Acre to Square Mile Converter (ac to mi²)

1 acre equals 0.0015625 square miles — multiply the number of acres by 0.0015625 to convert. Put the other way round, there are exactly 640 acres in one square mile.

The formula

To convert acres to square miles, multiply by 0.0015625:

square miles = acres × 0.0015625

For example, 10 ac × 0.0015625 = 0.015625 mi². To reverse it, divide by 0.0015625 (or multiply by 640).

Conversion table

How to convert online

1. Type the number of acres into the first box.
2. Read the square-mile value instantly in the second box.
3. Enter a mi² value to convert back to acres — it works both ways.

Use the Acre to Square Mile Converter — free and instant in your browser.

Where this conversion is used

Square miles describe large tracts — ranches, counties, watersheds and public land — while acres describe individual parcels. Converting is useful when aggregating many acre-sized holdings into a total area, or comparing a property against township and section boundaries in the US survey system.

FAQ

How many acres are in a square mile?

Exactly 640 acres. So one square mile is 640 acres, and 1000 acres is 1.5625 square miles.

How do I convert square miles back to acres?

Divide by 0.0015625, or multiply by 640. For example, 2 mi² is 1,280 acres.

Is the conversion exact?

Yes. Because 1 mi² is defined as exactly 640 acres, the factor 0.0015625 (which is 1/640) is exact.

Is this converter free and private?

Yes. It runs entirely in your browser — nothing is uploaded or stored. It is free, needs no sign-up and works offline once loaded.

Related converters

• Square Mile to Acre Converter
• Acre to Square Kilometer Converter
• Acre to Square Meter Converter
• Acre to Hectare Converter

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