Hi Elizabeth, I hope you made a mistake and you typed cc (instead of c"m)..... cause c"c is cucic centimeter and it's a measure of volume.... and you can convert volume to volume (and not to something that is a measure of length). 25.4 m"m or 2.54 c"m = 1 inch. 0.3937 inch = 1 c"m = 10 m"m ...