# Circular mil conversions

The circular mil conversion selector here selects the area/surface measurement unit to convert to starting from circular mils (cmil). To make a conversion starting from a unit of area other than circular mil, simply click on the "Reset" button.

## About circular mil

The **circular mil** is a unit of area in the Imperial and US customary systems of units equal to 5.067 × 10^{-10} square meters (1 circular mil = 5.067 × 10^{-10} m^{2}), the standard derived unit of area in the International System of Units (SI).

The circular mil (cmil) is also equal to 5.067 × 10^{-6} square centimeters (cm^{2}), or 0.0005067 square millimeters (mm^{2}), or 506.7 square micrometers (μm^{2}) or 506.7 × 10^{6} square nanometers (nm^{2}) (units of area in the SI), or about 0.7853 square mils (sq mil), or 7.853 × 10^{-7} square inches (sq in) or 5.454 × 10^{-9} square feet (sq ft), which are Imperial / US customary units of area.

The circular mil (cmil) is an Imperial / US customary unit of area. The mil is a unit of length in the Imperial and US customary systems of units. An area of 1.0 circular mil is the area of a circle that is 1.0 mil in diameter.

The conversion formula between square mils and circular mils:

Square Mils = π/4 × Circular Mils

The circular mil is used to specify the area of the cross section of a cable or wire. For example, a wire size of 200 kcmil or 200 MCM is a wire that has a cross-section of 200,000 circular mils.

*Note:*

1 MCM = 1 kcmil = 1,000 circular mils

Symbol: cmil

Plural: circular mils