Convert square miles to acres
1 mi² = 640 ac — exactly. Both units are defined against the SI, so this factor is a fraction, not an approximation.
640ac
1 mi² = 640 ac
How to convert square miles to acres
Multiply the number of square miles by 640 to get acres.
The exact factor is 640 .
Acre: Exactly 4840 square yards — historically a day of ploughing.
Square mile to Acre conversion table
| Square miles (mi²) | Acres (ac) |
|---|---|
| 1 mi² | 640 |
| 2 mi² | 1280 |
| 3 mi² | 1920 |
| 5 mi² | 3200 |
| 10 mi² | 6400 |
| 20 mi² | 12 800 |
| 25 mi² | 16 000 |
| 50 mi² | 32 000 |
| 100 mi² | 64 000 |
| 250 mi² | 160 000 |
| 500 mi² | 320 000 |
| 1000 mi² | 640 000 |
Acre to Square mile conversion table
| Acres (ac) | Square miles (mi²) |
|---|---|
| 1 ac | 0.001 562 5 |
| 2 ac | 0.003 125 |
| 3 ac | 0.004 687 5 |
| 5 ac | 0.007 812 5 |
| 10 ac | 0.015 625 |
| 20 ac | 0.031 25 |
| 25 ac | 0.039 062 5 |
| 50 ac | 0.078 125 |
| 100 ac | 0.156 25 |
| 250 ac | 0.390 625 |
| 500 ac | 0.781 25 |
| 1000 ac | 1.5625 |
Frequently asked
How many acres are in a square mile?
One square mile equals 640 acres (mi² → ac). That figure is exact, not rounded.
How do you convert square miles to acres?
Multiply the number of square miles by 640 to get acres.
What is 1 ac in square miles?
One acre is 0.0015625 square miles.
What is 10 mi² in ac?
10 mi² = 6400 ac.
What exactly is a acre?
Exactly 4840 square yards — historically a day of ploughing.