Square Miles to Acres Converter
Enter the area in square miles below to get the value converted to acres.
Do you want to convert acres to square miles?
How to Convert Square Miles to Acres
To convert a measurement in square miles to a measurement in acres, multiply the area by the following conversion ratio: 640 acres/square mile.
Since one square mile is equal to 640 acres, you can use this simple formula to convert:
The area in acres is equal to the area in square miles multiplied by 640.

How Many Acres Are in a Square Mile?
There are 640 acres in a square mile, which is why we use this value in the formula above.
1 sq mi = 640 ac
Square miles and acres are both units used to measure area. Keep reading to learn more about each unit of measure.
What is a Square Mile?
One square mile is equal to the area of a square with sides that are each 1 mile long. One square mile is roughly equal to 2.59 square kilometers or 640 acres.
The square mile is a US customary and imperial unit of area. Square miles can be abbreviated as sq mi, and are also sometimes abbreviated as mi². For example, 1 square mile can be written as 1 sq mi or 1 mi².
Learn more about square miles.
What is an Acre?
One acre is defined as the area equal to a space that is one chain (66 ft) by one furlong (660 ft), or 10 square chains.[1] That's equal to 43,560 square feet or 1/640 of a square mile for those unfamiliar with those units of measure.

The acre is a US customary and imperial unit of area. Acres can be abbreviated as ac; for example, 1 acre can be written as 1 ac.
You can use an acreage calculator to measure the area of a plot of land in acres by locating the boundaries on a map.
Learn more about acres.
Square Mile to Acre Conversion Table
Square Miles | Acres |
---|---|
1 sq mi | 640 ac |
2 sq mi | 1,280 ac |
3 sq mi | 1,920 ac |
4 sq mi | 2,560 ac |
5 sq mi | 3,200 ac |
6 sq mi | 3,840 ac |
7 sq mi | 4,480 ac |
8 sq mi | 5,120 ac |
9 sq mi | 5,760 ac |
10 sq mi | 6,400 ac |
11 sq mi | 7,040 ac |
12 sq mi | 7,680 ac |
13 sq mi | 8,320 ac |
14 sq mi | 8,960 ac |
15 sq mi | 9,600 ac |
16 sq mi | 10,240 ac |
17 sq mi | 10,880 ac |
18 sq mi | 11,520 ac |
19 sq mi | 12,160 ac |
20 sq mi | 12,800 ac |
21 sq mi | 13,440 ac |
22 sq mi | 14,080 ac |
23 sq mi | 14,720 ac |
24 sq mi | 15,360 ac |
25 sq mi | 16,000 ac |
26 sq mi | 16,640 ac |
27 sq mi | 17,280 ac |
28 sq mi | 17,920 ac |
29 sq mi | 18,560 ac |
30 sq mi | 19,200 ac |
31 sq mi | 19,840 ac |
32 sq mi | 20,480 ac |
33 sq mi | 21,120 ac |
34 sq mi | 21,760 ac |
35 sq mi | 22,400 ac |
36 sq mi | 23,040 ac |
37 sq mi | 23,680 ac |
38 sq mi | 24,320 ac |
39 sq mi | 24,960 ac |
40 sq mi | 25,600 ac |
References
- National Institute of Standards and Technology, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, Handbook 44 - 2019 Edition, https://nvlpubs.nist.gov/nistpubs/hb/2019/NIST.HB.44-2019.pdf
More Square Mile & Acre Conversions
- square miles to square yards
- square miles to square feet
- square miles to square inches
- square miles to square kilometers
- square miles to square meters
- square miles to square centimeters
- square miles to square millimeters
- square miles to hectares
- square miles to ares
- square yards to acres
- square feet to acres
- square inches to acres
- square kilometers to acres
- square meters to acres
- square centimeters to acres
- square millimeters to acres
- hectares to acres
- ares to acres