Mole is a unit of area equal to 3.14 mm2 (same value as π), 1.247 dx2 or 0.00487 in2, taken from the circular area of a 2-millimeter (1.26 dex) diameter mole on the human skin. The unit can be taken for the sake of determining the approximate area of a skin mole, in addition to square millimeters. Despite the unit is taken based from that, the average diameter of a mole is not 2 millimeters; many more moles are smaller than this and many are irregular rather than circular. Some moles can be as big as 8 mm (5 dexes) in diameter (16 moles in area) while some can be as small as 0.5 mm (0.3 dexes) in diameter (0.0625 moles in area); most moles are in the lower half of the range between these examples.