There are about 7.481 gallons per cubic foot. So if your 12 foot by 8 foot pool is filled 4 feet deep you will need 12 x 8 x 4 x 7.481 = 2,873 gallons of water.
17,953.2 gallons
615,142 gallons of water are needed to fill this cylinder.
It will take 5,104.1 gallons of water to fill this cylinder.
If this is a round pool 18 feet across and you fill it with 4 feet of water, it contains 7,646 gallons of water.
It would require 2,937.6 US gallons of water to fill the pipe.
An 18-foot round pool with 3 feet of water contains 5,734.8 gallons of water. If you fill it to 4 feet deep it increases to 7,646 gallons of water.
A pool this size with an average depth of 16 feet requires 462,560 gallons of water to fill it to the top.
If you fill it with 4 feet of water (48 inches), the pool will contain about 5,310 gallons of water.
1795 gallons, if you fill it to the brim.
Three feet of water in a 12-foot round pool is about 2,550 gallons.
4,625.6 gallons.
(3.5 feet) * PI * ((9 feet)^2) = 6 662.46122 US gallons