Convert grams to milligrams
Enter a value in grams (g) to get milligrams (mg). One gram is 1,000 milligrams; one milligram is 0.001 grams.
How to use the Gram to milligram
- Type the number of grams.
- Click Convert.
- Read the result in milligrams, plus the same value in every other weight & mass unit.
g to mg formula
milligrams = grams × 1,000. To go the other way, grams = milligrams × 0.001 (see milligrams to grams).
Worked example
12 g × 1,000 = 12,000 mg.
Grams to milligrams conversion table
| Grams | Milligrams |
|---|---|
| 0.1 g | 100 mg |
| 0.5 g | 500 mg |
| 1 g | 1,000 mg |
| 2 g | 2,000 mg |
| 3 g | 3,000 mg |
| 5 g | 5,000 mg |
| 10 g | 10,000 mg |
| 20 g | 20,000 mg |
| 25 g | 25,000 mg |
| 50 g | 50,000 mg |
| 100 g | 100,000 mg |
| 250 g | 250,000 mg |
| 500 g | 500,000 mg |
| 1,000 g | 1,000,000 mg |
About the gram
One thousandth of a kilogram; the kitchen and postal unit across the metric world.
About the milligram
One thousandth of a gram. Medicine doses and nutrition labels use milligrams.
Related conversions
Frequently asked questions
How many milligrams in a gram?
1,000 milligrams.
How many grams in a milligram?
0.001 grams.
Is the factor exact?
The factor 1,000 is derived from the units' exact definitions; only the display is rounded.
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Last updated 2026-09-23.