Convert square miles to acres
Enter a square miles value below and convert to acres
mi²
1 square mile =
640 acres
* exact result
Select how many decimal places the result will be rounded to:
How to convert square miles to acres
To convert square miles to acres, multiply a square miles value by 640.
Formula ac = mi² × 640
Example: Convert 5 square miles to acres Calculations: 5 mi² × 640 = 3200 ac
Square mile (mi²)
The square mile is the imperial system's unit of area, defined as the area of a square with sides of 1 mile. It is equal to about 2.59 square kilometers.
Acre (ac)
The acre is the imperial system's unit of area, defined as the area of a rectangle with sides of 66 and 660 feet. It is equal to about 0.4047 hectares.