abbreviation

mg

MIL-ih-gram

Mg (abbreviation) means Milligram: a unit of mass equal to one thousandth of a gram, used mainly for doses of medicine and nutrients. Example: “Take one 500 mg tablet twice a day.”

abbreviation

Milligram: a unit of mass equal to one thousandth of a gram, used mainly for doses of medicine and nutrients.

"Take one 500 mg tablet twice a day."

"Each capsule contains 200 mg of caffeine."

symbol

chemistry Written Mg, the chemical symbol for magnesium.

"The alloy is mostly aluminium with a small amount of Mg."

How to Use Mg

Learner’s notes

In plain EnglishA very small unit of weight, one thousandth of a gram, used for medicine doses.

When to use it

Standard abbreviation; written lowercase with no full stop and a space after the number.

Memory tip

Lowercase mg is a milligram; capital Mg is the element magnesium.

Easily confused with

mcg ml → Mg →

Common pairings

500 mg mg per day mg dose mg/dL

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Can you complete this real example?

Take one 500 _____ tablet twice a day.

Synonyms

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milligram milligramme

Related Words

milligram

Frequently Asked Questions

How many mg are in a gram?

There are 1,000 milligrams in one gram, and 1,000,000 milligrams in a kilogram. So 500 mg is half a gram.

What is the difference between mg and mcg?

A milligram is a thousandth of a gram; a microgram, written mcg or µg, is a thousandth of a milligram. Confusing the two on a medicine label means a thousandfold dosing error, which is why mcg is usually spelled out.

What is the difference between mg and ml?

Milligrams measure mass and millilitres measure volume. They only match up if you know the density of the substance, so 5 mg and 5 ml are not the same amount.

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