How much formula does a baby need?
The American Academy of Pediatrics (AAP) gives a simple rule: on average, a baby takes about 2½ ounces (75 mL) of formula a day for every pound (453 g) of body weight, and usually no more than about 32 ounces (960 mL) in 24 hours. A 10-pound baby needs about 25 ounces a day; spread over 7 feeds, that's about 3½ ounces per bottle.
The rule doesn't apply in the first week, when a baby's stomach is tiny: the AAP says no more than about 1 to 2 ounces (30 to 60 mL) per feed. And it's an average, not a target. The AAP notes that babies regulate their own intake from day to day, so let your baby tell you when they've had enough.
Formula amounts by age
| Age | Per feed | How often | Source |
|---|---|---|---|
| First week | No more than 1–2 oz (30–60 mL) | About every 2–3 hours; 8–12 times a day | AAP, CDC |
| End of first month | At least 3–4 oz (90–120 mL) | About every 3–4 hours | AAP |
| About 2 months | 4–5 oz (120–150 mL) | Every 3–4 hours | KidsHealth |
| 4 months | 4–6 oz (120–180 mL) | Depends on how often they eat | KidsHealth |
| 6 months | 6–8 oz (180–240 mL) | 4 or 5 feedings a day | AAP |
| 6–12 months | Alongside solid foods | About 5–6 times a day | CDC |
The calculator suggests a number of feeds for your baby's age from these ranges. Change it to match your baby: the amount per bottle is the daily total divided by the feeds.
How much pumped breast milk to put in a bottle
Breast milk works differently. Research summarized by KellyMom finds that exclusively breastfed babies take an average of about 25 ounces (750 mL) a day between 1 and 6 months, with most between 19 and 30 ounces (570 to 900 mL). A study that followed breastfed babies from 1 to 6 months found their total 24-hour milk intake stayed constant even as they grew (Kent et al., 2013).
So for pumped milk, divide 25 ounces by the number of feeds in a day. A baby who feeds 8 times needs about 3 ounces per bottle. KellyMom calls this a ballpark figure: babies won't drink the same amount at every feed, so watch your baby's cues rather than encouraging them to finish the bottle. Start there and adjust.
Signs your baby is hungry or full
Watch your baby, not the bottle. The AAP says a baby who becomes fidgety or easily distracted during a feed is probably finished, while one who drains the bottle and keeps smacking their lips may still be hungry. KidsHealth adds that a full baby may suck with less enthusiasm, stop, or turn away from the bottle.
Babies also have days when they seem hungrier than usual, often during growth spurts. KidsHealth lists common ones at around 7 to 14 days, 3 to 6 weeks, 4 months and 6 months. Feed on demand during these times.
When to talk to your pediatrician
If your baby consistently seems to want much more or much less than these amounts, the AAP recommends discussing it with your pediatrician. At checkups, your baby's growth on the growth chart is the best sign they're getting enough; you can check where they are with our baby growth percentile calculator. Always mix formula exactly as the package says.