Most babies start sleeping through the night between 3 and 6 months of age, though “sleeping through the night” may not mean what you think. In pediatric terms, it refers to a stretch of about 5 to 8 consecutive hours, not a full 10 or 12 hours of uninterrupted sleep. By 6 months, roughly half of all babies are sleeping 5 or more hours straight. The other half aren’t there yet, and that’s normal too.
What “Sleeping Through the Night” Actually Means
New parents often picture a baby who falls asleep at 7 p.m. and doesn’t make a sound until morning. That’s not the benchmark pediatricians use. A baby who sleeps 6 to 8 hours without waking for a feeding counts as sleeping through the night. A baby who goes down at 10 p.m. and wakes at 4 a.m. has technically hit the milestone, even though it won’t feel that way to a sleep-deprived parent.
Even babies who have reached this milestone will still wake briefly between sleep cycles. The difference is that they can settle themselves back to sleep without needing you to feed, rock, or soothe them. That self-settling ability is what really separates a baby who “sleeps through the night” from one who doesn’t.
The Biology Behind the Timeline
Two things need to happen before a baby can sleep long stretches: their internal clock needs to develop, and their stomach needs to be big enough to hold them through the night without a feeding.
Babies don’t produce their own melatonin, the hormone that signals nighttime sleepiness, until around 8 weeks of age. Before that point, they literally lack the biological machinery for a predictable day-night rhythm. This is why newborns sleep in short bursts around the clock with no regard for whether the sun is up.
The weight threshold matters just as much. Babies generally need to weigh at least 12 to 13 pounds before they can go 6 to 8 hours without needing calories. Most reach that weight somewhere between 3 and 4 months, though bigger babies at birth may get there sooner. Before a baby hits that weight, waking to eat isn’t a sleep problem. It’s a caloric necessity.
A Realistic Month-by-Month Picture
During the first two months, expect feedings every 2 to 3 hours, day and night. Sleep stretches rarely exceed 3 to 4 hours. This is the hardest phase, but it’s also the shortest.
Between 3 and 4 months, many babies begin consolidating their nighttime sleep into one longer stretch, often 4 to 6 hours, with one or two additional wake-ups for feeding. This is when you’ll likely see the first hints of a pattern. However, around the 4-month mark, a well-known shift in sleep architecture occurs. Babies transition from newborn-style sleep to more adult-like sleep cycles, which can temporarily make things worse before they get better.
By 6 months, about 50% of babies sleep 5 or more hours continuously. Nighttime feedings start decreasing around months 6 and 7. By 8 to 9 months, most babies no longer need nighttime feeds from a nutritional standpoint, and their daytime intake of breast milk, formula, and solid foods covers their caloric needs.
Between 10 and 12 months, the expectation is no nighttime feeds and longer consolidated sleep. But even at this age, some babies still wake. The waking is rarely about hunger at this point; it’s more often about comfort, habit, or developmental disruption.
How Feeding Method Affects Sleep
There’s a widespread belief that formula-fed babies sleep longer stretches sooner because formula takes longer to digest. The reality is more nuanced. A large study of over 4,500 infants from the Tongji Maternal and Child Health Cohort found that exclusively breastfed babies actually had longer total sleep durations at 3, 6, and 12 months compared to babies who were partially or fully formula-fed. The non-exclusively breastfed group was more likely to follow shorter overall sleep patterns.
That said, breastfed babies may wake more frequently for individual feedings since breast milk digests faster. The distinction is between total sleep time (breastfed babies may get more of it) and the length of each uninterrupted stretch (formula-fed babies may have slightly longer blocks). Neither feeding method guarantees an early sleeper, and switching to formula specifically to improve sleep isn’t supported by the evidence in the way many parents hope.
Sleep Regressions and Setbacks
Even after your baby starts sleeping longer stretches, expect temporary setbacks. These regressions aren’t really about age alone. They’re tied to what your baby is going through developmentally.
The most common disruption hits around 4 months, when sleep cycles mature and reorganize. A baby who had been sleeping 5 or 6 hours straight may suddenly start waking every 2 hours again. This is frustrating, but it’s a sign of neurological development, not a step backward.
When babies learn new motor skills like rolling, crawling, or pulling to stand, they often want to practice those skills constantly, including in the middle of the night. They may also get stuck in positions they can’t get out of independently, which leads to crying and needing your help. These disruptions are temporary and typically resolve within a week or two once the skill is mastered.
Around 9 months, separation anxiety peaks. A baby who was sleeping independently may suddenly protest being put down or wake up distressed when they realize you’re not there. This is a healthy emotional milestone, but it can wreck a sleep routine for a few weeks.
What You Can Do to Help
You can’t force a baby to sleep through the night before they’re biologically ready, but you can set the stage. Start by reinforcing the difference between day and night early on. Keep daytime feedings bright and social, and nighttime feedings dim and boring. This helps support their developing circadian rhythm once melatonin production kicks in around 8 weeks.
Putting your baby down drowsy but awake, rather than fully asleep, gives them the chance to practice falling asleep on their own. This is the single most important skill for sleeping through the night, because every baby wakes between sleep cycles. The ones who “sleep through” are simply the ones who can drift back off without help.
For safe sleep, place your baby on their back in their own sleep space with a firm, flat mattress and a fitted sheet. Keep the crib free of blankets, pillows, stuffed animals, and bumper pads. Room-sharing without bed-sharing is the safest arrangement during the first several months.
When Longer Stretches Still Aren’t Happening
If your baby is past 6 months, gaining weight well, eating enough during the day, and still waking multiple times a night, the issue is more likely a sleep association than a physical need. Sleep associations are habits your baby links to falling asleep: nursing, rocking, being held, or using a pacifier. When they wake between sleep cycles (which all humans do), they need that same condition recreated to fall back asleep.
Various approaches exist for teaching independent sleep, ranging from gradual methods where you slowly reduce your involvement over days or weeks, to more direct approaches where you give the baby space to figure it out with periodic check-ins. No single method works for every family, and the best approach depends on your baby’s temperament and your own comfort level. Most babies respond to consistent changes within 3 to 7 nights.
Some babies, particularly those with reflux, food sensitivities, or ear infections, wake frequently because of discomfort rather than habit. If your baby seems to be in pain when waking, or if sleep hasn’t improved despite consistent routines, it’s worth exploring whether something physical is contributing.