converter — Micrograms to Milligrams

How to convert micrograms to milligrams

Divide the micrograms by 1,000:

milligrams = micrograms ÷ 1,000

2,500 mcg ÷ 1,000 = 2.5 mg. Dividing by 1,000 moves the decimal point three places to the left, so 25 mcg is 0.025 mg, not 0.25 mg. To go the other way, multiply milligrams by 1,000 — type the milligrams into the second field and the micrograms follow.

This page converts amounts only. How much of a vitamin or medicine to take is a question for the label and your doctor or pharmacist.

Micrograms to milligrams chart

Micrograms (mcg)	Milligrams (mg)
1 mcg	0.001 mg
5 mcg	0.005 mg
10 mcg	0.01 mg
25 mcg	0.025 mg
50 mcg	0.05 mg
100 mcg	0.1 mg
200 mcg	0.2 mg
250 mcg	0.25 mg
400 mcg	0.4 mg
500 mcg	0.5 mg
1,000 mcg	1 mg
1,500 mcg	1.5 mg
2,000 mcg	2 mg
2,500 mcg	2.5 mg
3,000 mcg	3 mg
5,000 mcg	5 mg

To convert several amounts at once — every line of a supplement facts panel, for example — open Convert a list of values and paste the micrograms one per line.

Comparing two labels

The units on two bottles often differ, and the bigger number is not always the bigger amount. Convert both to the same unit first:

Label A	Label B	In the same unit	Larger amount
500 mcg	1 mg	0.5 mg vs. 1 mg	B
2,500 mcg	2 mg	2.5 mg vs. 2 mg	A
1,000 mcg	1 mg	1 mg vs. 1 mg	the same
400 mcg	0.4 mg	0.4 mg vs. 0.4 mg	the same

mcg, µg and IU

mcg and µg are the same unit, the microgram. U.S. labels and prescriptions write mcg; scientific texts use µg. You may also see ug where the µ symbol is not available.
mg is the milligram: 1,000 micrograms.
IU (international unit) is not a unit of mass. It measures biological activity, so there is no single mcg-to-IU factor. For vitamin D, the NIH Office of Dietary Supplements gives 1 mcg = 40 IU — so 25 mcg of vitamin D is 1,000 IU. Supplement Facts labels now list vitamin D in mcg, sometimes with IU beside it.

Micrograms appear on labels for nutrients needed in tiny amounts — vitamin B12, vitamin D, biotin, iodine, selenium and vitamin K — while milligrams are used for larger ones such as vitamin C, calcium and magnesium. Folate is a special case: labels list it in mcg DFE (dietary folate equivalents), which adjusts for how well different forms are absorbed, so mcg DFE and plain mcg of folic acid are not interchangeable either.

The metric prefixes step by 1,000: micrograms to milligrams to grams to kilograms. For grams and kilograms, see grams to kilograms; for food weights in grams and ounces, grams to ounces and ounces to grams.

Frequently asked questions

How many mcg are in a mg?

1,000. Micro means one millionth and milli one thousandth, so one milligram is 1,000 micrograms and one microgram is 0.001 milligram.

Is 1,000 mcg the same as 1 mg?

Yes, exactly. A label that says 1,000 mcg and one that says 1 mg describe the same amount of the substance.

Which is bigger, mcg or mg?

A milligram is 1,000 times bigger than a microgram. 500 mcg is half a milligram, so 500 mcg is less than 1 mg — even though 500 looks like the larger number.

What does µg mean?

µg is the scientific symbol for microgram (µ is the Greek letter mu, for micro). Labels and prescriptions in the U.S. usually write mcg instead, because a handwritten µg can be misread as mg (the Institute for Safe Medication Practices lists µg as an error-prone abbreviation).

Can I convert mcg to IU?

Not with a single factor. An international unit (IU) measures biological activity, and the conversion depends on the substance. For vitamin D, 1 mcg equals 40 IU, according to the NIH Office of Dietary Supplements; other vitamins use different factors.

How many mg is 5,000 mcg?

5 mg. Divide by 1,000: 5,000 mcg ÷ 1,000 = 5 mg.