How do I convert acres to square miles?

Multiply the acre value by 0.0015625. So x ac × 0.0015625 = the equivalent in mi².

What is 5 acres in square miles?

5 acres equals 0.0078125 square miles.

What is 10 acres in square miles?

10 acres equals 0.015625 square miles.

What is 100 acres in square miles?

100 acres equals 0.15625 square miles.

How do I convert back from square miles to acres?

Multiply the square mile value by 640. For example, 1 mi² = 640 ac.

Is the acre bigger than the square mile?

No. 1 acre is smaller than 1 square mile. It takes 640 acres to equal 1 square mile.

Are these conversion factors exact?

Yes. Since the 1959 international yard and pound agreement, imperial/US units are defined exactly in terms of metric units, so the factor used here (0.0015625) is exact within IEEE 754 double precision.

Acres to Square miles Converter

1 ac = 0.0015625 mi² (acre → square mile)

1 ac = 0.0015625 mi²

1 acre equals 0.0015625 square miles. To convert acres to square miles, multiply the acre value by 0.0015625. For quick reference: 1 ac = 0.0015625 mi², 5 ac = 0.0078125 mi², 10 ac = 0.015625 mi², 100 ac = 0.15625 mi².

From

0.0015625

FormulaSquare miles = Acres × 0.0015625

Quick

When to use acres → square miles

Acres to square miles divides by 640 — exact, since the square mile was defined as 640 acres in the same survey system. A 160-acre 'quarter section' homestead is exactly 0.25 sq mi. The 640 figure is the backbone of US public-land geography: sections, quarter-sections, and quarter-quarter (40-acre) parcels all divide evenly out of the square mile, which is why so many US land descriptions come in multiples of 40 acres.

How to convert acres to square miles

Take your value
Start with your value in acres.
Multiply by 0.0015625
Multiply the acre value by 0.0015625. This is the exact conversion factor from acres to square miles.
Read the result
The product is your value in square miles. For example, 5 ac × 0.0015625 = 0.0078125 mi².

Conversion formula

The exact factor from acres to square miles is 0.0015625.

Square miles = Acres × 0.0015625

Acres to Square miles conversion table

Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.

Conversion table from acres to square miles
Acres (ac)	Square miles (mi²)
0.1 ac	0.00015625 mi²
0.25 ac	0.00039063 mi²
0.5 ac	0.00078125 mi²
1 ac	0.0015625 mi²
2 ac	0.003125 mi²
3 ac	0.0046875 mi²
4 ac	0.00625 mi²
5 ac	0.0078125 mi²
6 ac	0.009375 mi²
7 ac	0.010938 mi²
8 ac	0.0125 mi²
9 ac	0.014063 mi²
10 ac	0.015625 mi²
12 ac	0.01875 mi²
15 ac	0.023438 mi²
20 ac	0.03125 mi²
25 ac	0.039063 mi²
30 ac	0.046875 mi²
40 ac	0.0625 mi²
50 ac	0.078125 mi²
60 ac	0.09375 mi²
70 ac	0.10938 mi²
75 ac	0.11719 mi²
80 ac	0.125 mi²
90 ac	0.14063 mi²
100 ac	0.15625 mi²
120 ac	0.1875 mi²
150 ac	0.23438 mi²
200 ac	0.3125 mi²
250 ac	0.39063 mi²
300 ac	0.46875 mi²
400 ac	0.625 mi²
500 ac	0.78125 mi²
600 ac	0.9375 mi²
750 ac	1.1719 mi²
800 ac	1.25 mi²
1000 ac	1.5625 mi²
1200 ac	1.875 mi²
1500 ac	2.3438 mi²
2000 ac	3.125 mi²
2500 ac	3.9063 mi²
3000 ac	4.6875 mi²
4000 ac	6.25 mi²
5000 ac	7.8125 mi²
7500 ac	11.719 mi²
10000 ac	15.625 mi²
20000 ac	31.25 mi²
50000 ac	78.125 mi²
100000 ac	156.25 mi²
1000000 ac	1562.5 mi²

Real-world reference

An American football field (with end zones) is about 1.32 acres. A quarter-acre lot is the classic US suburban plot size.

Frequently asked questions

How many square miles are in 1 acre?: 1 acre equals 0.0015625 square miles.
How do I convert acres to square miles?: Multiply the acre value by 0.0015625. So x ac × 0.0015625 = the equivalent in mi².
What is 5 acres in square miles?: 5 acres equals 0.0078125 square miles.
What is 10 acres in square miles?: 10 acres equals 0.015625 square miles.
What is 100 acres in square miles?: 100 acres equals 0.15625 square miles.
How do I convert back from square miles to acres?: Multiply the square mile value by 640. For example, 1 mi² = 640 ac.
Is the acre bigger than the square mile?: No. 1 acre is smaller than 1 square mile. It takes 640 acres to equal 1 square mile.
Are these conversion factors exact?: Yes. Since the 1959 international yard and pound agreement, imperial/US units are defined exactly in terms of metric units, so the factor used here (0.0015625) is exact within IEEE 754 double precision.

About the acre and the square mile

The acre

The acre is the traditional imperial unit for land, still the standard for US and UK property, farmland, and parkland. One acre is exactly 4,046.8564224 m² — historically the area a yoke of oxen could plough in a day, standardised as 1 chain by 1 furlong (66 × 660 feet, or 43,560 square feet). An American football field including end zones is about 1.32 acres.

The square mile

The square mile is the imperial unit for large land areas, standard in US geography and census data. One square mile is exactly 2.589988110336 km² (1.609344 km squared), or 640 acres — the basis of the US Public Land Survey System's square-mile 'sections'. Los Angeles covers about 469 square miles.

Square miles to Acres

mi² → ac

Square meters to Square feet

m² → ft²

Square meters to Acres

m² → ac

Square meters to Hectares

m² → ha

Square meters to Square kilometers

m² → km²

Square meters to Square miles

m² → mi²