### The milligram is the mass equal to 1/1,000 of a gram, or 0.0154 grains.
The milligram, or milligramme, is an SI unit of weight in the metric system. In the metric system, "milli" is the prefix for 10-3. Milligrams can be abbreviated as mg; for example, 1 milligram can be written as 1 mg.