How to Convert Acres to Square Miles

Co-authored by wikiHow Staff

Last Updated: March 29, 2019 References

An acre is an area measurement that was originally defined by how much land an ox could plough in one day.^{[1]
X
Research source} Today the definition of an acre is standardized, so that it is easy to convert between acres and other units used to measure area, such as square miles (mi²). The Internet has numerous calculators that will make this conversion for you, but most teachers will require you to show your work, or you may be looking for an explanation of the actual steps involved. Luckily it is easy to calculate the conversion yourself using division or multiplication.

Method 1

Method 1 of 2:

Using Division

1
Understand that there are 640 acres in one square mile.^{[2]
X
Research source} Both units are different ways to measure area.
- By definition a square miles is square, but an acre can be any shape.^{[3]
  X
  Research source}
2
Determine how many acres you are converting to square miles. This number will probably already be given to you, but you can also use an area calculator map to determine the acreage of a real-world tract of land.^{[4]
X
Research source}
- For example, you might want to convert 2,500 acres to square miles.
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3
Divide the number of acres by 640.^{[5]
X
Research source} Each 640 acres equals 1 square mile, so you need to determine how many times 640 goes into the number of acres to determine how many square miles.
- You can divide using a calculator, or, if you’re feeling ambitious, by hand.
- For example, to convert 2,500 acres into square miles, you would calculate ${\frac {2500}{640}}=3.90625\;mi^{2}$ .

Method 2

Method 2 of 2:

Using Multiplication

1
Understand that there are 640 acres in one square mile.^{[6]
X
Research source} Both units are different ways to measure area.
- By definition a square miles is square, but an acre can be any shape.^{[7]
  X
  Research source}
2
Determine how many acres you are converting to square miles. This number will probably already be given to you, but you can also use an area calculator map to determine the acreage of a real-world tract of land.^{[8]
X
Research source}
- For example, you might want to convert 2,500 acres to square miles.
3
Multiply the number of acres by $0.0015625$ .^{[9]
X
Research source} This decimal is a way of representing the ratio of square miles to acres, or ${\frac {1}{640}}$ ${\frac {1}{640}}$ , since, for every 1 square mile you have, you have 640 acres. To put it another way, each acre is 0.0015625 of a mile.
- The decimal comes from dividing 1 by 640. So, you could also multiply by ${\frac {1}{640}}$ .
- You can multiply using a calculator, or, if you’re feeling ambitions, by hand.
- For example, to convert 2,500 acres into square miles, you would calculate $2500\times 0.0015625=3.90625\;mi^{2}$ .

Community Q&A

Question

How many hectares are in an acre?

Donagan

Top Answerer

A hectare is actually the larger measurement. One acre is the equivalent of approximately 4/10 of a hectare. A hectare is 2.47 acres.
Question

How many steps are in a mile?

Donagan

Top Answerer

Approximately 2,000, depending on the length of the steps.
Question

How many square miles in 26,000 acres?

Donagan

Top Answerer

Divide acres by 640 to find square miles. In this case, 26,000 ÷ 640 = 40.625 sq mi.