How many oz do you give per feeding?

Ever since a few months old I’ve always done a calculation of 1-1.5 oz per hour. So if she’s given a bottle after 3 hours it would typically be 4.5 oz. This is the rule i followed for baby 1 and have been doing with baby 2. But now I’m seconding guessing myself based on Other babies I know . How many oz do you feed and how offend? Reference baby is currently 9 months old