The perimeter is the distance around the outside of the square, and not the area, which is the space inside of the square. Knowing the perimeter is useful in a number of disciplines, including construction. Fortunately, finding the perimeter of a square is a straightforward operation that can be achieved in a few short steps.
Make sure the shape is a square. All four sides on a square are exactly the same size, and all four angles are right angles, or 90 degrees.
Find the length of any one side of the square; it doesn't matter which side, because they are all the same size. You can use a ruler to do this, but make sure to keep track of the units you used, such as inches or centimeters.
Take the measurement of the side and multiply it by 4. You can use a calculator to do this. Alternatively, take the side length and add it to itself 3 times. Either operation will yield the perimeter. For example, if you've measured the side of the square to be 18 inches:
18 * 4 = 72; or
18 + 18 + 18 + 18 = 36 + 36 = 72
The perimeter is therefore 72 inches.