Square Miles and Acres Converter

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Using the Square Miles and Acres Converter

Use this converter to find equivalent values between two imperial units of area, the square miles (mi²) and acres (ac).

The first step is choosing between the American and British spelling of words in the text.

Move toward selecting your input unit from the two options (square miles or acres) in the ‘CONVERT FROM’ section.

The output unit can be selected in the ‘CONVERT TO’ section out of the same 2 options.

An alternative approach to selecting the input and output units is to stick with the default setting or click on the icon with 2 arrows headed in opposite directions, which swaps the order of the input and output units.

Once your input and output units are selected, type your input value into the ‘VALUE TO CONVERT’ section of the converter. Write it as a decimal number using the decimal dot if needed.

Wrap up by choosing the number of decimal places you want your result rounded toward and then click on ‘CONVERT’.

Your result will appear below the converter as a decimal number rounded to the desired number of decimal places. Alongside the result, you will also receive the conversion rate between your input and output units, alongside a convenient ‘COPY’ button, that allows you to copy and later paste your result elsewhere.

Converting Square Miles and Acres Manually

Converting units of area manually is determined by the conversion rate between the two units.

Despite the shaky history of the definition of an acre, the established definition is currently that an acre is 1/640 of a square mile.

This leads to fairly convenient conversion rates between the units, as 1 square mile is equivalent to 640 acres, while 1 acre is equivalent to 1/640 of a square mile.

This leads to two formulae that are used when converting between the units.

mi^2 = ac\div640

ac = mi^2*640

The best way to use these formulae is to choose the one that has your output unit as the subject of the formula (which is the stand-alone variable on the left side of the formula). Hence, when converting to square miles, we choose the first formula, and when we are converting to acres, we choose the second formula. The following two examples demonstrate how these formulae are used in real life for manual conversions.

EXAMPLE 1: The city of Dallas has approximately 247,000 acres in area. What is the area of Dallas in square miles?

This problem calls for converting from acres as an input unit to square miles as the output unit. This means that the first formula is the most suitable one for solving this problem. We simply substitute 247,000 for acres and solve as follows.

mi^2 = ac\div640 \\= 247,000\div640 \\= 385.9375 ~mi^2.

EXAMPLE 2: The city of Des Moines has an area of 90.7 mi². What is the area of Des Moines in acres?

This problem calls for converting from square miles to acres. This means that the second formula is the most suitable one for solving this problem, as it has acres as the subject. Substituting 90.7 for square miles will lead to the solution we are looking for.

ac = mi^2*640 = 90.7*640 \\= 58,048 ~ac.

What to do with an Acre?

An acre is a very popular unit of area that is used mostly in the USA. It often refers to the area of landmasses, especially in agriculture and farming. But a question arises of how big an acre is.

Hence, let’s have a look at the efficiency of an acre in terms of farming various crops and raising various types of animals.

Size	Usage
1 acre of wheat	Produces enough bread to last 14,600 people for a day
1 acre of peanuts	Produce enough to make peanut butter for 25,000 sandwiches
1 acre of parking space	Parking for around 150 cars
1 acre of free-roaming farmland	Grazing for 1 cow
1 acre of grazing fields	Provides enough land for 500 cage-free chickens to graze

References