Multiplier = 7.5 for Rectangle, Square, or Free-Form poolsMultiplier = 5.9 for ring or Oval pools

Determine the average Depth:

To identify the mean depth in a pool where the bottom slopes, measure the shallow end, the deep end depth. Include them together and divide by 2 (2). 

Example:

Shallow end = 2 ft. Deep finish = 10 ft2 ft + 10 ft = 12 ft; 12/2 = 6 ft typical depth


Standard In-Ground Pool quantities in Gallons through Size
 Pool Size (in feet)3.5 ft Avg Depth4 ft Avg Depth4.5 ft Avg Depth5 ft Avg Depth
 12×247,6008,6009,70010,800
 14×2810,30011,80013,20014,700
 15×3011,80013,50015,20016,900
 16×3213,40015,40017,30019,200
 18×3617,00019,40021,90024,300
 19×3819,00021,70024,40027,100
 20×4021,00024,00027,00030,000
 22×4425,40029,00032,70036,300
 25×4529,53133,75037,96842,187
 25×5032,80037,50042,20046,900
 30×5039,37545,00050,52556,250

Above floor Swimming pool Water volumes by Size
 Size48 in Wall52 in Wall
 12 ft Round2,975 gals3,398 gals
 15 ft Round4,646 gals5,310 gals
 18 ft Round7,646 gals8,602 gals
 21 ft Round9,106 gals10,408 gals
 24 ft Round11,895 gals13,594 gals
 27 ft Round15,054 gals17,205 gals
 30 ft Round18,585 gals21,240 gals
 33 ft Round22,488 gals25,700 gals
 12×24 ft Oval5,948 gals6,797 gals
 15×30 ft Oval9,293 gals10,620 gals
 16×32 ft Oval10,573 gals12,084 gals
 18×33 ft Oval12,267 gals14,019 gals