Square Miles and Square Kilometers Converter

With this converter, you can convert between the largest commonly used unit of area within the metric system (the square kilometer) and the largest commonly used unit of area within the imperial system (the square mile).

Start by choosing the spelling of the word meter, which affects how the word kilometer is spelled, between the American spelling (meter) and the British spelling (metre).

After that, move toward selecting the input unit in the ‘CONVERT FROM’ section, where you can choose between square miles ($mi^2$) and square kilometers ($km^2$).

Choosing the output unit takes place in the ‘CONVERT TO’ section, where the choice comes down to the same two options as before. 

You can also stick to the preselected units or swap them around by clicking on the icon with two arrows headed in opposite direction.

Once you are happy with the unit selection and spelling, move toward the ‘VALUE TO CONVERT’ section, where you type in the input value as a decimal number using the decimal dot.

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

Your result will appear below the converter as a decimal number rounded to the desired number of decimal places. You will also receive the conversion rate between the input and output units you selected.

Feel free to take advantage of the convenient ‘COPY’ icon next to your result, which allows for easy copying and pasting of your result elsewhere.

Converting Square Miles and Square Kilometers Manually

Both of the units of area we are discussing here are defined by units of length.

A square mile is equivalent to the area of a square with a side length of a mile, while a square kilometer is equivalent to the area of a square with a side length of a kilometer. 

We know that a mile is equivalent to approximately 1.61 km. 

Hence, squaring 1 mile and 1.61 km leads to a conversion rate of the units of area as 1 $mi^2$ is equivalent to 1.612 $km^2$ which is equal to 2.5921 $km^2$.

This means that the conversion rate of square miles to square kilometers is 1:2.5921.

We can derive two formulae from this conversion rate.

The choice of the right formula depends on the input and output units. For the simplest possible calculations, always choose the formula with the subject being the output unit of your calculation. In the case of the first formula, square kilometers are the subject, while in the case of the second formula, square miles are the subject.

EXAMPLE 1: What is the area in $km^2$ of a field with an area of 7 $mi^2$? Round your result to 2 decimal places.

As our output is in $km^2$, we will be choosing the first formula and substituting 7 for $mi^2$. We get the following calculations.

We round this result to 2 decimal places and get 18.14 $km^2$.

EXAMPLE 2: What is the area in square miles of a town that has an area of 4.3 $km^2$? Round your result to 2 decimal places.

Since the output is in square miles, we choose the second formula to solve this problem. We substitute 4.3 for $km^2$ and get the following calculations.

We round the result to 2 decimal places and get 1.66 $mi^2$.

World’s Largest Cities

Square kilometers and miles are often used to describe areas of towns, cities, and countries. In order to get a better idea of the size comparison between square miles and square kilometers, we offer a table of the 10 largest cities (by population) in the world and their areas expressed in both units.

References:

https://purneauniversity.org/largest-city-in-the-world/