Calculating the area of a square is the easiest of all the shapes since the sides are equal lengths. The area is the amount of space inside the square, and is expressed in square units. The perimeter, by contrast, is the distance around the outside of the square such as if you were to put a fence around it.
Measure the length of one side of the square. It doesn't matter which side you use, since the sides of a square are all the same length.
Multiply the measurement by itself to find the area. For example, if one side of the square is 5 feet, the equation is 5 time 5 equals 25.
Express the answer in square units, such as square feet (ft2), square inches, square meters, square miles or square kilometers. In the example of a square with 5-foot sides, the area is 25 square feet.
If the shape doesn't seem to have four equal sides, but does have four 90-degree angles, it may be a rectangle. In that case, find the length of one of the long sides and multiply it by the length of a shorter side to calculate the area.