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 kilometer (km²) equals one million square meters and is used to measure large land areas such as cities, national parks, and countries. Geographic data, urban planning reports, and ecological studies rely on square kilometers as their standard area unit. One square kilometer equals approximately 0.3861 square miles or about 247.1 acres.