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.

The square foot (ft²) is an imperial area unit equal to a square measuring one foot on each side, the standard measurement for home sizes, office space, and rental properties in the United States. Real estate listings in America almost always quote living space in square feet, making it one of the most practically relevant area units. One square foot equals exactly 0.0929 square meters.