I assume your measurements are in feet. Also I assume you are giving SANTAI4D length x depth x hight. If so the calculation is 48″x 24″x 12″ divided by 231 which is appr Read more Swimming Pools +2 How many gallons of water to fill a pool that’s 12′ round and 30 high? Asked by Wiki User Look, this is simple geometry…look it up…stop playing…