Most babies are physically capable of sleeping through the night somewhere between 4 and 6 months of age, though many don’t consistently do so until closer to 9 or 12 months. There’s no single “right” age, because sleeping through the night depends on a combination of brain development, feeding needs, and temperament that varies from baby to baby.
It also helps to clarify what “sleeping through the night” actually means. Pediatric sleep researchers typically define it as a stretch of 6 to 8 hours without needing a feeding or caregiver intervention. That’s not the same as an adult sleeping 8 to 10 uninterrupted hours. Even babies who “sleep through” often wake briefly and put themselves back to sleep without you ever knowing.
Why Young Babies Can’t Sleep Long Stretches
Newborns aren’t wired for consolidated nighttime sleep. Their internal clock, the system that tells the body when it’s day and when it’s night, doesn’t start functioning until the end of the newborn period. Melatonin production, the hormone that signals darkness and sleepiness, begins around that same time. Recognizable patterns of sleeping during the night and being awake during the day start to emerge at 2 to 3 months.
That internal clock continues maturing for much longer than most parents expect. It starts becoming stable between 6 and 18 months, and the full system isn’t considered established until around age 1.5 to 2 years. This is one reason sleep can feel like a moving target during the first year: your baby’s brain is still building the biological machinery that makes predictable sleep possible.
Stomach size also plays a role. Young infants have tiny stomachs and digest breast milk or formula quickly, so they genuinely need to eat every few hours around the clock. As they grow and can take in more calories during the day, the nutritional need for nighttime feedings gradually fades.
A Realistic Timeline by Age
At 0 to 3 months, expect sleep in short bursts of 2 to 4 hours, day and night. Newborns need frequent feedings and haven’t yet developed any circadian rhythm. There is nothing you can or should do to push longer stretches at this stage.
Between 3 and 4 months, many babies begin offering one longer stretch at night, sometimes 4 to 6 hours. This is when parents often get their first taste of more continuous sleep. It’s also when the so-called 4-month sleep regression can hit: your baby’s sleep architecture is reorganizing from newborn patterns into more adult-like cycles, which can temporarily make sleep worse before it gets better.
From 4 to 6 months, babies become developmentally ready to sleep longer stretches. The American Academy of Pediatrics notes that by 6 months, babies should be able to go at least 6 hours at night without a feeding, and that nighttime feedings can be stopped by that age. Many pediatricians consider 4 months the earliest appropriate age to begin encouraging self-soothing skills.
Between 6 and 12 months, most healthy babies can sleep 6 to 8 hours or more at a stretch. That said, temporary disruptions are common. Around 8 to 10 months, separation anxiety ramps up, and new physical skills like pulling to stand can make babies restless. Near 12 months, another regression often surfaces, driven by increased activity, teething, heightened emotional development, and the adjustment to changing nap schedules.
Breastfed Babies Wake More, But Sleep More Overall
One of the most persistent pieces of advice new parents hear is that formula-fed babies sleep better. The reality is more nuanced. Research tracking infant sleep patterns over time found that fully breastfed babies do wake more often at night, particularly between 6 and 12 months. But those same breastfed infants actually logged longer total nighttime sleep and longer total sleep overall compared to formula-fed babies, from 3 months through 24 months.
Partially breastfed babies, those getting a mix of breast milk and formula, showed sleep patterns similar to fully breastfed babies rather than formula-fed ones. So switching to formula or adding a bottle before bed is unlikely to be the fix for nighttime wakings that some parents hope for. Breastfed babies may simply need a brief feeding to resettle, but they’re not getting less sleep because of it.
When and How Sleep Training Fits In
Sleep training, broadly, means helping your baby learn to fall asleep independently rather than relying on feeding, rocking, or being held. The HealthyChildren.org guidelines from the American Academy of Pediatrics suggest that babies 4 months and older can begin learning this skill. The core principle is straightforward: put your baby down when they’re drowsy but still awake, so they practice the transition from wakefulness to sleep on their own.
This also means giving babies a moment before responding to every cry. Babies cycle between light and deep sleep, and brief fussing between cycles is normal. If you rush in immediately, your baby doesn’t get the chance to learn that they can settle without help. That doesn’t mean ignoring prolonged distress. It means pausing briefly to see if they resettle on their own.
There are many specific approaches to sleep training, ranging from very gradual methods where you slowly reduce your presence in the room to more direct methods where you leave the room and check in at intervals. No single method is universally best. What matters most is consistency: picking an approach and sticking with it long enough for your baby to learn the new pattern, which typically takes 3 to 7 nights.
Setting Up the Sleep Environment
A safe, consistent sleep space helps signal to your baby that it’s time for a long stretch. The sleep surface should be firm, flat, and level, covered only with a fitted sheet. That means no pillows, blankets, stuffed animals, crib bumpers, or weighted swaddles. Soft items, loose bedding, and anything weighted pose suffocation risks.
Room sharing, where your baby sleeps in a crib or bassinet in your room but not in your bed, may reduce the risk of SIDS by as much as 50% compared to bed-sharing or sleeping in a separate room. It also makes nighttime feedings and check-ins easier, since you can respond without fully getting out of bed. Car seats, strollers, and bouncy seats are not safe for regular sleep. If your baby dozes off in one, move them to their crib as soon as you can.
What “Normal” Really Looks Like
Parents often feel pressure when other families report their baby sleeping through the night at 8 weeks. Some babies genuinely do this early, and some don’t reliably sleep long stretches until well past their first birthday. Both are within the range of normal. Studies consistently show wide variation in when babies consolidate their nighttime sleep, and a baby who wakes once or twice at night at 9 months is not behind developmentally.
Sleep regressions are also normal and temporary. They tend to cluster around developmental leaps: when your baby is mastering a new skill like rolling, crawling, or walking, their brain is so active that sleep gets disrupted for a week or two. This is frustrating but not a sign that something has gone wrong. The pattern you had before usually returns once the new skill is consolidated.
If your baby is older than 6 months, can’t sleep at least 6 hours without a feeding, and this pattern isn’t improving, it’s worth raising with your pediatrician. In most cases, the issue is a habit (like feeding to sleep) rather than a medical problem, and small changes to the bedtime routine can make a significant difference.