Milk Amount

Other babies around my son’s age are drinking about 4-6 ounces every 4 hours. I’m nursing as much as I can, and topping up with some formula. My son has about 50ml of formula which would mean to be around the same amount as the other babies he’d need almost 3 ounces? I doubt he’s getting that much from my milk.

My question is, does a breastfed baby actually drink more amount-wise? Or would the amounts be similar? Like 4 ounces formula=4 ounces breastmilk?