Convert Square Rod (US Survey) (rod² (US)) to Circular Mil (circ mil) instantly.
About these units
Square Rod (US Survey) (rod² (US))
The US survey square rod is defined using the survey foot and differs negligibly from the international square rod. This distinction matters in legal contexts, especially when interpreting older property descriptions dating back to the 19th-century PLSS-era surveys. The unit persists primarily in legal documents and rural land records, ensuring that historical boundaries remain consistent even as measurement standards evolve.
Circular Mil (circ mil)
A circular mil is defined as the area of a circle with a diameter of exactly one mil. Because wires and cables have circular cross-sections, the circular mil has become a standard unit in electrical engineering for specifying conductor sizes. One circular mil simplifies calculations because area scales directly with the square of wire diameter without needing π in computations. For example, doubling a wire's diameter increases its circular-mil area fourfold. This makes circular mils extremely convenient for determining ampacity, resistance, and voltage drop in electrical conductors. Even though SI units are common elsewhere, the circular mil remains entrenched in North American electrical codes.