The square millimeter (mm²) is a metric unit of area equal to one-millionth of a square meter, used in precision engineering, microelectronics, and medical imaging. It is ideal for measuring the cross-sectional area of wires, the surface area of microchips, and other tiny surfaces. One square millimeter equals roughly 0.00155 square inches.

The square meter (m²) is the SI base unit of area, equal to a square measuring one meter on each side, used worldwide for real estate, construction, and land surveying. Apartment sizes, office floor plans, and construction costs are almost universally quoted in square meters outside the United States. One square meter equals approximately 10.764 square feet.