Density is an important property of a gasket material, since it has an inverse relationship to the void volume of the material. Density is often used in a specification, since relationships to sealability, compressibility, creep relaxation, and tensile strength can be found for a given gasket grade.

Density is a measurement of the mass to the volume ratio and therefore easily determined with a weight scale and thickness measuring device. This test method requires from 1 h to two days of sample conditioning, which is necessary to achieve a high level of precision, but which detracts from its usefulness as a production test method. Where it must be modified for manufacturing control, it is recommended that thickness and weight measurement methods be adhered to strictly.