Shape of Pool	Formula for Gallons	Surface Area Formula
Rectangle or Square	depth x length x width x 7.5 = gallons	length x width / 9 = square yards of surface area
Circular	diameter x diameter x depth x 5.9 = gallons	half the diameter squared (x itself) x 3.14 / 9 = sq yds of surface area
Oval with straight sides	width x length x depth x 6.7 = gallons	3.14 x length x width / 9 = square yards of surface area