Convert Square Mil (mil²) to Square Inch (in²) instantly.
About these units
Square Mil (mil²)
A square mil equals the area of a square one mil (0.001 inch) on each side, producing an area of one-millionth of a square inch. This tiny unit appears in microfabrication, thin-film manufacturing, and fine electronic component design. Engineers rely on mils and mil² for PCB trace design, wire bonding pads, and micro-mechanical parts. Despite modern efforts to shift toward metric units, mils remain deeply embedded in American electronics manufacturing due to legacy tooling and engineering standards.
Square Inch (in²)
A square inch represents the area of a one-inch by one-inch square. It is indispensable in engineering, manufacturing, machine design, and consumer product specifications. Mechanical components, gasket areas, electronic device screens, and pipe cross-sections are often measured in square inches. Because imperial units are deeply rooted in American manufacturing, the square inch enables precise communication among engineers and technicians. The unit remains important in pressure measurement as well—psi (pounds per square inch) combines force and area into one of the most widely recognized engineering units worldwide.