How do you know when a basketball is fully pumped?

I was pumping my basketball and wanted to know, are there any tips on how to know when your basketball is ideally pumped? I remember my gym teacher telling me that if u let it go from you full height, it should bounce up to the waist or something like that; i'm not entirely sure.How do you know when a basketball is fully pumped?
Let it go from your head (Like you said) and while on it's way down bend your arm and have your elbow ''='' to the ground and if it bounces up to your elbow, it's pumped good.How do you know when a basketball is fully pumped?
The elbow test is what officials do to test a game ball. The rule book says that when it drops from 6 feet, it should bounce to 4 feet.

carolina skiff