For circular pools, have a friend help hold one side of the tape measure on the other side of the pool. This way you can walk in unison from one end of the pool to the other to find the diameter. The largest distance you can measure is the diameter.
An above-ground pool is an excellent option for those who would like the availability of a pool at home without the high price tag of a more permanent in-ground pool. Above-ground pools are widely available in three different shapes: circular, oval and rectangular. Measuring an existing above-ground pool is a simple task that can be easily accomplished with a tape measure and a friend if you want to save time. Carefully measure the length, width and height of your pool easily and without error.
Measure the height of your above-ground pool's walls. Take the tape measure and place the end firmly at the bottom of the wall. Draw the tape measure to the top of the wall and record the measurement. Typically, above-ground pools come in two heights: 48 and 52 inches.
Measure the length and width of a rectangular or oval above-ground pool. Measure the width by placing the end of the tape measure on the top and in the middle of one of the pool's long walls and drawing it across the top to the end of the opposite wall. Do the same for the length, but measure in the middle of one of the pool's short walls.
Measure a circular pool. Measure the distance across the top of the pool from one wall to another. Make sure that you are measuring the diameter of the circular pool. The tape measure should cross the direct center of the pool.