Most babies start sleeping through the night somewhere between 3 and 6 months old, but the range of normal is wide. By 6 months, roughly half of infants can sleep 8 consecutive hours without needing a parent’s help. The other half take longer, and many healthy babies continue waking at night well past their first birthday.
Part of the confusion around this milestone is what “sleeping through the night” actually means. In sleep research, it typically means 6 to 8 hours of uninterrupted sleep, not the 10 or 12 hours adults sometimes expect. And a baby who “sleeps through” is not necessarily sleeping without waking at all. They’re waking briefly and falling back to sleep on their own, without crying or needing to be fed or held.
What Happens in the First 4 Months
Newborns don’t have the biological wiring for long stretches of sleep. Their internal clocks haven’t developed yet, and they cycle between sleep and waking around the clock in short bursts. Babies don’t develop regular sleep cycles until about 4 months of age. Before that point, any long stretch of nighttime sleep you get is essentially luck, not a pattern you can count on.
Newborns also have tiny stomachs that empty quickly, especially when breastfed. Frequent night feedings in the first few months aren’t a sleep problem. They’re a nutritional necessity. Trying to push longer sleep stretches before a baby is physically ready can interfere with healthy weight gain.
The 3 to 6 Month Window
Around 3 months, many babies begin sleeping 6 to 8 hour stretches at night. This is when the brain starts producing more predictable sleep-wake cycles, and the body can go longer between feedings. It’s the earliest point where “sleeping through the night” becomes a realistic possibility for some families.
By 6 months, about 53% of infants can manage 8 consecutive hours of sleep, according to a review of infant sleep studies published in BMJ Open. That means just over half. If your 6-month-old is still waking, you’re in perfectly normal company. Bottle-fed babies tend to drop night feedings earlier, often around 6 months, while breastfed babies frequently still need at least one night feeding until closer to 12 months. Breast milk digests faster than formula, so breastfed babies genuinely get hungry sooner.
Why Some Babies Take Longer
Infant sleep consolidation is better understood as a gradual process than a single milestone. Researchers describe significant individual variability in how quickly babies learn to string together longer sleep periods. Two healthy babies born on the same day, in similar environments, with similar routines, can have very different sleep patterns for months.
Several things can interrupt or delay the process:
- Growth spurts temporarily increase hunger, adding extra night feedings even after a baby had dropped them.
- New motor skills like rolling over or pulling up can keep babies awake as they practice in the crib.
- Teething pain causes nighttime waking and crying, often unpredictably.
- Illness or routine changes such as travel, starting daycare, or a cold can reset sleep patterns for days or weeks.
- Separation anxiety, which peaks around 9 months, can make a baby who previously slept well start crying when a parent leaves the room.
These disruptions are sometimes called sleep regressions. They’re temporary, but they can feel like a major setback when you thought you’d turned a corner.
Sleep Regressions to Expect
The most talked-about regression happens around 4 months. This is when a baby’s sleep architecture shifts from newborn-style sleep to more adult-like cycles, with lighter sleep stages that make waking easier. Ironically, this brain maturation is what eventually allows consolidated nighttime sleep, but in the short term it often makes things worse.
Another common rough patch hits around 8 to 10 months, driven largely by separation anxiety and new physical milestones like crawling or standing. Babies at this age are more aware of their surroundings and more distressed when a parent isn’t visible. A third regression sometimes appears around 12 months, often tied to the transition from two naps to one or the excitement of learning to walk.
Each regression typically lasts 2 to 4 weeks. They don’t mean your baby has permanently lost the ability to sleep well. They mean the brain is doing something new, and sleep temporarily takes a hit.
Helping Your Baby Build Sleep Skills
Before 4 months, there isn’t much you can do to shape sleep patterns. The brain simply isn’t ready. Focus on keeping nights dark and quiet and daytime bright and social so your baby starts learning the difference.
Starting around 4 months, you can begin putting your baby down drowsy but awake. This single habit is the foundation of independent sleep. A baby who falls asleep in your arms and wakes up in a crib doesn’t know how they got there, and they’ll cry for you to recreate the conditions they fell asleep in. A baby who falls asleep in the crib learns that waking up there is normal and expected.
When your baby fusses at night, pausing briefly before responding gives them a chance to resettle on their own. This doesn’t mean ignoring prolonged crying. It means giving a few minutes of space before assuming they need you. Many babies make noise during the transition between sleep cycles and will drift back off if given the opportunity.
Consistent bedtime routines also help. A predictable sequence of events (bath, feeding, book, bed) signals to the brain that sleep is coming. Keep the routine short, around 20 to 30 minutes, and do it in the same order each night.
What “Normal” Actually Looks Like
If your baby is 8 or 9 months old and still waking once or twice a night, that falls within the normal range, particularly for breastfed babies. If your 4-month-old suddenly started sleeping 7-hour stretches, that’s also normal. The variation between individual babies is enormous, and comparing your child’s sleep to another family’s experience is rarely useful.
The most important reframe is this: a “good sleeper” at any age is not a baby who never wakes up. Every human, infant or adult, wakes briefly between sleep cycles throughout the night. A good sleeper is a baby who can fall back to sleep without needing you to intervene every time. That skill develops gradually, and for most babies it clicks into place somewhere between 4 and 12 months, with plenty of bumps along the way.