The rule of thumb
About 2.5 oz per pound a day, up to about 32 oz
Newborns take 1–2 oz per feed, 8–12 times a day. At 1 month that's about 3–4 oz a bottle, at 2 months 4–5 oz, at 4–5 months 5–7 oz. The calculator works it out for your baby's exact age and weight; the full chart by month is below.
Your day and night feeding rhythm
- Per feed: 2½–3 oz (70–90 ml) of formula, 7–8 times a day.
- Per day: about 19–23 oz (560–690 ml).
- At night: around the clock.
- Breastfed: nurse on cue, and watch diapers and growth, not ounces; a pumped bottle is about 2–2½ oz (55–75 ml).
- The real test: plenty of wet diapers, growth along their own curve and a baby who is content after feeds.
How much a 3-week-old drinks
| Per feed | Feeds a day | Per day | Night feeds | |
|---|---|---|---|---|
| Formula | 2½–3 oz (70–90 ml) | 7–8 | 19–23 oz (560–690 ml) | around the clock |
| Breast milk in a bottle | 2–2½ oz (55–75 ml) | 8–12 | about 25 oz (750 ml), typically 19–30 oz | around the clock |
Compared with 2 weeks: about ½ oz more per bottle, about the same number of feeds. For a baby of typical weight (9 lb, WHO median). A heavier baby drinks a little more, a lighter one a little less: about 2½ oz per pound a day (about 165 ml per kg), rarely more than about 32 oz (960 ml) in 24 hours (AAP). The calculator above does it for your baby's weight. Night feeds are a typical picture, not a target: babies vary a lot.
What's different at this age
The 3-week growth spurt. Around 3 weeks (and again around 6 weeks) many babies want to feed more often for a few days. The Czech national breastfeeding guide lists 3 and 6 weeks, then 3 and 6 months, as typical spurts, when a breastfed baby may nurse 12–15 times a day, and says this is not a sign of too little or poor milk (SZÚ). It's commonly reported rather than precisely measured, so your baby's version may come a little earlier or later, or hardly show.
For a bottle-fed baby: offer a little more when you see hunger cues, and stop when they turn away. A few hungrier days don't mean the formula is wrong; talk to your pediatrician before switching.
More isn't always hunger. Babies also suck for comfort. Signs of too much are stomach pain, gas, spitting up or vomiting after feeds (AAP). If your baby seems to want to eat all the time, even when full, call your pediatrician (AAP).
Night feeds
Feeds still run around the clock, usually every 2½ to 3½ hours. A formula-fed baby may give you one longer stretch of 4 hours; in the first weeks, if they sleep longer than 4–5 hours and start missing feeds, wake them (AAP).
Breastfed babies: what to watch instead of ounces
At the breast there is nothing to count, and you don't need to. Breastfed babies feed on cue, typically 8–12 times a day in the early months (AAP); in one study of 1–6-month-olds the range was 6 to 18 feeds a day, and how often a baby fed said nothing about how much milk their mother made (Kent 2006). Watch the signs below instead. For a bottle of pumped milk, plan on about 25 ounces (750 ml) a day divided by the number of feeds: this amount hardly changes from 1 to 6 months (KellyMom).
Is my baby getting enough?
- Wet diapers: 6 or more a day, pale and not smelly (AAP).
- Growth along their own curve on the WHO charts (AAP). Our growth percentile calculator shows where your baby sits; the curve matters more than the number.
- Content after most feeds: relaxed hands, settled for a while (CDC).
Hungry or full? Paced bottle feeding
Hungry: hands to mouth, turning toward the breast or bottle, puckering, smacking or licking lips, clenched hands (CDC). Crying is a late sign. Full: closes their mouth, turns away from the breast or bottle, relaxes their hands (CDC).
Paced bottle feeding lets your baby set the speed: hold them fairly upright, keep the bottle closer to horizontal so milk flows only while they suck, and pause every few minutes (Kassing 2002). The NHS puts it simply: be guided by your baby, give them plenty of time and don't force them to finish. Leftover milk means it worked.
When to call the doctor
- Fever of 100.4 °F (38 °C) or more under 3 months: call right away (AAP).
- Signs of dehydration: fewer wet diapers, a sunken soft spot, few or no tears, drowsiness (NHS).
- Vomiting a lot, forcefully, or a baby who seems in pain (NHS).
- Wants to eat all the time, even when full, or has trouble gaining weight (AAP).
Trust your instinct: if your baby seems unwell, call, whatever the numbers say.
Born early? Use the corrected age for the number of feeds and for starting solids, and real weight for the amounts. Our corrected age calculator works it out.
Questions
How much should a 3 week old eat per feeding?
Usually 2½ to 3 ounces (70–90 ml) of formula per feed, 7 or 8 times in 24 hours. Breastfed babies nurse on cue, typically 8–12 times a day (AAP).
Is 4 oz too much for a 3 week old?
It's above the usual range for this age. An occasional bigger bottle is fine if your baby is relaxed afterward; regular 4-ounce bottles with spitting up, gas or discomfort suggest smaller, slower feeds. If your baby always seems hungry, ask your pediatrician.
Is there a growth spurt at 3 weeks?
Many babies feed more often for a few days around 3 weeks and again around 6 weeks (SZÚ). It passes on its own; offer more when your baby shows hunger and less when they show fullness.
How much breast milk does a 3 week old need in a bottle?
About 2 to 2½ ounces (55–75 ml) per bottle. Breastfed babies' daily intake builds up over the first weeks toward about 25 ounces (750 ml) a day (KellyMom).
How many wet diapers should a 3 week old have?
Six or more a day, pale and not smelly (AAP).
Feeding by age
All ages: the baby feeding chart · the full feeding calculator · how to prepare formula safely · water and tea
Same age: weight percentiles · wake windows and naps
Sources
- American Academy of Pediatrics, HealthyChildren.org: Amount and Schedule of Baby Formula Feedings
- AAP, HealthyChildren.org: How Often and How Much Should Your Baby Eat?
- CDC: How Much and How Often to Feed Infant Formula
- NHS: Bottle feeding advice
- AAP, HealthyChildren.org: How to Tell if Your Breastfed Baby is Getting Enough Milk
- CDC: Signs Your Child is Hungry or Full
- Kassing D., Bottle-feeding as a tool to reinforce breastfeeding, Journal of Human Lactation 2002 (paced bottle feeding)
- NHS: Dehydration
- Kent J.C. et al., Volume and frequency of breastfeedings and fat content of breast milk throughout the day, Pediatrics 2006
- KellyMom: How much expressed milk will my baby need?
- Státní zdravotní ústav and Laktační liga (Czech National Institute of Public Health): Kojení, všechno, co potřebujete vědět (2023)
- AAP, HealthyChildren.org: Fever and Your Baby
- World Health Organization: Child Growth Standards, weight-for-age (the typical weights)
Spotted a mistake or an outdated figure? Write to [email protected].