Millimeters to decimeters conversion table shows the most common values for the quick reference. Alternatively, you may use the converter below to convert any other values. 1 Millimeter = 0.01 Decimeter. 1 Decimeter = 100 Millimeters. Millimeter is a metric length unit and equal to one thousandth of a meter. The abbreviation is mm. Decimeter is a metric length unit and equals to one tenth of a meter. The abbreviation is dm.