Do all flex fit hat's fit the same?

I'm in consideration of buying a new hat and the one I want to buy is a flex fit, it is online so I cannot try it on. I have a flexible type hat (not the flex fit company and I don't know what the brand of the hat I want to buy is) and it fits fine I also have a fitted hat, 7 5/8 (I know kinda big). So if I buy this new flex fit hat will it fit just as my other hat does or can it be bigger or smaller?