1. Both density and relative density measures the amount of matter available in a unit volume.
2. Density measures a direct physical
property, though relative density tells a density of a material in terms
of another material.
3. Density has dimensions and measuring units, whereas relative density is dimensionless and doesn’t have a measuring unit.
4. An object at particular conditions can
have only one density, though it may have many relative densities with
respect to different reference materials.