How many milligrams are in 1 gram?

There are exactly 1,000 milligrams in one gram. The prefix 'milli-' means one-thousandth, so a milligram is one-thousandth of a gram.

How do I convert grams to milligrams?

Multiply the number of grams by 1,000. For example, 0.5 grams × 1,000 = 500 milligrams. Simply move the decimal point three places to the right.

When should I use milligrams instead of grams?

Use milligrams for drug dosages, vitamin and mineral content, blood test results, and chemical reagent amounts. Use grams for food weights, body measurements, and larger quantities. The general rule: if the number would be less than 1 gram, express it in milligrams.

Grams to Milligrams (g to mg) Converter

1 g = 1,000 mg

1 Gram equals 1,000 Milligrams (1 g = 1,000 mg). Convert Grams to Milligrams with formula, table, and examples.

One gram equals exactly 1,000 milligrams. This conversion is critical in medicine, pharmacology, nutrition, and chemistry, where precise small-mass measurements determine drug dosages, nutritional content, and chemical reagent quantities.

How to Convert Grams to Milligrams

mg = g × 1,000

Multiply the value in Grams by 1,000

Take your value in Grams
Multiply by 1,000
Read the result in Milligrams

Common Grams to Milligrams Conversions

Grams (g)	Milligrams (mg)	Status
1 g	1,000 mg
2 g	2,000 mg
5 g	5,000 mg
10 g	10,000 mg
25 g	25,000 mg
50 g	50,000 mg
100 g	100,000 mg
500 g	500,000 mg
1,000 g	1,000,000 mg

Good to Know About Grams to Milligrams Conversion

In medicine, confusing grams with milligrams is a 1,000-fold error that can be fatal. This is why medical prescriptions and pharmacy labels are carefully checked for unit accuracy, and 'mcg' is used instead of 'µg' to prevent misreading.

Grams to Milligrams: What You Need to Know

A 500 mg paracetamol tablet is 0.5 grams. A daily vitamin D recommendation of 15 micrograms can also be expressed as 0.015 milligrams or 0.000015 grams. Nutrition labels convert between grams and milligrams for different nutrients: fat in grams, sodium in milligrams. Precise conversion between these units can be a matter of patient safety.

What is a Gram? g

A metric unit of mass equal to one thousandth of a kilogram. Widely used in cooking, nutrition labeling, and science.

Metric cooking nutrition labels postal weight

Learn more about Gram →

What is a Milligram? mg

A metric unit of mass equal to one thousandth of a gram, or one millionth of a kilogram. Commonly used in medicine and pharmacology.

Metric medicine pharmacology nutrition

Learn more about Milligram →

Going the other way? Use our Milligrams to Grams converter.

Grams to Milligrams FAQ

There are exactly 1,000 milligrams in one gram. The prefix 'milli-' means one-thousandth, so a milligram is one-thousandth of a gram.
Multiply the number of grams by 1,000. For example, 0.5 grams × 1,000 = 500 milligrams. Simply move the decimal point three places to the right.
Use milligrams for drug dosages, vitamin and mineral content, blood test results, and chemical reagent amounts. Use grams for food weights, body measurements, and larger quantities. The general rule: if the number would be less than 1 gram, express it in milligrams.

Non-Frequently Asked Questions About Grams to Milligrams

Questions nobody should ask - but someone did.

A standard paperclip weighs about 1 gram. A US dollar bill weighs exactly 1 gram. A raisin weighs about 1 gram. These are the holy trinity of gram references. Every science teacher has used at least one of them.