Convert Square miles to acres
1 square mile = 640 acres · ac = mi² × 640
When you need this conversion
This conversion goes from square miles, used for US counties, states, and large regions, to acres, the land measure used in the US and UK. Both measure the same physical quantity, so the conversion is exact — the difference is which unit your source, tool, or region happens to use.
Square miles to acres conversion table
| Square miles (mi²) | Acres (ac) |
|---|---|
| 1 mi² | 640 ac |
| 2 mi² | 1,280 ac |
| 3 mi² | 1,920 ac |
| 5 mi² | 3,200 ac |
| 10 mi² | 6,400 ac |
| 15 mi² | 9,600 ac |
| 20 mi² | 12,800 ac |
| 25 mi² | 16,000 ac |
| 50 mi² | 32,000 ac |
| 75 mi² | 48,000 ac |
| 100 mi² | 64,000 ac |
| 250 mi² | 160,000 ac |
| 500 mi² | 320,000 ac |
| 1,000 mi² | 640,000 ac |
The formula
ac = mi² × 640Because both units measure area, the conversion is a single multiplication by a fixed factor. That factor never changes, so the result is exact.
Convert the other way
Acres to square miles →Related area conversions
- Hectares to acres
- Square meters to square feet
- Square feet to square meters
- Acres to hectares
- Square millimeters to acres
- Square centimeters to acres
- Square meters to acres
- Square kilometers to acres
- Square inches to acres
- Square feet to acres
- Square yards to acres
- Square miles to square millimeters
Frequently asked questions
- How many acres are in a square mile?
- There are 640 acres in 1 square mile. The formula is ac = mi² × 640.
- How do you convert square miles to acres?
- Use the formula ac = mi² × 640. For example, 10 square miles equals 6,400 acres.
- Is the square miles to acres conversion exact?
- Yes. Square miles and acres are both units of area, related by an exact defined factor. Displayed results are rounded for readability.
- What is mi² short for?
- mi² is the standard symbol for square mile. ac is the symbol for acre.