The centimeter cubed per gram (symbolized cm 3 /g) is the standard unit of specific volume in the centimeter-gram-second ( cgs ) or small-unit metric system. Specific volume is the reciprocal of density .
A substance with a specific volume of 1 cm 3 /g has the same density as water. Materials with higher density have lower specific volume; materials with lower density have higher specific volume.
Alternative units are often used to express specific volume. The most common of these is the meter cubed per kilogram (m 3 /kg). A substance with a specific volume of 1 m 3 /kg has a specific volume of 1000 cm 3 /g. Conversely, a substance with a specific volume of 1 cm 3 /g has a specific volume of 0.001 m 3 /kg.