To help compare different orders of magnitude this page lists lengths between 10â2 m and 10â1 m (1 cm and 10 cm). 1  1 cm â 10 millimeters. 2  1 cm â 0.39 inches. 3  1 cm â edge of square of area 1 cm2.  1 cm â edge of cube of volume 1 1  ml. 1 cm â approximate width of average fingernail.  1.5 cm â length of a very large mosquito.