The calculation is:
Diameter x Diameter x Depth X 5.9 = Number of Gallons
For a 15-foot round pool with a water depth of 3 ft: 15x15x3x5.9 = 3,982 gallons.
Since you did not specify the depth of the water, I will provide an answer for a couple of likely depths below.
Please note that this is the ACTUAL water depth NOT the height of the pool wall (the water is usually around 6 inchs lower than the wall height).
36 in depth: 3,982 gallons 42 inch depth: 4,646 gallons 48 inch depth: 5,310 gallons
About 4,640 gallons.
Does "15 foot round" refer to Perimeter, Diameter or Radius.
A 33-foot round pool with 4 feet of water contains about 25,700 gallons of water.
About 28,913 gallons of water.
A 36-foot round pool with 52 inches of water is holding around 33,109 gallons. If the water depth was 48 inches, the gallons decreases to 30,585 gallons.
A 2-foot round pool with 12 inches of water is holding about 23.6 gallons of water.
489.76 gallons of water.
About 755 gallons of water.
This 8-foot round pool, when filled with 27 inches of water, is holding about 850 gallons of water.
Two feet of water in an 8-foot round pool is about 755 gallons.
A 24-foot round pool with 50 inches of water in it is holding about 14,158 gallons.
A round pool that is 16 feet across and is filled with 48 inches of water will contain about 6,041 gallons of water.
4,047.4 US gallons of water.
13,594 US gallons of water.
5,287.7 gallons of water.
About 20,030 gallons of water.
2,549 US gallons of water.
11,709 US gallons of water.
A 4' x 4' round tank holds 375.5 gallons.
This pool, when filled with 4.5 feet of water, will contain about 15,300 gallons of water.