How many milligrams are in a gram?

1 g = 1000 mg. To convert any amount, multiply by 1000.

How do you convert grams to milligrams?

Multiply the number of grams by 1000 to get milligrams. The formula is shown in the "How it's calculated" section above.

Where does the conversion factor come from?

It's a published international standard. Most are defined exactly by international agreement (e.g. 1 inch = 25.4 mm exactly, 1 lb = 0.45359237 kg exactly). Source citations are listed under the formula above.

Unit converter — Mass

Grams to milligrams converter

Convert grams (g) to milligrams (mg). Source-cited conversion factor, exact to the displayed precision.

Results are mathematically exact for the displayed precision. How we calculate.

How it's calculated

Convert grams to milligrams— the formula

Grams convert to milligrams by multiplying by the published conversion factor. The factor below is exact to the precision shown, sourced from the citation under the formula.

mg = g × 1000

g = mg × 0.001

Mass: SI base unit (BIPM). Avoirdupois conversions: 1 lb = 0.45359237 kg (international agreement 1959); 1 oz = 1/16 lb; 1 stone = 14 lb.

Questions

Frequently asked questions

How many milligrams are in a gram?
1 g = 1000 mg. To convert any amount, multiply by 1000.
How do you convert grams to milligrams?
Multiply the number of grams by 1000 to get milligrams. The formula is shown in the "How it's calculated" section above.
Where does the conversion factor come from?
It's a published international standard. Most are defined exactly by international agreement (e.g. 1 inch = 25.4 mm exactly, 1 lb = 0.45359237 kg exactly). Source citations are listed under the formula above.