Calculating the Area of a Square from Its Perimeter

A square is a figure with four equal length sides, and the perimeter of a square is the total distance around the outside of the shape. Calculate the perimeter by adding all four sides together. The area of a square is the amount of surface the shape covers and is measured in square units. You can calculate the area of a square by using both the length of one side and its perimeter.

Step 1

Divide the perimeter length by 4 to get the measurement for each side of the square. For example, a square with a perimeter of 20 inches has four sides of five inches each.

Step 2

Multiply the length of one side by another side. With a square, because all sides are equal, you are essentially squaring the side. Multiplying 5 times 5 equals 25 in our example.

Step 3

Convert the measurement to square units. Keep the units static across the board. If you use inches for the perimeter, the area is in square inches.