I think tt's really hard to gauge as different babies feed differently and it also depends on ur letdown. Some moms have fast letdown leading to faster flow so their babies will drink more within the same amt of time. Maybe u can try pumping and see what's ur output for 5 min, tt can give u an estimate. My 3 mth old baby boy is breastfed and given bottle too. Typically within the first 5 min, he'll finish abt 120ml in bottle, total of 180ml within 10 min but when I breastfeed him, he'll take ard 15-30min. My lactation consultant says there's no fixed amt as it really depends on the mom and baby. For me, I have constant clogged ducts so baby takes longer to feed so she told me to just monitor his wet diapers, weight gain and how satisfied is he aft feed and not to be too concerned abt the amount.