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# Convert acres to square miles

Please provide values below to convert acre [ac] to square mile [mi^2], or vice versa.

 From: acre To: square mile

### Acre

Definition: An acre (symbol: ac) is a unit of land area used in the imperial and US customary systems. It is defined as the area of 1 chain (66 feet) by 1 furlong (660 feet), which is exactly equal to 1/640 of a square mile, 43,560 square feet, or exactly 4046.8564224 square meters.

History/origin: In the Middle Ages, the acre was defined as the area that a yoke (pair) of oxen could typically plow within one day, using a wooden plow. Before the metric system was adopted, many countries used their own versions of the acre. The most commonly used acre today, the international acre, is based on the international yard, which was defined in 1959.

Current use: Acres are used in countries including the United States, the UK, Ghana, India, Canada, and others. The United States (US) uses both international as well as US survey acres (~4047 square meters), which vary based on which type of yard is used in the measurement. However, area measurements are typically not accurate enough for the difference between the two acre measurements to be detectable.

### Square mile

Definition: The square mile (symbol: sq mi or mi2) is a unit of area in the imperial and United States customary (UCS) systems of units. It is defined as the area of a square with side lengths of one statute mile (5,280 feet). A square mile is a large area that is equal to 27,878,400 square feet, 3,097,600 square yards, and 640 acres.

History/origin: Area is commonly represented in the form of a square with sides of a specific unit of length, written as "square" followed by the chosen unit of length. The square mile is one of many such units and is derived from the area of a square with sides of one mile.

Current use: Square miles are used when the measurement involves large scales such as country sizes. It can be used when referencing population studies, such as a measurement of total population per square mile. As an imperial and USC unit, it is most commonly used in countries that use these systems of measurement. In countries that have adopted the International System of Units, the square meter (and its subsequent multiples and submultiples) is the preferred system of measurement.

### Acre to Square Mile Conversion Table

Acre [ac]Square Mile [mi^2]
0.01 ac1.5625E-5 mi^2
0.1 ac0.00015625 mi^2
1 ac0.0015625 mi^2
2 ac0.003125 mi^2
3 ac0.0046875 mi^2
5 ac0.0078125 mi^2
10 ac0.015625 mi^2
20 ac0.03125 mi^2
50 ac0.078125 mi^2
100 ac0.15625 mi^2
1000 ac1.5625 mi^2

### How to Convert Acre to Square Mile

1 ac = 0.0015625 mi^2
1 mi^2 = 640 ac

Example: convert 15 ac to mi^2:
15 ac = 15 × 0.0015625 mi^2 = 0.0234375 mi^2