A 21' pool that is 48" high should have 10,407 gallons of water (approx). To calculate the gallons in a round swimming pool use this formula: Length x length x average depth x 5.9 = gallons of pool So in your case 21 x 21 x 4 x 5.9 = 10,407 gallons
Length x width x average depth x 5.9 gallons per cubic foot (that is the factor used in round pools) = 3,398 US Gallons.
A 2-foot round pool with 12 inches of water is holding about 23.6 gallons of water.
489.76 gallons of water.
141.06 gallons
Alittle under 10,000 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.
This pool can hold up to 1,689.7 gallons of water.
5,287.7 gallons of water.
13,594 US gallons of water.
This pool can hold a maximum of about 5,707.6 gallons of water.
1,770 gallons.
3384 gallons for every foot deep it is.