Specific volume () is the volume occupied by a unit of mass of a material. In many cases, the specific volume is a useful quantity to determine because, as an intensive property, it can be used to determine the complete state of a system in conjunction with another independent intensive variable. The specific volume also allows systems to be studied without reference to an exact operating volume, which may not be known (nor significant) at some stages of analysis.
The specific volume of a substance is equal to the reciprocal of its mass density. Specific volume may be expressed in , , , or  .
where,  is the volume,  is the mass and  is the density of the material.
For an ideal gas,
where,  is the specific gas constant,  is the temperature and  is the pressure of the gas.
Specific volume may also refer to molar volume.