A formula-fed 9-month-old typically drinks 24 to 32 ounces of formula per day, spread across several feedings. Breastfed babies continue nursing on demand. At this age, though, solid foods are playing a bigger role in your baby’s diet, so the total amount of milk naturally starts to taper down from what it was a few months ago.
Daily Milk Amounts by Feeding Type
For formula-fed babies, 24 to 32 ounces per day is the general range recommended by the American Academy of Pediatrics. That usually works out to about four or five bottles of 6 to 8 ounces each. Your baby’s appetite will vary from day to day, so follow their hunger and fullness cues rather than fixating on hitting an exact number. If they turn away from the bottle or lose interest, the feeding is done.
For breastfed babies, there’s no precise ounce count to aim for because breast milk intake is harder to measure. The AAP recommends nursing on demand, which at 9 months often means four to five sessions a day, sometimes more. Some babies nurse frequently but for shorter stretches, while others take fewer, longer feeds. Both patterns are normal. If you’re pumping and bottle-feeding breast milk, somewhere around 24 to 30 ounces per day is a reasonable ballpark, but again, your baby’s cues are the best guide.
How Solid Foods Change the Equation
At 9 months, your baby is likely eating two to three meals of solid food plus a couple of snacks each day. The CDC recommends offering something to eat or drink every 2 to 3 hours, which adds up to about five or six eating opportunities across the day. As your baby eats more solids, they’ll naturally drink a bit less milk. This is expected and healthy. Breast milk or formula is still the primary source of nutrition at 9 months, but that balance gradually shifts over the next few months until solids take the lead closer to the first birthday.
A practical approach: offer milk first thing in the morning and before naps or bedtime, and serve solid meals in between. Some parents prefer to give a small milk feeding before solids so the baby isn’t too hungry to practice eating, while others offer milk after solids. Either order works. What matters is that your baby gets both throughout the day.
Why Cow’s Milk Should Wait
Whole cow’s milk shouldn’t replace breast milk or formula until your baby turns 12 months old. Before that age, cow’s milk contains too many proteins and minerals for a baby’s kidneys to handle efficiently. It also lacks the right balance of nutrients your baby needs, particularly iron. Perhaps most concerning, cow’s milk can cause small amounts of intestinal bleeding in young infants, which increases the risk of iron deficiency over time.
Small amounts of dairy in food form, like plain yogurt or cheese, are generally fine at 9 months. The restriction is specifically about using cow’s milk as a drink in place of formula or breast milk.
Introducing a Cup
Nine months is a great time to start practicing with a cup if you haven’t already. The AAP suggests offering a cup as early as 6 months, when solid foods are introduced. You can try a sippy cup with a spouted lid, a straw cup, or even an open cup with a small amount of liquid. Some babies skip the sippy cup entirely and go straight to a regular cup or straw. Put breast milk or formula in the cup at first so the taste is familiar.
At this stage, the cup is for practice, not for replacing bottles or nursing sessions. Your baby will spill, dribble, and play with it. That’s all part of learning. Weighted cups that tip back upright can help reduce mess, but they’re optional.
Water at 9 Months
Babies between 6 and 12 months old can have 4 to 8 ounces of plain water per day. Offer it in a cup with meals or snacks. Water at this age is about getting your baby comfortable with the taste and the cup, not about replacing any milk. Too much water can fill up a small stomach and crowd out the calories and nutrients from milk and food.
Vitamin D Needs
Babies under 12 months need 400 IU of vitamin D daily. If your baby is exclusively breastfed or gets a mix of breast milk and formula, they need a vitamin D supplement every day starting from shortly after birth. Formula-fed babies who drink 32 ounces or more of formula daily get enough vitamin D from the formula itself and don’t need a separate supplement. At 9 months, many babies are drinking less than 32 ounces because of solids, so even formula-fed babies may benefit from a supplement at this point.
Signs Your Baby Is Getting Enough
The clearest sign that your baby is drinking enough milk is steady weight gain over time. Your pediatrician tracks this on a growth chart at each well visit, and what matters is a consistent pattern, not any single measurement. Between visits, there are a few things you can watch for at home:
- Wet diapers: At least six heavy, wet diapers in a 24-hour period indicates good hydration.
- Contentment after feeding: Your baby seems satisfied and relaxed after most feedings rather than fussy or still rooting.
- Moist mouth: Their lips and mouth look moist after feeds, not dry or sticky.
- Rounded cheeks during sucking: If cheeks stay full rather than hollowing inward, your baby is getting a good latch and milk flow.
A day or two of lower intake is rarely a concern, especially during teething, mild illness, or a developmental leap. What you’re looking for is the overall trend across weeks, not a perfect daily number. If your baby consistently refuses milk, has fewer than four wet diapers a day, or seems lethargic, that’s worth a call to your pediatrician.