Formula
mi² to ac conversion formula
Use this relationship for a direct conversion:
ac = mi² x 640
Worked example
2 mi² = 1,280 ac.
Values derived from exact metric and international length definitions.
Area conversion
Convert Square mile to Acre
1 square mile (mi²) equals 640 acre (ac). Enter any value below to convert from mi² to ac.
Enter a value and choose units. Results update instantly.
1 mi² = 640 ac
All Area units
From 1 mi²| Unit | Value |
|---|---|
| Square meter m² | 2,589,988.1103360001 |
| Square kilometer km² | 2.5899881103 |
| Square centimeter cm² | 25,899,881,103.3600006104 |
| Square millimeter mm² | 2.5899881103e12 |
| Square inch in² | 4,014,489,600.0000004768 |
| Square foot ft² | 27,878,400 |
| Square yard yd² | 3,097,600 |
| Square mile mi² | 1 |
| Acre ac | 640 |
| Hectare ha | 258.9988110336 |
Recent conversions
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Quick reference
Square mile to Acre table
| Square mile (mi²) | Acre (ac) |
|---|---|
| 0.01 | 6.4 |
| 0.1 | 64 |
| 1 | 640 |
| 2 | 1,280 |
| 5 | 3,200 |
| 10 | 6,400 |
| 25 | 16,000 |
| 50 | 32,000 |
| 100 | 64,000 |
| 1,000 | 640,000 |
From unit
About the square mile
The area of a square one mile on each side.
Symbol: mi²
To unit
About the acre
Exactly 43,560 square feet.
Symbol: ac
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Source
Conversion standard
Definitions are checked against NIST SP 811: Area units. Calculations use full internal precision before display rounding.
View the complete area converterQuestions
mi² to ac FAQ
How do you convert square mile to acre?
Use the formula ac = mi² x 640. 1 square mile (mi²) equals 640 acre (ac).
Is the mi² to ac conversion exact?
Both unit definitions use exact factors. Only the displayed decimal may be rounded.