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Area
Acres to Square miles
Convert acres (ac) to square miles (mi²). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 ac = 0.001563 mi²
Acres to Square miles Conversion Table
Common values, ready to copy:
| acres | square miles |
|---|---|
| 1 ac | 0.001563 mi² |
| 2 ac | 0.003125 mi² |
| 5 ac | 0.007813 mi² |
| 10 ac | 0.015625 mi² |
| 25 ac | 0.039063 mi² |
| 50 ac | 0.078125 mi² |
| 100 ac | 0.15625 mi² |
| 1,000 ac | 1.5625 mi² |
Formula
square miles = acres × 1.56250138e-3
Area conversions are derived from length: 1 ft² = (0.3048 m)² = 0.092903 m². 1 acre = 4,046.86 m². 1 hectare = 10,000 m² exactly.
About Acres and Square miles
Acres (ac): An old English unit, originally the area a yoke of oxen could plow in a day; standardized at exactly 4,046.86 m² (43,560 sq ft). Common uses: Land area in the US, UK, and most former British colonies — farm sizes, residential lots, and ranch acreage.
Square miles (mi²): One mile squared, or 2.59 km²; the standard US unit for large land areas. Common uses: City and county area, state and national park sizes, watersheds, and large geographic features in the US.
How the conversion works
Area conversions are derived from length: 1 ft² = (0.3048 m)² = 0.092903 m². 1 acre = 4,046.86 m². 1 hectare = 10,000 m² exactly.
The exact relationship is square miles = acres × 1.56250138e-3, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between acres and square miles comes up wherever area measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.