The density of a substance is defined as

Density is an important physical property for characterizing a material or chemical system. Mathematically, density is calculated as a substance's mass per the volume it occupies. The formula for density is $\mathrm{d}=\frac{\mathrm{M}}{\mathrm{V}}$, where $\mathrm{d}$ is density, $\mathrm{M}$ is mass, and $\mathrm{V}$ is volume. Density is commonly expressed in units of grams per cubic meter $(\mathrm{g}/{\mathrm{m}}^3)$.