If you’re breastfeeding, you probably haven’t thought much about how many ounces your baby is getting. He nurses until he’s full, and then you feed him again when he shows signs of hunger. But if you need to use bottles because your baby needs supplements, for occasional outings, or when returning to work, you may need to focus a little on amounts.
The Academy of Breastfeeding Medicine recommends that healthy term breastfed babies need very little per feeding in the early days – ½ ounce or less per feeding in the first 24 hours, and slowly increasing to 1-2 ounces per feeding by day 4. The amount will slowly increase.
Research shows that a breastfed baby takes anywhere from 19 to 30 ounces per day after the first month, with the average being 25 ounces per day. To determine how much milk you will need for your breastfed baby, take the number of times he is eating each day and divide 25 by that number. For example, if your baby is feeding 10 times each day, 25 divided by 10 would be 2.5 ounces. So, your baby would need 2.5 ounces if you were to replace a breastfeeding session with a bottle-feeding one. If he’s eating less often, the amount in each bottle will need to increase.
When you choose to formula feed from birth, your baby’s healthcare provider will likely provide you with information about how much your baby should be eating. It’s normally recommended that you provide your baby with a bottle of formula every 2-3 hours during the newborn period, and as he or she grows, lengthen that to every 3-4 hours. According to the American Academy of Pediatrics, “On average, your baby should take in about 2 1⁄2 ounces of formula a day for every pound of body weight.” Research shows that formula fed babies typically consume larger volumes than breastfed babies. In general, your formula fed baby will probably need:
Newborn (birth to 1 month): 1.5 to 3 ounces per feeding
Age 2 months: 4 to 5 ounces per feeding
Age 4 months: 4 to 6 ounces per feeding
Age 6 months: 6 to 8 ounces per feeding
No matter whether you’re providing formula or breastmilk by bottle, you can feed your baby responsively by holding him close, making eye contact, talking to him when feeding, and switching sides partway through the feeding. Tickle your baby’s lips with the bottle, and allow him to latch to the teat as he would at the breast. Give him frequent breaks, and hold that bottle almost horizontally so that the flow is slowed. You may even want to consider using a slow flow nipple. When your baby pushes the nipple out of his mouth or turns away, he is likely done, whether the bottle is empty or not. This type of paced bottle-feeding is an excellent tool if you are going back and forth between the breast and the bottle.
When drinking from the breast, a baby needs to work to get the milk. Any time he stops working, the milk stops flowing. Not so with the bottle. Each time he swallows when bottle feeding, his mouth fills again with fluid, so he needs to swallow again filling his mouth once more with milk, and on and on until all of the milk from the bottle is gone. So it’s not unusual for your baby to keep drinking from the bottle until it’s empty. It doesn’t necessarily mean he was starving – it means that he had no choice but to keep swallowing. Paced bottle-feeding can also help you to avoid feeding your baby too much. Overfeeding is a concern with bottle-feeding, not matter whether you’re using formula or expressed breastmilk.
When a baby gains too quickly with bottle-feeding, the risk of obesity later in life is increased. And overfed babies are uncomfortable! Overfeeding is often misdiagnosed as colic, reflux or even allergy. If your baby spits up more than usual, has too many very wet diapers each day, is gaining far above the norm, is irritable and has trouble sleeping, you may be overfeeding.
Babies are hard-wired to tell us when they’re hungry, and if we listen, they will let us know when they’re full. The problem happens when we expect babies to join the ‘clean plate club,’ making sure they finish every last drop in the bottle whether they’re still hungry or not.
In addition, some babies are overfed because their desire to suck is always interpreted as a sign of hunger. It’s normal for babies to fall asleep while sucking – it’s comforting to them. But for a bottle fed baby, the continued need to suck comes with a continuous flow of fluid. This sets the baby up for taking in more than he really needs to feel full.
You will learn your baby’s individual cues, and will get to know when your baby wants to eat and when your baby just wants comforting. This will help you to better determine your baby’s own schedule for feedings. If your baby is occasionally cared for by others it may be important that they learn your baby’s schedule, too. Keep in mind the average amount per day (around 25 ounces) and the number of times per day your baby typically eats, and you can come up with a feeding plan to allow your baby to get just enough to eat without the problems of overfeeding.
 Kellams, A., Harrel, C., Omage, S., Gregory, C., Rosen-Carole, C., & Academy of Breastfeeding Medicine. (2017). ABM Clinical Protocol# 3: Supplementary Feedings in the Healthy Term Breastfed Neonate, Revised 2017. Breastfeeding Medicine, 12(4), 188-198.