A 9-month-old typically drinks between 24 and 32 ounces of breast milk or formula per day, spread across 4 to 6 feedings. The exact amount varies from baby to baby, especially as solid foods start making up a larger share of their diet.
Formula and Breast Milk Amounts
For formula-fed babies at this age, each bottle is usually 6 to 7 ounces, offered every 3 to 4 hours during the day. That works out to about 4 to 6 bottles in a 24-hour period, with most babies no longer needing overnight feeds. Totals for the day generally land somewhere around 24 to 32 ounces.
Breastfed babies follow a similar rhythm of about 4 to 6 nursing sessions per day, though it’s harder to measure exact ounces. A single nursing session typically delivers 3 to 5 ounces, but the best gauge of whether your baby is getting enough isn’t volume. It’s output: if your baby produces at least 3 wet diapers a day and is gaining weight steadily, they’re likely well-fed. Fewer than 3 wet diapers in a day can be a sign of dehydration.
How Solid Foods Change the Math
At 9 months, your baby is probably eating 3 small meals of solid food plus a couple of snacks throughout the day. The CDC recommends offering something to eat or drink every 2 to 3 hours, which adds up to about 5 or 6 eating and drinking opportunities daily. As solids increase, milk intake naturally decreases a bit. That’s normal. Breast milk or formula still provides the majority of your baby’s calories and nutrition at this age, but you don’t need to force a full bottle if your baby seems satisfied after a smaller one.
A practical approach: offer breast milk or formula before solid meals, not after. This ensures your baby gets enough milk before filling up on foods that are less calorie-dense. By around 12 months, the balance will shift and solids will become the primary source of nutrition.
How Much Water Is Safe
Babies between 6 and 12 months old can have small amounts of plain water: 4 to 8 ounces per day. This is in addition to their breast milk or formula, not a replacement. An open cup or straw cup at mealtimes is a good way to introduce water and build the skill of drinking from a cup. Too much water can fill up a small stomach and crowd out the milk and food your baby actually needs for growth.
What Not to Offer Yet
Cow’s milk should wait until your baby turns 1. Before that age, cow’s milk doesn’t supply enough vitamin E, iron, or essential fatty acids. The protein and fat in cow’s milk are also harder for a baby’s digestive system to break down. Stick with breast milk, formula, or both until the first birthday, then transition to whole cow’s milk.
Juice, flavored milks, and sweetened drinks aren’t necessary at any point during infancy. They add sugar without meaningful nutrition and can set up a preference for sweet drinks later on.
Knowing When Your Baby Has Had Enough
Nine-month-olds are surprisingly good at communicating when they’re full. Watch for these cues: pushing the bottle or food away, closing their mouth when you offer more, turning their head to the side, or using hand gestures and sounds to signal they’re done. Forcing a baby to finish a bottle after they’ve shown these signs can override their natural ability to regulate hunger, which isn’t helpful in the long run.
On the flip side, some babies go through growth spurts where they want more than usual for a few days. That’s also normal. Let your baby’s hunger and fullness cues guide portion sizes rather than aiming for an exact number every single day. The daily range of 24 to 32 ounces of milk is a useful guideline, not a rigid target.