Table Of Contents
Square miles to acres Conversion
1 square miles (mi²) is equal to 640 acres (acre).
1 mi² = 640 acre
or
1 acre = 0.0015625 mi²
Formula
To convert a area from square miles (mi²) to acres (acre), multiply the area in square miles by 640
a(acre) = a(mi²) × 640
Examples:
Convert 1 square miles to acres:
a(acre) = 1mi² × 640 = 640 acre
Conversion table
| Square miles (mi²) | Acres (acre) |
|---|---|
| 1 mi² | 640 acre |
| 2 mi² | 1280 acre |
| 3 mi² | 1920 acre |
| 5 mi² | 3200 acre |
| 10 mi² | 6400 acre |
| 20 mi² | 12800 acre |
| 25 mi² | 16000 acre |
| 50 mi² | 32000 acre |
| 100 mi² | 64000 acre |
| 250 mi² | 160000 acre |
| 500 mi² | 320000 acre |
| 1000 mi² | 640000 acre |
| Acres (acre) | Square miles (mi²) |
|---|---|
| 1 acre | 0.0015625 mi² |
| 2 acre | 0.003125 mi² |
| 3 acre | 0.0046875 mi² |
| 5 acre | 0.0078125 mi² |
| 10 acre | 0.015625 mi² |
| 20 acre | 0.03125 mi² |
| 25 acre | 0.0390625 mi² |
| 50 acre | 0.078125 mi² |
| 100 acre | 0.15625 mi² |
| 250 acre | 0.390625 mi² |
| 500 acre | 0.78125 mi² |
| 1000 acre | 1.5625 mi² |
Frequently asked questions
How do I convert square miles to acres?
Multiply the value in square miles by 640 to get the result in acres. For example, 5 mi² × 640 = 3200 acre.
How many acres are in 1 square miles?
1 square miles (mi²) is equal to 640 acres (acre).
How do I convert acres back to square miles?
Use the inverse operation: divide the value in acres by 640 to get the result in square miles.
How accurate is the square miles to acres conversion?
The converter multiplies by the conversion factor 640 and rounds the result to 9 decimal places by default. You can increase or reduce the precision with the digits option on this page.
Sources
Conversion factors are based on internationally recognised standards:
- BIPM — The International System of Units (SI Brochure, 9th edition)
- NIST Handbook 44, Appendix C — General Tables of Units of Measurement (current edition)
- U.S. Survey Foot: Revised Unit Conversion Factors
- NIST Guide to the SI (SP 811), Appendix B.9: Factors for units listed by kind of quantity or field of science
