It is the question every exhausted parent types into a search bar at 3 a.m.: when do babies start sleeping through the night? The honest answer is earlier than you hope — but “sleeping through the night” means something different to a baby than it does to you. Here is what the evidence and real experience actually say.
What “Sleeping Through the Night” Really Means
For babies, “sleeping through the night” is defined in research as a single stretch of 5–6 hours of unbroken sleep — not the full 8 hours adults expect. By that definition, most babies reach this milestone between 3 and 6 months of age, with many manage it around 4 months. A smaller number of babies get there by 8–12 weeks, while others take 9–12 months. All of these are normal.
What actually happens: babies’ sleep cycles are short (about 50 minutes for newborns, lengthening as they grow). The milestone is not about needing less sleep — it is about learning to connect cycles without waking fully and crying for help.
Why Age and Weight Matter
Sleeping longer stretches is tied to development, not just age. Around 3–4 months, babies begin producing melatonin, the sleep hormone, and many can go 5+ hours without a feed — especially once they weigh around 5 kg (about 11 lb), when they can physically store enough milk to last. Babies who still need night feeds at 6–7 months are not behind; every child develops at their own pace.
What Helps Babies Sleep Longer Stretches
1. Distinguish day from night from birth
Keep days bright and active and nights dark and calm. This helps the developing circadian rhythm arrive sooner.
2. Put them down drowsy but awake
This is the single most effective habit. A baby who always falls asleep in your arms must recreate those conditions at every cycle transition. One who falls asleep in the cot can self-settle back to sleep when they stir.
3. Build a consistent bedtime routine
Bath, feed, book or lullaby, cot — in the same order every night. Babies read patterns far earlier than they read books. Our sample bedtime routine for a 3-month-old gives you a template to start with.
4. Feed well during the day
Frequent, full daytime feeds (and a dream feed around 10–11 p.m.) can reduce genuine hunger at night, letting sleep ability — not hunger — decide when they wake.
What About Twins or Co-Sleeping Families?
Parents of twins often find the babies develop at slightly different rates — one may sleep 6-hour stretches at 3 months while the other still wakes every 3 hours. That is completely normal and not something to fix. Co-sleeping families (following safe sleep guidance) sometimes report earlier long stretches simply because the baby stirs and resettles without fully waking. Wherever your baby sleeps, keep the sleep surface firm, flat, and clear of loose bedding.
Common Setbacks Are Normal
Expect regressions around 4 months (when sleep cycles permanently mature) and again around 8–10 and 18 months. Illness, teething, travel, and milestones like crawling or standing temporarily break sleep too. A baby who slept through for a month and suddenly wakes hourly is not broken — they are developing.
When to Talk to Your Paediatrician
- Your baby snores loudly or seems to stop breathing during sleep
- They cannot sleep for more than 2 hours by 6 months despite full daytime feeds
- You are concerned about weight gain or feeding
So: most babies sleep through the night — in baby terms — between 3 and 6 months. It is a developmental milestone, not a training achievement, and the calmest path there is consistent routines, drowsy-but-awake practice, and patience. The 3 a.m. wakes will end; they always do.
