Weight

mcg to mg Converter

Convert micrograms (mcg / µg) to milligrams (mg) instantly, there are 1,000 mcg in a mg, with a full equivalents table. Handy for supplement and medication labels.

Result

0.5 mg

Equivalent weight

Your value in micrograms, milligrams, and grams.

How it works

A microgram is one thousandth of a milligram. Both are common on supplement and medicine labels, where mcg and µg mean the same thing. Converting is a factor of 1,000.

mg = mcg ÷ 1,000
1 mg = 1,000 mcg · 1 g = 1,000 mg

Worked example

500 mcg equals 500 ÷ 1,000 = 0.5 mg.

Micrograms on supplement labels

A microgram is one millionth of a gram, and there are 1,000 micrograms in a milligram, so mg = mcg ÷ 1,000. Labels write micrograms as mcg or µg. Vitamins such as B12, folate, vitamin D and vitamin K are dosed in micrograms because the amounts are so small.

Micrograms	Milligrams
50 mcg	0.05 mg
100 mcg	0.1 mg
250 mcg	0.25 mg
400 mcg	0.4 mg
500 mcg	0.5 mg
1,000 mcg	1 mg
2,500 mcg	2.5 mg
5,000 mcg	5 mg

Vitamin D is often also listed in international units: 1 mcg of vitamin D equals 40 IU, so 25 mcg is 1,000 IU. That IU conversion is specific to each vitamin and does not apply to others.

Daily values for nutrients measured in mcg

Daily Values (DV) used on US supplement labels for adults, and tolerable upper intake levels (UL) where set:

Nutrient	Daily Value	Upper limit (adults)
Vitamin D	20 mcg (800 IU)	100 mcg (4,000 IU)
Vitamin B12	2.4 mcg	not set
Folate	400 mcg DFE	1,000 mcg from supplements and fortified foods
Vitamin K	120 mcg	not set
Biotin	30 mcg	not set
Iodine	150 mcg	1,100 mcg
Selenium	55 mcg	400 mcg
Vitamin A	900 mcg RAE	3,000 mcg preformed vitamin A

Converting IU to mcg or mg

Nutrient	Conversion
Vitamin D	1 mcg = 40 IU
Vitamin A (retinol)	1 IU = 0.3 mcg RAE
Vitamin E (natural)	1 IU = 0.67 mg
Vitamin E (synthetic)	1 IU = 0.45 mg

Avoid the 1,000× mistake

mcg (micrograms) and mg (milligrams) differ by a factor of 1,000, so mixing them up is a serious dosing error.
Some labels write µg instead of mcg; both mean micrograms.
Prescriptions sometimes write "mcg" in full because "µg" can be misread as "mg".
If a label or prescription is unclear, ask a pharmacist before taking it.

Frequently asked questions

How many mcg are in 1 mg?

1,000 mcg.

How do I convert mcg to mg?

Divide by 1,000, 500 mcg = 0.5 mg.

Is 1,000 mcg the same as 1 mg?

Yes. 1,000 micrograms equal 1 milligram.

How many IU is 25 mcg of vitamin D?

1,000 IU. For vitamin D, 1 mcg = 40 IU.

How many mcg of vitamin D should I take?

The Daily Value is 20 mcg (800 IU) for adults, and the upper limit is 100 mcg (4,000 IU) unless a doctor advises otherwise.

Is µg the same as mcg?

Yes. Both are abbreviations for microgram, one millionth of a gram.

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