About the g to mg calculation
One gram is exactly 1,000 milligrams, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The everyday cooking and food-labelling unit in metric countries. The usual unit for medication doses and nutrient quantities.
Formula
mg = g × 1,000
1 g = 1,000 mg
1 mg = 0.001 gWorked example
To convert 500 g, multiply by 1,000: 500 × 1,000 = 500,000 mg.
Frequently asked questions
How many milligrams are in a gram?
There are 1,000 milligrams in one gram. To convert any amount, multiply the number of grams by 1,000.
How do I convert milligrams back to grams?
Divide instead of multiplying, or equivalently multiply by 0.001. One milligram is 0.001 grams.
Is this conversion exact?
Yes. Since the international agreement of 1959, the relationship between grams and milligrams is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.
Where is each of these units used?
Grams: the everyday cooking and food-labelling unit in metric countries. Milligrams: the usual unit for medication doses and nutrient quantities.
Sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units