Acre to Square Kilometer Converter

An acre (ac) is a unit of area traditionally defined as the amount of land a yoke of oxen could plow in one day. It equals 43,560 square feet or approximately 4,047 square meters, making it ideal for measuring agricultural and residential land.

The acre originated in medieval England around the 13th century, derived from the Old English 'æcer' meaning 'field'. It was originally defined as a furlong (660 feet) long by one chain (66 feet) wide, representing a practical day's work for a farmer. The acre was standardized in various forms across different regions before being internationally defined.

Acres are extensively used in the United States, United Kingdom, Canada, and other Commonwealth countries for measuring farmland, residential properties, and real estate. They're standard in agricultural reports, property listings, land development, and zoning regulations in these countries.

A square kilometer (km²) is a unit of area equal to the area of a square with sides of one kilometer each. It equals 1,000,000 square meters or 100 hectares, making it suitable for measuring large geographical areas.

The square kilometer emerged naturally from the metric system established during the French Revolution in 1795. As the kilometer became standardized for distance measurement, its square became the logical unit for large area measurements, particularly useful for mapping territories and countries.

Square kilometers are universally used for measuring countries, states, cities, large properties, national parks, and geographical features. They're standard in atlases, geographic surveys, urban planning, and environmental studies. Most countries report their total area in square kilometers.