Square miles to acres
One square mile is exactly 640 acres. Multiply square miles by 640, or type a number in either box.
Exact factor: 1 square mile = 640 acres.
The formula
Acres = square miles × 640.
Quick reference
| Square miles | Acres |
|---|---|
| 0.25 | 160 |
| 0.5 | 320 |
| 1 | 640 |
| 2 | 1,280 |
| 5 | 3,200 |
| 10 | 6,400 |
| 100 | 64,000 |
Sections and quarter sections
Much of the United States was surveyed into sections of one square mile, or 640 acres. A quarter section is 160 acres, and a quarter of that is 40 acres, which is where “the back forty” comes from. North Carolina was settled before that system and uses older metes-and-bounds descriptions, so its parcels rarely fall on neat section lines.
Reading large tracts
A one-mile by one-mile square is 640 acres. A campus-scale tract of a few hundred acres is a sizable share of a square mile. When tracts reach that size, the question shifts from how much land to how much of it can be used. See the usable acreage calculator.
Questions
How many acres are in a square mile?
There are exactly 640 acres in one square mile.
How many acres is a quarter of a square mile?
A quarter of a square mile is 160 acres.
How many square miles is 1,000 acres?
One thousand acres is about 1.56 square miles.
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