Most 8-week-old babies drink about 4 to 5 ounces of formula per feeding, roughly every 3 to 4 hours, totaling around 24 to 32 ounces in a 24-hour period. The exact amount varies from baby to baby, though, and the best approach is a combination of general guidelines and reading your infant’s own hunger and fullness cues.
Calculating Your Baby’s Daily Intake
A reliable way to estimate your 8-week-old’s needs is the weight-based formula from the American Academy of Pediatrics: about 2.5 ounces of formula per day for every pound of body weight. So a baby who weighs 10 pounds would need roughly 25 ounces total per day, while a 12-pound baby would need about 30 ounces. Spread across six to eight feedings, that works out to roughly 3.5 to 5 ounces per bottle.
This calculation gives you a useful starting point, not a rigid target. Some days your baby will be hungrier than others, especially during a growth spurt. What matters more than hitting an exact number is that your baby is gaining weight steadily and producing enough wet diapers (six or more per day).
Feeding Schedule at 8 Weeks
At this age, most formula-fed babies eat every 3 to 4 hours, which typically means six to eight bottles over 24 hours. You don’t need to wake a healthy, growing baby to feed on a strict clock. Many 8-week-olds are starting to stretch one nighttime sleep period a bit longer, going 4 to 5 hours between feeds overnight, while eating more frequently during the day to make up for it.
If your baby consistently drains every bottle and still seems hungry, it’s fine to offer an extra half-ounce or ounce. Babies at this age can’t overeat on purpose, but the feeding pace matters. Holding the bottle at a slight angle and pausing every ounce or so gives your baby time to register fullness.
Hunger and Fullness Cues to Watch For
Rather than relying on the clock alone, let your baby tell you when they’re ready to eat. Early hunger signs in the first few months include putting hands to the mouth, turning toward the bottle (called rooting), lip smacking or licking, and clenched fists. Crying is actually a late hunger cue. Feeding before your baby reaches that point makes for a calmer experience for both of you.
Fullness cues are just as important. When your baby closes their mouth, turns their head away from the bottle, or relaxes their hands, they’re signaling they’ve had enough. Resist the urge to encourage them to finish the last ounce in the bottle. Respecting these signals helps your baby develop healthy self-regulation from the start.
Stomach Size and Portion Limits
An 8-week-old’s stomach holds roughly 4 to 6 ounces at a time. That’s why smaller, more frequent feedings work better than fewer, larger ones. Offering more than your baby’s stomach can comfortably hold leads to the classic signs of overfeeding: excessive spit-up, gassiness, belly discomfort, loose stools, and more fussiness than usual. If you’re seeing these regularly, try offering slightly less per bottle and feeding a bit more often instead.
How to Tell If Your Baby Is Getting Enough
The most reliable indicator is weight gain. Your pediatrician tracks this at well-child visits, but at home you can watch for a few reassuring signs: six or more wet diapers daily, regular bowel movements, and a baby who seems satisfied (not frantic) between feedings. Most babies at this age gain about 5 to 7 ounces per week.
If your baby consistently takes less than 20 ounces a day, seems lethargic during feeds, or isn’t producing enough wet diapers, that’s worth bringing up with your pediatrician. On the other end, babies who regularly exceed 32 ounces a day generally don’t need that much, and it’s worth checking whether some of the fussiness driving those extra bottles might be gas, tiredness, or a need for comfort rather than true hunger.
Quick Reference by Weight
- 9-pound baby: ~22.5 oz/day, about 3–4 oz per bottle over 6–7 feedings
- 10-pound baby: ~25 oz/day, about 3.5–4 oz per bottle over 6–7 feedings
- 11-pound baby: ~27.5 oz/day, about 4–4.5 oz per bottle over 6–7 feedings
- 12-pound baby: ~30 oz/day, about 4–5 oz per bottle over 6–7 feedings
These are averages. Your baby’s appetite on any given day is a better guide than a chart. As long as growth stays on track and your baby seems content between feeds, you’re on the right path.