Acres to Square Miles Calculator
Convert a land area in acres to square miles using the exact 640 acres-per-square-mile factor.
About the Acres to Square Miles Calculator
The acre and the square mile are both traditional units of land area used in the US and UK. A square mile is a much larger unit, historically equal to one "section" of land in the US Public Land Survey System used to divide the American Midwest into a grid, and it contains exactly 640 acres.
Formula: Square Miles = Acres ÷ 640
For example, a 640-acre section of farmland equals exactly 1 square mile, while a 1,000-acre ranch equals 1.5625 square miles, and a 10,000-acre property equals a little over 15.6 square miles.
This conversion is commonly used in agriculture, ranching, county land records and US land surveying, where large rural parcels are often described in both acres and square miles depending on the context and the size of the property.