Convert acres to square miles
Select how many decimal places the result will be rounded to:
How to convert acres to square miles
To convert acres to square miles, divide a acres value by 640.
Formula mi² = ac ÷ 640
Example: Convert 100 acres to square miles Calculations: 100 ac ÷ 640 ≈ 0.1563 mi²
Acre (ac)
The acre is an imperial and US customary systems unit of area, defined as the area of a rectangle with sides of 66 and 660 feet. It is approximately equal to 0.4047 hectares.
Square mile (mi²)
The square mile is an imperial and US customary systems unit of area, defined as the area of a square with sides of 1 mile. It is approximately equal to 2.59 square kilometers.
Browse related converters
Acres to Square kilometers Acres to Square meters Acres to Square yards Acres to Square feet Acres to Square inches Acres to Hectares