Acres to Square Miles converter (ac to mi²)
Convert Acres (ac) to Square Miles (mi²) with this free calculator. Type a value, press Convert, and the page applies the same factor shown in the formula below — no rounded shortcut, and nothing is stored on a server.
Square Miles to Acres (mi² to ac) ►
How to convert Acres to Square Miles
1 square mile (mi²) is equal to 640 acres.
mi² = ac ÷ 640
Multiply the acres by 0.0015625:
Example: Convert 640 acres to mi²:
mi² = 640 ÷ 640 = 1 mi²
What is a Acres?
The Acres (ac) is the starting or target unit on this page. Use the calculator above to convert values without looking up the factor by hand.
What is a Square Miles?
The Square Miles (mi²) is the starting or target unit on this page. Use the calculator above to convert values without looking up the factor by hand.
This page converts area from Acres into Square Miles. One ac equals 0.0015625 mi².
Acres to Square Miles conversion table
Common ac values and the matching mi² result, calculated with the same factor as the widget. Highlight a nearby row if you want a quick check without entering a number.
| Acres (ac) | Square Miles (mi²) |
|---|---|
| 100 ac | 0.15625 mi² |
| 200 ac | 0.3125 mi² |
| 500 ac | 0.78125 mi² |
| 640 ac | 1 mi² |
| 1000 ac | 1.5625 mi² |
| 5000 ac | 7.8125 mi² |
| 10000 ac | 15.625 mi² |
How this calculator works
The form on this page is a Acres-to-Square Miles converter. After you enter a number, JavaScript multiplies or rearranges it with the published conversion factor and writes the mi² result in the output box. The step-by-step panel repeats the arithmetic so you can copy it into homework or a spreadsheet.
Reviewed by Hamsen, founder of GigaTables and a biology engineer. See the about page for how formulas are checked before a tool is published.
FAQ
How many mi² are in 1 ac?
1 ac = 0.0015625 mi².
How do I convert Acres to Square Miles?
Multiply the acres by 0.0015625:
Is this ac to mi² converter free?
Yes. GigaTables calculators are free to use in a browser. You do not need an account, and the values you type are not uploaded.