Most babies start sleeping through the night somewhere between 3 and 6 months old, though the range is wide and “sleeping through the night” rarely means a full eight hours at first. For pediatricians, the benchmark is typically a stretch of 6 to 8 hours without needing a feeding. Some babies hit this milestone at 3 months, others not until closer to 12 months, and both can be perfectly normal.
What “Sleeping Through the Night” Actually Means
New parents often picture an unbroken stretch from bedtime to morning, but that’s not what sleep researchers mean. A baby who sleeps 6 consecutive hours is generally considered to be sleeping through the night. Even adults wake briefly between sleep cycles; the difference is that older babies learn to fall back asleep on their own without crying or needing to eat. That skill, called self-soothing, is a big part of what makes longer stretches possible.
How a Baby’s Internal Clock Develops
Newborns have no sense of day versus night. Their sleep is driven entirely by hunger and fatigue, cycling in short bursts of 2 to 4 hours around the clock. Around 8 to 12 weeks, a baby’s circadian rhythm matures enough to start distinguishing daytime from nighttime. This is when the body begins producing melatonin in a predictable pattern, making nighttime sleep stretches gradually longer.
By about 3 to 4 months, many babies consolidate more of their sleep into the nighttime hours. But biological readiness alone doesn’t guarantee uninterrupted sleep. Hunger, temperament, and sleep habits all play a role in whether that potential translates into a full night.
Why Feeding Method Matters
How your baby eats has a real effect on how soon they sleep through the night. Formula-fed babies tend to sleep longer stretches earlier because formula digests more slowly, keeping them full for longer. Breastfed infants and their mothers wake up more often at night, according to systematic reviews comparing the two groups.
For formula-fed babies, night feeds often become unnecessary around 6 months of age. At that point, waking is more likely habit than hunger. For breastfed babies, the timeline is longer. Healthy breastfed children can typically be night-weaned from around 12 months. This doesn’t mean breastfed babies can’t sleep through the night before then. Many do. But the biological need for nighttime calories can persist longer.
If your baby is taking less than about 60 ml (2 ounces) during a night feeding, that feed is more for comfort than nutrition, and you can consider dropping it and resettling with other soothing techniques. For larger feeds, a gradual reduction over 5 to 7 nights tends to work better than stopping abruptly.
The 4-Month Sleep Regression
Just when many parents think they’ve turned a corner, sleep often falls apart around 4 months. This is the most well-known sleep regression, and it happens because a baby’s sleep architecture permanently changes. They shift from newborn-style sleep into more adult-like cycles with lighter stages, which means more opportunities to wake up between cycles.
Sleep regressions are periods of worse sleep lasting roughly two to four weeks. They’re common throughout the first year and beyond. Another notable disruption hits around 9 months, often fueled by separation anxiety. A baby who was sleeping through the night may suddenly start crying when you leave the room. These setbacks are temporary, though they rarely feel that way at 2 a.m.
When Sleep Training Can Help
Babies are often ready for sleep training around 4 months old. The goal isn’t to eliminate all nighttime needs but to help a baby learn to fall asleep independently, so when they naturally wake between sleep cycles, they can settle back down without intervention.
The most common approaches range from gradually reducing your presence in the room over several nights to letting your baby work through fussiness on their own. The latter is harder on parents but often produces results within a night or two. No single method works for every family, and the best one is the one you can stick with consistently.
Sleep training doesn’t mean ignoring hunger. If your baby still needs nighttime feeds based on their age and weight, those continue. The training addresses the falling-asleep process, not the feeding schedule.
A Realistic Timeline by Age
- 0 to 2 months: Sleep comes in 2- to 4-hour blocks around the clock. Night and day are meaningless to your baby. This is survival mode for everyone.
- 2 to 3 months: The circadian rhythm starts kicking in. You may notice one longer stretch at night, often 4 to 5 hours. That’s progress, even if it doesn’t feel like it.
- 3 to 6 months: The window where many babies first sleep 6 or more consecutive hours. Formula-fed babies tend to reach this earlier in the range, breastfed babies later.
- 6 to 9 months: Most babies are physically capable of sleeping through the night without a feed. Whether they actually do depends on sleep habits, temperament, and whether they’ve learned to self-soothe.
- 9 to 12 months: Separation anxiety can cause new night waking even in babies who were previously sleeping well. This usually resolves within a few weeks.
What You Can Do Right Now
A consistent bedtime routine helps signal to your baby’s developing brain that sleep is coming. Bath, feeding, dim lights, and a quiet room in the same order each night creates predictable cues. Starting this pattern early, even before your baby is developmentally ready to sleep through the night, builds the foundation.
Room-sharing for at least the first 6 months is recommended by the American Academy of Pediatrics for safety. Keep the sleep surface firm and flat, with no blankets, pillows, or soft toys. Offering a pacifier at bedtime is associated with safer sleep, and if you’re breastfeeding, you can introduce one after breastfeeding is well established.
Exposure to natural light during the day and keeping nighttime interactions boring (dim lights, minimal talking, no play) reinforces the circadian rhythm as it develops. The more clearly you differentiate day from night in your baby’s environment, the faster their internal clock catches up.