Baby formula amount calculator

How much formula does a baby need in a day?

The American Academy of Pediatrics (AAP) gives a rule of thumb: on average, about 2½ ounces (75 mL) of infant formula a day for every pound (453 g) of body weight, and usually no more than an average of about 32 ounces (960 mL) in 24 hours. For a 10 lb (4.5 kg) baby that is 25.0 ounces (739 mL). An 8 lb baby comes to 20.0 ounces, and any baby heavier than 12.8 lb (5.8 kg) reaches the 32-ounce ceiling: a 14 lb baby would be 35.0 ounces by the rule, but the guidance caps it at 32.

How much formula should a baby take at each feeding?

Divide the day’s total by the number of feedings. With 25.0 ounces a day and 6 feedings, that is 4.2 ounces (123 mL) per feeding. The AAP says that in the first week a baby should take no more than about 1 to 2 ounces (30 to 60 mL) per feeding, and the CDC suggests offering 1 to 2 ounces every 2 to 3 hours in the first days, then giving more if the baby shows signs of hunger. By the end of the first month the AAP expects at least 3 to 4 ounces (about 120 mL) per feeding about every 3 to 4 hours, and by 6 months 6 to 8 ounces (180 to 240 mL) at each of 4 or 5 feedings in 24 hours.

How often should a formula-fed baby eat?

The CDC says most formula-fed newborns eat 8 to 12 times in 24 hours at first, and that feedings spread out to about every 3 to 4 hours in the first weeks and months. A newborn who sleeps longer than 4 to 5 hours in the first weeks and misses feedings should be woken for a bottle, the AAP says. Around 2 to 4 months, or once a baby weighs more than about 12 lb (5.4 kg), most babies no longer need a middle-of-the-night feeding, and daytime gaps may stretch to 4 or 5 hours. From 6 to 12 months, the CDC counts formula or solid foods about 5 to 6 times a day, with formula falling as solids rise.

Is the weight rule the same for every baby?

No. It is an average. The AAP gives the figure as an average and notes that babies often regulate their own intake. The CDC adds that babies generally take what they need at each feeding and stop when they are full. If your baby consistently wants more or less than the averages, the AAP’s advice is to talk with your pediatrician; the amounts here are not a prescription.

What if my baby is breastfed too?

This calculator is for a baby who takes only formula. A breastfed baby, or a baby who gets both, takes in milk differently, and this page cannot turn ounces of formula into minutes at the breast. If you combine breast milk and formula, ask your pediatrician or a lactation consultant how to plan feedings; this page cannot split the total between the two.

Does the baby need vitamin D with formula?

The CDC says babies who get about 32 ounces (about 1 liter) or more of formula a day do not need extra vitamin D, and babies who take less than that do need it. Ask your pediatrician about a supplement if your baby is on the low side.

Which is more important, the number or the baby?

The baby. The numbers are averages from public-health guidance; your own baby’s growth, followed by your pediatrician, is what matters. Concerns about feeding, spitting up, fast or slow weight gain or refusing feeds are reasons to call your pediatrician, not to adjust the amounts yourself.

Worked example

A baby weighs 10 lb (4.5 kg). The rule gives 10 × 2.5 = 25.0 ounces (739 mL) over 24 hours. At 6 feedings that is 4.2 ounces each; at 8 feedings, 3.1 ounces; at 5 feedings, 5.0 ounces. The table under the result lists the choices. A baby weighing 14 lb (6.4 kg) would be at 35.0 ounces by the rule, but the AAP’s ceiling of about 32 ounces applies, which is why the calculator shows 32.

Limits of this guide

This page is built for healthy, full-term babies who take standard formula; premature babies, babies with medical conditions and babies on special formulas need individual advice from their doctor. It also does not apply in the first days, when a newborn’s stomach is small and the AAP’s limit of about 1 to 2 ounces per feeding governs. The AAP’s figures are not fully consistent with each other at the top end: 8 ounces at each of 5 feedings, the upper end of the 6-month guide, would be 40 ounces, more than the 32-ounce daily limit from the same page, which is one more reason to follow your baby and your pediatrician rather than a single number. Formula must be prepared exactly as the label says.

Common mistakes

Treating 32 ounces as a goal rather than a ceiling, urging a baby to finish a bottle when the baby has shown signs of being full, using the weight rule for the first week, and adding the formula portion to a breast-milk estimate are the usual errors. A baby’s weight changes quickly: a rule that fit last month may not fit now, so re-enter the current weight, ideally from the last weigh-in at the pediatrician.

Sources: American Academy of Pediatrics, HealthyChildren.org, “Amount and Schedule of Formula Feedings” (healthychildren.org, read October 28, 2026: 2½ oz per pound, about 32 oz a day, 1 to 2 oz per feeding in the first week, 3 to 4 oz per feeding by the end of the first month, 6 to 8 oz at 4 or 5 feedings by 6 months); Centers for Disease Control and Prevention, “How Much and How Often to Feed Infant Formula” (cdc.gov, updated April 21, 2026: 8 to 12 feedings a day at first, every 3 to 4 hours later, vitamin D at 32 oz). This page is not endorsed by the AAP or the CDC. Related: baby growth percentile calculator, adjusted age calculator, Apgar score, sleep calculator.

For general information only — not medical advice. Talk with your baby’s pediatrician about how much and how often your baby should eat. How we check our calculators.