Acres to Square Miles Converter
Type a value in acres to see it in square miles as you type, with the exact formula and a reference chart.
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How this was calculated
- 1 square mile = 640 acres
- 640 ÷ 640 = 1 mi²
| ac | mi² |
|---|---|
| 1 ac | 0.0015625 mi² |
| 10 ac | 0.015625 mi² |
| 40 ac | 0.0625 mi² |
| 80 ac | 0.125 mi² |
| 160 ac | 0.25 mi² |
| 320 ac | 0.5 mi² |
| 640 ac | 1 mi² |
| 1,000 ac | 1.5625 mi² |
| 1,280 ac | 2 mi² |
| 2,000 ac | 3.125 mi² |
| 5,000 ac | 7.8125 mi² |
| 10,000 ac | 15.625 mi² |
| 50,000 ac | 78.125 mi² |
| 100,000 ac | 156.25 mi² |
| mi² | ac |
|---|---|
| 0.001 mi² | 0.64 ac |
| 0.002 mi² | 1.28 ac |
| 0.005 mi² | 3.2 ac |
| 0.01 mi² | 6.4 ac |
| 0.02 mi² | 12.8 ac |
| 0.05 mi² | 32 ac |
| 0.1 mi² | 64 ac |
| 0.2 mi² | 128 ac |
| 0.5 mi² | 320 ac |
| 1 mi² | 640 ac |
| 2 mi² | 1,280 ac |
| 5 mi² | 3,200 ac |
How to convert acres to square miles
1 acre = 0.0015625 square miles. To convert acres to square miles, divide by 640 (or multiply by 0.0015625). An acre is 43,560 square feet, about 4,046.86 m². A square mile is a 1 mi × 1 mi square: 640 acres, about 2.59 km².
Worked examples
- 160 acres = 0.25 mi² (160 ÷ 640)
- 640 acres = 1 mi² (640 ÷ 640)
- 10,000 acres = 15.625 mi² (10,000 ÷ 640)
Where this conversion comes up
Acres are used for land, farm and lot sizes in the US and UK; square miles for city, county and state areas in the US and UK. A square mile is exactly 640 acres, so a quarter section (160 acres) is a quarter of a square mile and a 10,000-acre ranch is 15.6 square miles. US land surveys are laid out in 640-acre sections.
Quick estimate
Divide by 640.
Common mistakes
- Multiplying instead of dividing. A square mile is larger than a acre, so the number of square miles must come out smaller: 160 acres = 0.25 mi².
- Rounding too early. Keep the full factor until the last step; rounding 0.00156 to 0.0016 first puts large values noticeably off.
Related area converters: acres to square feet, hectares to acres, acres to hectares, square feet to square meters, square meters to square feet, square feet to acres.
Frequently asked questions
How do you convert acres to square miles?
Multiply the acres by 0.0015625 (or divide by 640). For example, 640 acres is 1 square miles.
How many square miles are in one acre?
One acre is 0.0015625 square miles. An acre is 43,560 square feet, about 4,046.86 m².
What is 10,000 acres in square miles?
10,000 acres is 15.625 square miles.
Is there a quick way to estimate acres to square miles?
Divide by 640.