Convert Square Millimeters to Circular Mils
Convert Square Millimeters (mm²) to Circular Mils (cmil) instantly and accurately.
Conversion Formula
cmil = mm² × 1973.525241
About Square Millimeters
A square millimeter (mm²) is a metric unit of area equal to a square with sides of one millimeter. It is commonly used in precision engineering, electronics, and measuring very small surfaces such as microchips or printed circuit boards. To visualise: a typical pinhead has an area of about 2-3 mm². This unit is essential in microscopy, medical imaging, and manufacturing where tiny, precise measurements are critical.
About Circular Mils
A circular mil (cmil) is a unit used in electrical engineering to specify the cross-sectional area of round wires and cables. Equal to the area of a circle with a diameter of exactly one thou (one thousandth of an inch) - approximately 5.067 × 10⁻¹⁰ m² - it simplifies wire calculations: the cross-sectional area in cmil equals the wire diameter in mils, squared. US electrical codes (NEC/NEMA) specify conductor sizes in circular mils, and large cables are rated in thousands of circular mils (kcmil or MCM). A 12 AWG wire, common in US household wiring, has a cross-section of 6,530 cmil.
Quick Reference Table
| Square Millimeters (mm²) | Circular Mils (cmil) |
|---|---|
| 1 mm² | 1973.53 cmil |
| 2 mm² | 3947.05 cmil |
| 5 mm² | 9867.63 cmil |
| 10 mm² | 19735.3 cmil |
| 25 mm² | 49338.1 cmil |
| 50 mm² | 98676.3 cmil |
| 100 mm² | 197353 cmil |