Square Miles to Acres converter (mi² to ac)
Convert Square Miles (mi²) to Acres (ac) 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.
Acres to Square Miles (ac to mi²) ►
How to convert Square Miles to Acres
1 square mile (mi²) is equal to 640 acres.
ac = mi² × 640
Multiply the square miles by 640:
Example: Convert 2 mi² to acres:
ac = 2 × 640 = 1,280 ac
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.
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.
This page converts area from Square Miles into Acres. One mi² equals 640 ac.
Square Miles to Acres conversion table
Common mi² values and the matching ac result, calculated with the same factor as the widget. Highlight a nearby row if you want a quick check without entering a number.
| Square Miles (mi²) | Acres (ac) |
|---|---|
| 0.1 mi² | 64 ac |
| 0.5 mi² | 320 ac |
| 1 mi² | 640 ac |
| 2 mi² | 1280 ac |
| 5 mi² | 3200 ac |
| 10 mi² | 6400 ac |
| 50 mi² | 32000 ac |
| 100 mi² | 64000 ac |
How this calculator works
The form on this page is a Square Miles-to-Acres converter. After you enter a number, JavaScript multiplies or rearranges it with the published conversion factor and writes the ac 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 ac are in 1 mi²?
1 mi² = 640 ac.
How do I convert Square Miles to Acres?
Multiply the square miles by 640:
Is this mi² to ac 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.