The cubic inch and the cubic foot are still used as units of volume in the United States. One popular use is for engine capacity, also called cubic inch displacement. The common SI units of volume, the liter, milliliter, and cubic meter, are also used, especially in manufacturing and high technology. One cubic foot is equal to exactly 1,728 cubic inches because 12 = 1,728. One cubic inch equals 16.39 cubic centimeters.