Convert Square Millimeter (mm²) to Square Chain (ch²) instantly.
About these units
Square Millimeter (mm²)
A square millimeter represents the area of a square measuring 1 millimeter on each side. It is a tiny unit used extensively in engineering, electronics, material science, and medical instrumentation. Mechanical designers use mm² to determine cross-sectional areas of wires, beams, micro-mechanical parts, and precision components. In electronics, PCB traces, microchips, and sensors often specify dimensions in mm² for clarity and precision. Biomedical sciences also use mm² for cell colony measurements, tissue sample surfaces, and microscopic fields of view. Its size makes it ideal for quantifying structures too small for cm² but too large for micrometer-scale units.
Square Chain (ch²)
A square chain equals the area of a square one chain (~66 feet) per side, resulting in 4,356 square feet, or exactly 1/10 of an acre. This unit is closely linked to the chain, a surveyor's unit standardized by Edmund Gunter in the 17th century. Because 10 square chains make an acre, survey calculations for early colonial and American lands were extremely efficient. Square chains allowed surveyors to map and divide land rapidly using ropes or metal chains, producing a legacy seen in long, straight property lines still visible today across rural landscapes.