Density (symbol: ? - Greek: rho) is a measure of mass per unit of volume. The higher an object's density, the higher its mass per volume. The average density of an object equals its total mass divided by its total volume. A denser object (such as iron) will have less volume than an equal mass of some less dense substance (such as water).

The SI unit of density is the kilogram per cubic metre (kg/m3)

where

? is the object's density (measured in kilograms per cubic metre)

m is the object's total mass (measured in kilograms)

V is the object's total volume (measured in cubic metres)