sq miles to acres Converter
Convert sq miles to acres instantly: 1 sq miles = 640 acres. Free converter with the formula, a reference table and FAQs — no sign-up.
| sq miles | acres |
|---|
How to convert sq miles to acres
Enter your value
Type the number of sq miles you want to convert into the left box. The result in acres appears instantly in the right box. You can also type into the right box to convert in the other direction.
Use the swap button
Click the ⇄ Swap button to reverse the conversion — acres to sq miles. Your current value carries across so you don't have to re-enter anything.
About sq miles and acres
sq miles and acres are both area measurements.
Worked examples: sq miles to acres
Multiply the sq miles value by 640 to get acres. A few quick examples:
- 5 sq miles × 640 = 3,200 acres
- 25 sq miles × 640 = 16,000 acres
- 250 sq miles × 640 = 160,000 acres
Related conversions
1 sq mile = 640 acres. US land in the Midwest was surveyed using the Public Land Survey System — 'townships' (6 sq miles = 3,840 acres) divided into 36 'sections' (1 sq mile = 640 acres), then half-sections, quarter-sections, and 40-acre 'forties'. Many US farm sizes are multiples of 40 acres.
| sq miles | acres |
|---|---|
| 0.01 | 6.4 |
| 0.1 | 64 |
| 0.5 | 320 |
| 1 | 640 |
| 2 | 1280 |
| 5 | 3200 |
Frequently asked questions
How do I convert sq miles to acres?
To convert sq miles to acres, multiply by 640. Or use the calculator above for instant results.
How many acres are in 1 sq miles?
1 sq miles equals 640 acres.
Is the sq miles to acres converter free?
Yes, the sq miles to acres converter is completely free with no sign-up required, no downloads, and it works offline once the page has loaded.