Convert square miles to acres

1 mi²=640ac

Use the converter below to change any square miles value into acres instantly — with formula, conversion table, and real-world examples.

You have

Equals

640

Conversion formula

Forward

acres = square miles × 640

Reverse

square miles = acres × 0.001563

Example: 10 mi² × 640 = 6,400 ac.

About both units

From

Square Mile

mi²

The square mile equals 2.589988 square kilometres. It is used for US and UK geographic areas — city, county, state and country sizes. Greater London is 607 mi²; the US state of Texas is 268,597 mi².

Real-world: New York City is 302.6 mi². Texas is 268,597 mi². Greater London is 607 mi².

Read full square mile reference →

Acre

The acre equals 4046.86 square metres — originally the area a team of oxen could plough in a day. It is the standard rural land unit in the US, UK and Canada. Suburban American lots are typically a quarter to half an acre. 640 acres equal one square mile.

Real-world: A US suburban lot is 0.25–0.5 acre. A standard UK rural property might be 5 acres. A football pitch is about 1.8 acres.

Read full acre reference →

Square Mile to Acre conversion table

Common square miles to acres values for quick reference.

Square Mile (mi²)	Acre (ac)
1 mi²	640 ac
5 mi²	3,200 ac
10 mi²	6,400 ac
50 mi²	32,000 ac
100 mi²	64,000 ac
500 mi²	320,000 ac
1,000 mi²	640,000 ac
5,000 mi²	3,200,000 ac
10,000 mi²	6,400,000 ac
50,000 mi²	32,000,000 ac

Tips & common mistakes

Quick tips

1 mi² = 2.59 km² = 640 acres.
US land survey "section" = 1 mi²; "township" = 36 mi².
Common in US geography; replaced by km² in most of world.

Avoid these

Confusing square miles with statute miles (length).
Using 2.5 km² shortcut — correct 2.59 km² differs by 3.5%.
Mixing nautical square miles (irregular) with statute square miles.

Frequently asked questions

How many acres in a square mile?

One square mile equals 640 acres.

How do I convert square miles to acres?

Multiply the square mile value by 640 to get the equivalent in acres.

What is 100 square miles in acres?

100 square miles equals 64,000 acres.

Is a square mile bigger than a acre?

Yes. 1 square mile equals 640 acres, so one square mile is larger.

How to convert square miles to acres without a calculator?

Multiply by 640 for a quick estimate; use a calculator for precise results.

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