Calculating the square footage needed for a swimming pool will help you understand the amount of space needed to put in an above ground or inground swimming pool. It is also a first step to calculating the volume of the pool. Pool shapes include rectangular, square, round, Lshaped or oval. Measuring the square footage will help you decide what type of pool fits in the space you have available.
Things You'll Need
 Tape measure

Measure the length of the rectangular or square pool. Measure the width. Multiply the length by the width of the pool to find the square footage. For instance, 15 feet (length) times 12 feet (width) equals 180 square feet.

Measure a round pool across to find the radius, which is half the diameter. Find the square footage by multiplying the radius times the radius times 3.14 (pi). For instance, 14 feet (radius) times 14 feet (radius) times 3.14 (pi) equals 615.44 square feet.

Calculate the square footage of a Lshaped pool by dividing the pool into two rectangular or square sections. Measure the length and width of both sections and add the square footages (using step 1).
If one section is 12by10feet and the other is 12by10feet the result will be 120 plus 120 square feet equals 240 square feet. 
Find the square footage of an oval pool by measuring the width and length at the center. Divide the two measurement by two to find the radii. Multiply the long radius by the wide radius by pi (3.14) to find the area. For instance, if the measurements are 30 feet long by 16 feet wide, the calculation would be 15 feet (length) times 8 feet (width) times 3.14 (pi) equals 376.8 square feet.