Is a milliliter equivalent to a milligram?

A milliliter (mL) and a milligram (mg) are not equivalent measurements because they represent different concepts in the metric system. A milliliter is a unit of volume, which measures the space that a liquid occupies. On the other hand, a milligram is a unit of mass, which indicates how much matter is present in an object or substance.

Because they measure different properties, a direct equivalency between them cannot be established without knowing the density of the substance being measured. For instance, one milliliter of water weighs approximately one gram, so it contains 1,000 milligrams. However, the relationship changes with substances of different densities. Thus, it is essential to recognize the distinction and the lack of a general equivalence between these two units. This is foundational knowledge in pharmacology, as medication dosages often need precise measurements of both volume and mass.