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.

The square inch (in²) is a small imperial area unit equal to a square measuring one inch on each side, commonly used in engineering specifications, screen size descriptions, and pressure measurements. Piston areas, material stress calculations, and electronic component sizes are frequently expressed in square inches. One square inch equals exactly 6.4516 square centimeters.