Convert Acres to square miles
1 acre = 0.0015625 square miles · mi² = ac ÷ 640
When you need this conversion
This conversion goes from acres, the land measure used in the US and UK, to square miles, used for US counties, states, and large regions. Both measure the same physical quantity, so the conversion is exact — the difference is which unit your source, tool, or region happens to use.
Acres to square miles conversion table
| Acres (ac) | Square miles (mi²) |
|---|---|
| 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 |
| 15 ac | 0.023438 mi² |
| 20 ac | 0.03125 mi² |
| 25 ac | 0.039063 mi² |
| 50 ac | 0.078125 mi² |
| 75 ac | 0.117188 mi² |
| 100 ac | 0.15625 mi² |
| 250 ac | 0.390625 mi² |
| 500 ac | 0.78125 mi² |
| 1,000 ac | 1.5625 mi² |
The formula
mi² = ac ÷ 640Because both units measure area, the conversion is a single multiplication by a fixed factor. That factor never changes, so the result is exact.
Convert the other way
Square miles to acres →Related area conversions
- Acres to hectares
- Square meters to square feet
- Square feet to square meters
- Hectares to acres
- Square millimeters to square miles
- Square centimeters to square miles
- Square meters to square miles
- Square kilometers to square miles
- Square inches to square miles
- Square feet to square miles
- Square yards to square miles
- Acres to square millimeters
Frequently asked questions
- How many square miles are in a acre?
- There are 0.0015625 square miles in 1 acre. The formula is mi² = ac ÷ 640.
- How do you convert acres to square miles?
- Use the formula mi² = ac ÷ 640. For example, 10 acres equals 0.015625 square miles.
- Is the acres to square miles conversion exact?
- Yes. Acres and square miles are both units of area, related by an exact defined factor. Displayed results are rounded for readability.
- What is ac short for?
- ac is the standard symbol for acre. mi² is the symbol for square mile.