A 5-week-old typically drinks 3 to 5 ounces of formula per feeding, about 6 to 8 times in a 24-hour period. That works out to roughly 20 to 28 ounces total per day, though the exact amount depends on your baby’s weight and appetite. The simplest way to calculate it: multiply your baby’s weight in pounds by 2.5 ounces.
Calculating Your Baby’s Daily Total
The standard guideline is 2.5 ounces of formula per day for every pound of body weight. A 5-week-old who weighs 9 pounds, for example, needs about 22.5 ounces over 24 hours. A 10-pound baby needs about 25 ounces. Spread that across 6 to 8 feedings and you get roughly 3 to 4 ounces per bottle.
Some babies at this age will take closer to 5 ounces per feeding, especially if they’re going slightly longer stretches between bottles. That’s fine as long as the daily total stays in a reasonable range and your baby seems comfortable after eating. There’s no single magic number. The weight-based formula gives you a ballpark, and your baby’s hunger cues fill in the rest.
What a Feeding Schedule Looks Like
At 5 weeks, most formula-fed babies eat every 3 to 4 hours during the day. Overnight, some babies start stretching to 4- or even 5-hour gaps between feedings, though many still wake every 3 hours. You’ll likely be doing somewhere between 6 and 8 bottles in a full day.
Rigid schedules don’t work well at this age. Feeding on demand, guided by your baby’s hunger signals, is more reliable than watching the clock. If your baby drained the last bottle two hours ago and is showing hunger cues again, it’s fine to offer another one. Babies don’t eat the same amount at every feeding. A smaller bottle at one feed followed by a larger one at the next is completely normal.
Reading Hunger and Fullness Cues
Your baby can’t tell you they’re hungry in words, but the signals are consistent. Bringing hands to the mouth, turning toward the bottle (called rooting), lip smacking, and clenched fists all mean it’s time to eat. Crying is actually a late hunger signal. If you can catch the earlier cues, feedings tend to go more smoothly.
Fullness cues are equally important. When your baby closes their mouth, turns away from the bottle, or relaxes their hands, they’re done. Resist the urge to encourage them to finish the last half-ounce. Babies are better at self-regulating intake than we give them credit for, and pushing past fullness cues can lead to discomfort.
Growth Spurts Around This Age
Five weeks sits right between two common growth spurts, one around 2 to 3 weeks and another near 6 weeks. If your baby suddenly seems hungrier than usual, wants to eat more frequently, or acts fussy between feedings, a growth spurt is the likely explanation. During these periods, your baby may want an extra ounce per bottle or an additional feeding or two per day.
Growth spurts typically last a few days to a week. Follow your baby’s lead, offer more when they seem hungry, and expect things to settle back to a more predictable pattern afterward. Babies gain about an ounce per day in these early months, and the increased appetite during spurts is part of what fuels that rapid growth.
Signs You’re Feeding the Right Amount
The best confirmation that your baby is getting enough formula comes from diapers and weight gain. After the first week of life, you should see at least 6 wet diapers per day. Steady weight gain, tracked at your pediatrician visits, is the other key measure. Most babies at this age gain about an ounce a day, or roughly 5 to 7 ounces per week.
If your baby seems satisfied after feedings, is alert during wake periods, and is hitting those diaper and weight benchmarks, the amount of formula you’re offering is working.
Signs of Overfeeding
Overfeeding is more common with bottle feeding than breast feeding because milk flows from a bottle with less effort, making it easier for babies to take in more than they need. The signs are usually straightforward: frequent spitting up (more than the normal small amounts), gassiness, belly discomfort, and loose stools. A baby who seems uncomfortable or fussy right after finishing a bottle may have taken in too much.
A few strategies can help. Use a slow-flow nipple, which makes your baby work a bit harder and gives their brain time to register fullness. Pause once or twice during the feeding to burp and give your baby a chance to signal whether they want more. And pay attention to those fullness cues rather than fixating on emptying the bottle. If your baby regularly leaves half an ounce, start preparing slightly smaller bottles to reduce waste.
When Intake Looks Too Low
If your 5-week-old consistently takes less than 2 ounces per feeding, seems uninterested in eating, or produces fewer than 6 wet diapers a day, that’s worth a conversation with your pediatrician. The same goes for weight gain that stalls or drops off. Some babies are naturally smaller eaters and grow just fine, but a noticeable decline in appetite or output is a signal to check in.
Keep in mind that individual feedings vary. One 2-ounce bottle doesn’t mean anything is wrong if the next one is 4 ounces. It’s the pattern over a full day, and over several days, that matters.