The circular mil is a unit of area used especially when denoting the cross-sectional size of a wire or cable. It is the equivalent area of a circle whose diameter is 0.001 (10-3) inch, or approximately 0.7854 millionths of a square inch (or 2.5 x 10-7 times picentimeter squared (cm2) can be awkward. To convert circular mils approximately to meters squared (m2), multiply by 5.066 x 10-10. Conversely, multiply by 1.974 x 109. To convert circular mils approximately to centimeters squared (cm2), multiply by 5.066 x 10-6. Conversely, multiply by 1.974 x 105.