A centimeter is ten times larger than a millimeter. The centimeter is 0.01 meters (10-2 m) , whereas the millimeter is 0.001 meter (10-3 m). In other words, one centimeter equals ten millimeters. Whereas an inch is much bigger, one inch is equal to 2.54 centimeters.
A millimeter is about the thickness of an eye lash, an inch is about the length of the middle of your pointer finger, and a centimeter is about the length of your pinky nail. Also, centimeter and millimeter are not customary like inches is. Inches is most commonly used in the USA while millimeters and centimeters are most commonly used every where else, and are based on 10's and 100's.