Millimeters are smaller than centimetres. 1 centimetre is equal to 10 millimetres in the metric system. One can also compare both of these measurements to the metre to find the answer.
Using a table for converting metric units, you can see that 1 centimetre is the same as 1/100 of a metre. In the same way, 1 mm is equal to 1/1,000 of a metre. A centimetre is clearly bigger than a millimetre.
To compare in inches, you can also change from the metric system to the imperial system. Using conversion tables, you can see that 1 centimetre is equal to 0.3937 inches and 1 millimetre is equal to 0.03937 inches. When you look at these numbers side by side, you can also see that a centimetre is bigger.