###### Asked in Swimming Pools

Swimming Pools

# How much water will an 18 foot pool by 4 feet deep hold?

## Answer

###### Wiki User

###### July 14, 2009 6:21PM

Have a calculator handy? pi x r squared x depth x 7.5 = capacity in gallons. 18' pool has a 9' radius Radius squared is 9x9 or 81. Multiply 81 by pi (3.14)= 254.34. This is the square footage of the pools surface. Also good to know if you want to add a heater or some chemicals that require surface area numbers. The surface area times the depth gets you the cubic feet capacity of the pool, again sometimes good to know. So, 254 x 4' deep = 1,016 cubic feet. There are 7.5 gallons of water in a cubic foot. 1,016 x 7.5 = 7,620 gallons