Convert Square Miles to Acres
One square mile equals 640 acres. Type any value to convert square miles to acres instantly — with a full reference table below.
Convert Square Miles to Acres
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How to convert Square Miles to Acres
To convert square miles to acres, multiply by 640. One square mile equals 640 ac, and one acre equals 0.0015625 mi².
- Take the value in square miles — for example 7.5 mi².
- Multiply by 640 (the number of acres in one square mile).
- 7.5 × 640 = 4,800 ac.
Quick mental estimate: Multiply the number of square miles by 640 — that is exact.
Square Miles to Acres conversion table
| Square Miles | Acres |
|---|---|
| 1 mi² | 640 ac |
| 2 mi² | 1,280 ac |
| 3 mi² | 1,920 ac |
| 5 mi² | 3,200 ac |
| 10 mi² | 6,400 ac |
| 20 mi² | 12,800 ac |
| 50 mi² | 32,000 ac |
| 100 mi² | 64,000 ac |
| 200 mi² | 128,000 ac |
| 500 mi² | 320,000 ac |
| 1,000 mi² | 640,000 ac |
| 5,000 mi² | 3,200,000 ac |
| Acres | Square Miles |
|---|---|
| 1 ac | 0.0015625 mi² |
| 2 ac | 0.003125 mi² |
| 3 ac | 0.0046875 mi² |
| 5 ac | 0.0078125 mi² |
| 10 ac | 0.015625 mi² |
| 20 ac | 0.03125 mi² |
| 50 ac | 0.078125 mi² |
| 100 ac | 0.15625 mi² |
| 200 ac | 0.3125 mi² |
| 500 ac | 0.78125 mi² |
| 1,000 ac | 1.5625 mi² |
| 5,000 ac | 7.8125 mi² |
About converting Square Miles to Acres
Square Miles (mi²) and Acres (ac) are both units of area. The exact factor is 1 mi² = 640 ac, so multiply by 640 to go from square miles to acres (or divide to go back).
The conversion runs entirely in your browser. Need the reverse? Use the Acres to Square Miles converter, or the full unit converter for every unit at once.
Real-world area in square miles and acres
| Example | Square Miles | Acres |
|---|---|---|
| A doubles tennis court (23.77 × 10.97 m) | 0.000100679 mi² | 0.0644344 ac |
| An NBA basketball court (94 × 50 ft) | 0.000168589 mi² | 0.107897 ac |
| An American football field (incl. end zones) | 0.00206612 mi² | 1.322314 ac |
| A football pitch (105 × 68 m) | 0.00275677 mi² | 1.764332 ac |
| One acre | 0.0015625 mi² | 1 ac |
“≈” marks typical values; the rest are defined or measured figures.
The units
A square 1 mile on each side: 640 acres, about 2.59 km².
Used for: US/UK land and city areas.
43,560 square feet, exactly 4,046.8564224 m².
Used for: Farmland and property in the US, UK, India and Australia.
Area factors are the squares of exact length factors, so they are exact too (an international acre is exactly 4,046.8564224 m²).