The cubic inch (symbol in<sup>3</sup>), sometimes abbreviated cu in, is a unit of volume in the Imperial units and United States customary units systems. 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 of a US gallon.
The cubic inch and the cubic foot are used as units of volume in the United States, although the common SI units of volume, the liter, milliliter, and cubic meter, are also used, especially in manufacturing and high technology. One cubic inch is exactly .
One cubic foot is equal to exactly , as 12<sup>3</sup> = 1728.
Notation conventions
- The following abbreviations have been used to denote the cubic inch: cubic in, cu inch, cu in, cui, cu. in.
- The IEEE standard symbol is: in<sup>3</sup>