mcg to mg Converter: Micrograms to Milligrams

Mcg to Mg

mcg to mg Converter

Convert micrograms to milligrams and back

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A microgram (mcg or µg) is one-millionth of a gram, and a milligram (mg) is one-thousandth of a gram. These small units are used for vitamin dosages, medications and trace nutrients.

1 milligram = 1,000 micrograms, exact by SI metric definition. Enter a value in either field below and the other updates automatically.

Micrograms (mcg)

Milligrams (mg)

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Micrograms

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Milligrams

Calculation

Vitamin dosages, medication labels, and trace nutrient amounts are often listed in micrograms on one source and milligrams on another, this converter switches between the two instantly using the exact SI metric relationship.

How to use this mcg to mg converter

Enter a value in the Micrograms (mcg) field to see the equivalent in milligrams.
Or enter a value in the Milligrams (mg) field to see the equivalent in micrograms, either field updates the other automatically.

What this converter does

A microgram (mcg or µg) is one-millionth of a gram, and a milligram (mg) is one-thousandth of a gram, both small metric units commonly used for vitamin dosages, medications, and trace nutrients where a full gram would be far too large a unit to be practical.

1 milligram (mg) = 1,000 micrograms (mcg / µg), exact by SI metric definition

Why this conversion matters for dosages

A mismatch between mcg and mg is a factor-of-1,000 error, exactly the kind of unit confusion that matters most in medication and supplement dosing, where reading “500 mcg” as “500 mg” (or vice versa) would represent a massive dosing error. This tool exists to make that specific conversion fast and unambiguous, though it’s always worth double-checking the units printed directly on a medication label or prescription rather than relying on a conversion after the fact.

Frequently asked questions

How many micrograms are in a milligram?

Exactly 1,000 micrograms (mcg) make up 1 milligram (mg), by SI metric definition.

Why does the mcg vs mg distinction matter so much for supplements and medication?

Because the difference is a factor of 1,000, confusing the two units on a dosage could mean taking 1,000 times more or less than intended. Always confirm the unit printed on the actual product label or prescription, and consult a healthcare professional for dosage questions.