Your 3 Month Old: Milestones, Sleep, and Feeding

By The LEELALU Research Desk · Published July 22, 2026 · Every claim below links to its primary source · How we work

The short version: Your baby has discovered their hands and has started answering you with coos and gurgles. Nights often stretch out this month, and daily fussing is on its way down. Days begin to follow a loose rhythm of feeding, play, and sleep. The ranges below are wide on purpose, because every baby moves at their own pace.

What your baby is doing now

The star of month 3 is a pair of hands. Many babies find their own hands around now and study them with real focus. Babies start using their hands and eyes in coordination around 2 months. [1] Looking at their hands with interest and bringing hands to the mouth are milestones that most babies (75 percent or more) reach by 4 months, which puts this month right in prime hand watching season. [2]

The other big story is sound. By the second or third month, your baby may start "talking" back with soft coos and gurgles. [1] At about 2 months, infants may begin cooing and repeating vowel sounds like ah-ah-ah and ooh-ooh-ooh. When you answer and then pause, your baby learns that talk goes both ways. These first conversations teach the subtle rules of communication, such as taking turns and matching pace. [3]

Socially, the early grins have turned into the real thing. By the second month, those first expressions become genuine signals of pleasure and friendliness. Your baby spends much of each day watching and listening to the people around them, learning who comforts them and who helps them feel safe. If your baby sometimes smiles past you without meeting your gaze, that is normal too. Looking away gives them a little control and protects them from feeling overwhelmed, and they will hold your gaze longer as the weeks pass. [4]

Tummy time is building real strength

Keep tummy time going, always with your baby awake and watched. The AAP suggests working up to 15 to 30 minutes a day by around 7 weeks, and older, stronger babies need even more time on their tummies to build the muscles they will later use for sliding on their bellies and crawling. [5] The payoff is close: pushing up onto elbows and forearms during tummy time is a milestone most babies reach by 4 months. [2]

If your baby had long fussy evenings, this is the month the curve bends. Daily fussing typically peaks at about 3 hours a day by 6 weeks, then declines to 1 or 2 hours a day by 3 to 4 months of age. [6]

Not sure about your exact week?

Type your child's birthday, get your exact week. Free, no signup.

Open the week calculator

Sleep at this age

Sleep is still heavy but starting to organize. During the first year of life, it is common for babies to take 1 to 4 naps a day, each lasting 30 minutes to 2 hours. Night stretches lengthen too: by age 4 months, your child might sleep for up to 8 to 9 hours at a time. [7]

The NHS describes 3 to 6 months as the period when babies need fewer night feeds and may be able to sleep for longer. Some babies sleep for 5 to 8 hours or longer at night at this age, and not all do. Both patterns are within normal, so a baby who still wakes to feed is not behind. [8]

This is a good month to settle into a simple bedtime routine, because repeated patterns become habits. Keep the routine consistent and pleasant, and give the last nighttime feeding shortly before putting your baby to bed. [7] The NHS adds that too much excitement and stimulation just before bedtime can wake a child up again, so wind down with calmer activities as the evening ends. [8]

The safe sleep rules have not changed: back sleeping on a firm, flat surface, with a fitted sheet and nothing else in the sleep space. The AAP also recommends room sharing, meaning your baby sleeps in your room but not in your bed, for at least the first 6 months. It can decrease the risk of SIDS by as much as 50 percent. [9]

Feeding at this age

Breast milk and formula both support healthy growth, and many families use a mix. Here are the typical rhythms at this age, with data.

On average, most exclusively breastfed babies feed every 2 to 4 hours, about 8 to 12 times in 24 hours. Some still cluster feed as often as every hour at times, and some now manage a longer sleep interval of 4 to 5 hours. Babies generally take what they need at each feeding and stop when full. A content, drowsy baby after a feed is a good sign they got enough. [10]

Most formula-fed babies feed about every 3 to 4 hours at this age, and they can drink more at each feeding as they grow. Some sessions run long and others short, and that is fine. [11]

The vitamin D rule from earlier months still applies. Babies under 12 months need 400 IU of vitamin D each day. Babies fed only breast milk, or less than 32 ounces of formula a day, need over-the-counter vitamin D drops, because formula is fortified and breast milk usually does not provide enough on its own. [12]

This month's checklist

When to call your doctor

Most of what you see at 3 months is normal. A few signs deserve a call, so you never have to wonder.

A rectal temperature of 100.4 F (38 C) or higher in a baby younger than 3 months (12 weeks): call your doctor right away. At any age, call if the temperature rises above 104 F (40 C) repeatedly, or if a fever lasts more than 24 hours in a child under 2. [13]

Fever alongside breathing difficulty or an unexplained rash: call your doctor. If your baby is struggling to breathe or it feels like an emergency, call 911. [13]

Fewer than six wet diapers in a day, a parched dry mouth, fewer tears when crying, or a sunken soft spot on the head: these are warning signs of dehydration, and the AAP advises notifying the pediatrician immediately if any of them develop. [14]

A baby who does not smile at people or does not react to loud sounds: most babies do both by 2 months, so it is worth raising now rather than waiting. [15] The CDC's advice is direct: if your child is not meeting milestones or has lost skills they once had, do not wait. Talk with your child's doctor and ask about developmental screening. [2]

Crying that intensifies and lasts throughout the day or night: colicky behavior can also signal a medical problem such as a hernia or an illness, so it is worth a call to be checked. [6]

Leelalu is education, not medical care. Nothing here is a diagnosis. For anything on this list, or any symptom that worries you, contact your provider. If it feels like an emergency, call 911.

What comes next

Month 4 delivers some favorites. By 4 months, most babies hold their head steady without support when held, chuckle when you try to make them laugh, swing their arms at toys, and push up onto elbows and forearms during tummy time. The CDC publishes a free 4 month milestone checklist and a Milestone Tracker app you can use before the 4 month checkup. [2]

The sounds keep growing too. By 4 months, many infants babble routinely, amusing themselves for long periods with new sounds like muh-muh and bah-bah, and they become more sensitive to your tone of voice. Keep narrating your day together. Your baby is learning from your voice when a feed, a walk, or a nap is coming. [3]

Quick answers

How much should a 3 month old sleep?

Totals vary widely from baby to baby. During the first year, 1 to 4 naps a day of 30 minutes to 2 hours each is common, and by age 4 months some babies sleep up to 8 to 9 hours at a time at night. [7] The NHS notes that at 3 to 6 months some babies sleep 5 to 8 hours or longer at night, and not all do. Both patterns are normal. [8]

How often should a 3 month old eat?

Most exclusively breastfed babies feed every 2 to 4 hours, about 8 to 12 times in 24 hours, sometimes with a longer sleep interval of 4 to 5 hours. [10] Most formula-fed babies feed about every 3 to 4 hours at this age. Both patterns are normal. [11]

Why does my baby stare at their hands?

They just found them. Looking at their hands with interest and bringing hands to the mouth are milestones most babies reach by 4 months, so this month sits right in prime hand watching season. [2] Hand staring is early hand-eye coordination at work, a skill babies start building around 2 months. [1]

Sources

  1. AAP healthychildren.org, Developmental Milestones: 3 Months Old
  2. CDC, Important Milestones: Your Baby By Four Months
  3. AAP healthychildren.org, Hearing and Making Sounds
  4. AAP healthychildren.org, Emotional and Social Development: Birth Through 3 Months
  5. AAP healthychildren.org, Back to Sleep, Tummy to Play
  6. AAP healthychildren.org, Colic Relief Tips for Parents
  7. MedlinePlus (NIH), Bedtime habits for infants and children
  8. NHS, Helping your baby to sleep
  9. AAP healthychildren.org, How to Keep Your Sleeping Baby Safe: AAP Policy Explained
  10. CDC, How Much and How Often to Breastfeed
  11. CDC, How Much and How Often to Feed Infant Formula
  12. CDC, Vitamin D (Infant and Toddler Nutrition)
  13. AAP healthychildren.org, Fever: When to Call the Pediatrician
  14. AAP healthychildren.org, Signs of Dehydration in Infants and Children
  15. CDC, Important Milestones: Your Baby By Two Months

LEELALU is education, not medicine. This page cannot diagnose or treat anything, and it never replaces your clinician. For anything on the "call your doctor" list, or anything that worries you, contact your provider. Found an error? Write to hello@leelalu.com and a person will read it. Our method: Editorial Standards.