It is the volume of a cube with each of its three dimensions (length, width, and height) being one inch long which is equivalent to 1⁄231 of a US gallon.

Because of the extensive export of electrical equipment to other countries, some usage of the non-SI unit can be found outside North America.

The cubic inch was formerly used by the automotive industry and aircraft industry in North America (through the early 1980s) to express the nominal engine displacement for the engines of new automobiles, trucks, aircraft, etc.

The cubic inch is still used for this purpose in classic car collecting.

The auto industry now uses liters for this purpose, while reciprocating engines used in commercial aircraft often have model numbers based on the cubic inch displacement.