A conversion taught in school and worth remembering the rest of your life is 1 inch equals 25.4 milimeters(2.54 centimeters), exactly. With this you can convert any linear dimension, such as miles to kilometers, feet to meters, cubic inches to cubic centimeters. The conversion Dr1Drive gave, 16.387, is arrived at by muliplying 2.54 X 2.54 X 2.54 to give the number of cubic centimeters in a cubic inch.