When Do Babies Sleep Through the Night? The Truth About Sleep Milestones
You’ve probably Googled it at 3 a.m., bleary-eyed and desperate: “When will my baby finally sleep through the night?” The internet’s answers range from “any day now” to “not until kindergarten,” and if you’re anything like most parents I work with, that rollercoaster of advice leaves you more confused (and exhausted) than before.
The truth? There isn’t one universal age when babies suddenly stop waking. “Sleeping through the night” isn’t even a single, agreed-upon milestone (spoiler: many studies count just five hours as “through the night”). But there are predictable patterns, developmental changes, and practical things you can do to help your baby move toward longer, more restful stretches.
Let’s break down what science actually says, what’s normal at different ages, and how you can support healthy night sleep without rigid rules, or “cry it out” if that’s not your path.
What “sleeping through the night” actually means (and why the definition matters)
Before we talk timelines, let’s get clear on the term itself. Adults wake briefly multiple times a night; babies do, too. What parents really want is a baby who can link those sleep cycles without needing you to fully intervene each time.
Researchers often define “sleeping through the night” as five to six consecutive hours. Some use six to eight hours, but that bar is higher than what many infants reach at first. For example:
A Harvard Health review found that at 6 months, about 38 % of babies still don’t make a six-hour stretch, and 57 % aren’t doing eight hours straight (Harvard Health).
ParentingScience notes that 5+ hour stretches often begin between 5–6 months, but variability is normal (ParentingScience).
If your baby isn’t giving you an eight-hour block by half a year, nothing is “wrong”- you’re still within the normal range.
A realistic timeline for night sleep consolidation
Think of night sleep like learning to ride a bike: some kids pedal off quickly, others need a slower, steadier approach. Here’s a general, research-backed framework:
0–3 months: Sleep is highly fragmented. Circadian rhythms aren’t mature, and most babies wake every 2–4 hours to feed (ParentingScience).
3–4 months: Circadian rhythm begins to develop. Some babies can stretch 4–5 hours, but growth spurts and the well-known “4-month sleep regression” can cause new night wakings (PMC).
5–6 months: Many begin linking sleep cycles and may do one 5–6 hour stretch. But feeds and wakeups are still normal, especially for breastfed babies.
7–12 months: Longer stretches (6–8 hours) are more common, though teething, illness, and separation anxiety often cause setbacks (ParentingScience).
A study in Infant Sleep and Development showed some babies sleep 8–9 hours without interruption by 4–5 months (ScienceDirect). But that’s possible, not guaranteed.
The takeaway: normal is wide. Don’t panic if your 7-month-old still wakes once or twice, especially if they feed and go back to sleep easily.
What influences when (and how) your baby sleeps through
Biological and genetic factors
Temperament: Some babies are naturally more sensitive and wake easily.
Feeding method: Breastfed babies digest faster and may wake to feed more frequently.
Sleep architecture: Babies’ brains gradually develop longer nighttime sleep cycles across the first year (PMC).
Environmental and learned factors
Light and dark cues: Morning light helps set circadian rhythm; dim evenings promote melatonin release.
Consistent routines: Predictable bedtime and nap routines support sleep consolidation.
Daytime sleep balance: Too much (or too little) day sleep can sabotage nights.
Response patterns: Babies who get a chance to resettle sometimes learn to do so on their own.
Regressions: Developmental leaps, teething, travel, and illness can temporarily disrupt night sleep—even if you’ve had a good stretch going.
Practical steps to encourage longer stretches
You can’t force your baby to hit a milestone before they’re developmentally ready, but you can set them up for success:
Create clear day-night cues. Morning light, quiet dim evenings, and a calm bedtime routine help set their internal clock.
Prioritize age-appropriate naps. Overtired babies often wake more at night.
Use a predictable bedtime routine. Feed, bath, book, song (whatever works for your family) done in the same order each night.
Consider response-based settling. If full feeds are done and baby wakes out of habit, try brief reassurance first instead of full re-rocking or feeding.
Introduce independent sleep skills early if you want. You don’t have to use cry-it-out. Gradual, hands-on methods can help babies learn to connect sleep cycles.
Anchor wake up time. Even if naps vary, aiming for a consistent wake up within 30 minutes helps set circadian rhythm.
Expect and plan for regressions. Teething, illness, or travel may mean more night wakings for a while, it doesn’t mean you’re back to square one.
What real families say about working with Heaven Sent Sleep
“Heaven Sent Sleep was extremely quick to respond to my questions and always answered them thoroughly. She helped us get him sleeping independently at night and naps… by the end I felt confident in how to support my son.”
“On our call, Lauren’s tips produced dramatic difference the very first night. It was life changing.”
“They provided amazing non-judgmental support… gave me great information on how to deal with upcoming challenges… I’m a better mom now.”
The bottom line (and why you’re not failing)
Babies don’t all follow the same sleep chart. Some do long stretches early, some take many months, and both can be normal. But you’re not powerless. You can shape routines, environment, and gentle skills that set your baby up for better sleep—and your own rest.
If you’re exhausted and unsure how to move from night waking chaos to longer stretches, you don’t have to wait it out and hope. I help families create custom, response-based sleep plans that respect your feeding goals and comfort level. See how 1:1 support works here.
