Convert milligrams to grams (and back) — with the full weight family, from milligrams to tonnes.
Advanced options
converted value
| 100 mg | 0.1 g |
| 250 mg | 0.25 g |
| 500 mg | 0.5 g |
| 1,000 mg | 1 g |
| 2,500 mg | 2.5 g |
| 5,000 mg | 5 g |
How to use this tool
Type any amount (fractions and decimals allowed).
Choose the From and To units, or tap Swap to reverse the conversion.
The result, the per-unit rate and the full unit family are shown together, live as you type.
The reference table covers the values people look up most, so you can sanity-check at a glance.
Formula & worked example
500 mg = 0.5 g. A 250 mg tablet is 0.25 g, and 1,000 mg is exactly 1 g.
Limitations — read this before you rely on it
Milligrams and grams measure mass, not volume: 500 mg of a liquid is not automatically 0.5 ml unless its density is 1 g/ml.
Frequently asked questions
1,000 mg in 1 gram.
500 mg = 0.5 g — just divide milligrams by 1,000.
100 mg = 0.1 g.
Divide by 1,000. For example, 2,500 mg / 1,000 = 2.5 g.
Yes — a milligram is one-thousandth of a gram, so mg numbers are always 1,000x larger for the same mass.