How many gallons of water does a 28 foot round 4ft deep above ground pool hold?

It depends on how deep you fill the pool. So, let's take the most common depths for a 33-foot round pool; 3, 4 and 5 feet:

1. For 3 feet of water the total gallons will be about 19,275.
2. For 4 feet of water the total gallons will be about 25,700.
3. For 5 feet of water the total gallons will be about 32,125.