The specific volume of a substance is the volume occupied by a unit mass of that substance. In other words, it is the amount of space occupied by one kilogram of the substance. Specific volume is the reciprocal of density. It provides a measure of how much volume a unit mass of substance occupies, and it is commonly used in thermodynamics and fluid mechanics to characterize the properties of substances, particularly fluids. The specific volume ($v$) of a substance, including fluids, is the volume occupied by a unit mass of the substance. It is the reciprocal of density ($\rho$). The formula for specific volume is:

Where:

• $v$ is the specific volume,
• $\rho$ is the density of the substance.