A 4-week-old typically drinks 3 to 4 ounces per feeding, totaling up to about 32 ounces over a full day. That said, every baby is slightly different, and the right amount depends on your baby’s weight, whether they’re breastfed or formula-fed, and how they signal hunger and fullness throughout the day.
Ounces Per Feeding at 4 Weeks
By the end of the first month, most formula-fed babies settle into a pattern of 3 to 4 ounces (90 to 120 mL) per feeding. This is a noticeable jump from the first week of life, when a newborn’s stomach is only about the size of a marble and holds just 1 to 2 teaspoons. By day 10, stomach capacity reaches roughly 2 ounces (the size of a ping-pong ball), and it continues to grow from there.
At 4 weeks, most formula-fed babies eat every 3 to 4 hours, which works out to roughly 6 to 8 feedings in 24 hours. If your baby consistently takes 3 to 4 ounces at each of those feedings, you’ll land in the range of 24 to 32 ounces per day. The general upper limit is about 32 ounces of formula in 24 hours.
Breastfed vs. Formula-Fed Amounts
Breastfed babies tend to eat more frequently than formula-fed babies, typically nursing 8 to 12 times in 24 hours, or roughly every 2 to 4 hours. Because breast milk is digested faster than formula, shorter intervals between feedings are completely normal. You won’t be measuring ounces directly at the breast, so tracking fullness cues and diaper output is the best way to know your baby is getting enough.
If you’re pumping and bottle-feeding breast milk, the per-feeding volume is often slightly less than formula since breastfed babies tend to take smaller, more frequent meals. A range of 2 to 4 ounces per bottle is typical at this age, with more feedings spread across the day.
How to Tell Your Baby Is Hungry
Crying is actually a late sign of hunger. Well before that, your baby will give you subtler signals: putting hands to their mouth, turning their head toward the breast or bottle, puckering or smacking their lips, or clenching their fists. Catching these early cues makes feeding calmer for both of you, since a very hungry baby can gulp air and end up gassier.
When your baby is full, the signs flip. They’ll close their mouth, turn their head away from the breast or bottle, and relax their hands. These are your signals to stop, even if there’s formula left in the bottle. Letting your baby decide when they’re done helps prevent overfeeding.
Signs Your Baby Is Getting Enough
The simplest daily check is diaper output. After the first five days of life, your baby should produce at least 6 wet diapers per day. The number of dirty diapers will vary, but consistent wet diapers are a reliable sign of adequate intake. Steady weight gain at your pediatrician’s visits is the other key marker. Most babies regain their birth weight by about 2 weeks and then gain roughly 5 to 7 ounces per week through the first few months.
The 3-to-6-Week Growth Spurt
Right around this age, many babies hit a growth spurt. Common windows are 2 to 3 weeks and again at 6 weeks, so a 4-week-old can easily be in the middle of one. During a growth spurt, your baby may want to eat more often, seem fussier than usual, and nurse or take bottles as frequently as every 30 minutes for a day or two.
If you’re breastfeeding, this can feel like you’re nursing around the clock. That’s actually your baby’s way of signaling your body to produce more milk. The increased demand is temporary and typically resolves within a few days as your supply adjusts. For formula-fed babies, you might notice they drain bottles faster or seem hungry sooner than their usual 3-to-4-hour window. Offering an extra ounce or an additional feeding during these stretches is fine as long as you’re still following their hunger and fullness cues.
Signs of Overfeeding
Overfeeding is more common with bottle-fed babies because milk flows from a bottle with less effort than from the breast, making it easy to take in more than the stomach can comfortably handle. Signs include frequent spit-up (more than the occasional dribble), gas and belly discomfort, loose stools, and unusual fussiness after feedings.
A few practical ways to avoid this: use a slow-flow nipple, pause partway through the bottle to burp your baby, and resist the urge to encourage them to finish the last half-ounce if they’re showing signs of fullness. Paced bottle feeding, where you hold the bottle more horizontally and let your baby control the flow, can also help them self-regulate how much they take in.
When Intake Falls Outside the Typical Range
Some babies consistently eat a little less or a little more than the 3-to-4-ounce guideline, and that can be perfectly normal. What matters more than hitting an exact number is the overall pattern: steady weight gain, at least 6 wet diapers a day, and a baby who seems satisfied after feedings. If your baby regularly takes well under 2 ounces per feeding, refuses to eat, or seems lethargic, those are worth a call to your pediatrician. On the other end, consistently pushing past 32 ounces of formula per day or spitting up large amounts after most feedings may signal that portions need adjusting.