Convert Square Chains to Circular Mils
Convert Square Chains (ch²) to Circular Mils (cmil) instantly and accurately.
Conversion Formula
cmil = ch² × 798657329800
About Square Chains
A square chain (ch²) is a surveying unit equal to the area of a square with sides of one Gunter's chain (66 feet or ~20.12 m), approximately 404.69 m². Ten square chains equal exactly one acre, making it the natural subdivision unit in traditional land surveying. The US Public Land Survey System used chains to lay out townships and sections, and square chains appear throughout old legal property descriptions and government land grants across North America. One square chain equals exactly 16 square rods.
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 Chains (ch²) | Circular Mils (cmil) |
|---|---|
| 1 ch² | 7.987 × 1011 cmil |
| 2 ch² | 1.597 × 1012 cmil |
| 5 ch² | 3.993 × 1012 cmil |
| 10 ch² | 7.987 × 1012 cmil |
| 25 ch² | 1.997 × 1013 cmil |
| 50 ch² | 3.993 × 1013 cmil |
| 100 ch² | 7.987 × 1013 cmil |