Two parents at a baby group can have entirely different sleep totals to report and both have completely healthy babies. The American Academy of Sleep Medicine, the NHS, and the Lullaby Trust all give wide ranges for infant sleep precisely because the range of normal is wide. Knowing where your baby falls within that range is useful background. Knowing what to actually look at — feeding, weight, mood when awake — is what tells you whether something is off.
Healthbooq gives you sleep norms in context, with the caveats paediatricians actually use.
Sleep Norms by Age (Under 6 Months)
The numbers below are 24-hour totals — day naps plus night sleep. They reflect the consensus from the AAP, AASM, and NHS sleep guidance.
Newborn (0–4 weeks): 14–17 hours, sometimes up to 19- Night: 8–9 hours, but in 2–3-hour stretches with feeds
- Day: 6–8 hours across 4–6 short naps
- No day-night rhythm yet — circadian rhythm doesn't start consolidating until around 6 weeks
- One longer night stretch may emerge — 4 hours, occasionally 5
- 3–5 day naps, ranging from 30 minutes to 2 hours
- Total day sleep starting to drop slightly as wakefulness lengthens
- Night sleep starting to consolidate; most parents now report 2–3 wakings (instead of 4–5)
- 3–4 day naps, often 30–90 minutes each
- The "4-month sleep regression" sits in this window — total sleep doesn't drop, but it gets noisier
- Some babies producing 5–8-hour overnight stretches; many still waking 1–2 times for feeds
- 3 day naps emerging as the typical pattern, each 1–1.5 hours
- Total sleep continues a slow drift downward
Why the Number Goes Down
Total sleep doesn't shrink because the baby needs less rest. It shrinks because sleep gets more efficient. Newborn sleep is roughly 50% active (REM-like) sleep — more cycles, more wakings between cycles, more time padding the day with naps to compensate. By 6 months, REM proportion has dropped closer to adult levels, sleep cycles are longer and quieter, and the same restorative work happens in fewer hours.
When Sleep Numbers Are Worth a Closer Look
Both ends of the range can be normal. But certain patterns are worth flagging — not because the hours are wrong, but because they may signal something underlying.
Possibly under-sleeping:- Showing tired cues (yawning, eye-rubbing, fussing, looking away) before reaching age-typical wake windows
- Cranky and inconsolable when awake; can't manage a calm wake window
- Falling asleep mid-feed every feed (in babies past the early newborn weeks)
- Total under 12 hours per 24 in a baby under 4 months, with poor weight gain
- Routinely sleeping more than 18–19 hours per 24 past the first 2 weeks
- Genuinely difficult to wake for feeds
- Poor weight gain
- Persistent jaundice or unusual lethargy
The second list is more important than the first. A consistently sleepy newborn who isn't feeding well needs to be seen — early on, this can be the only sign of feeding difficulty, infection, or jaundice serious enough to need treatment.
What Actually Tells You Things Are Going Well
Sleep hours are one input, not the headline. Paediatricians at well-baby checks weight more heavily:
- Weight gain following a steady percentile line on the growth chart
- 6+ wet nappies a day after the first week
- Alert, engaged periods when awake (even short ones)
- Reaching motor and social milestones roughly on schedule — eye contact, social smiling by 6–8 weeks, head control improving by 12 weeks
If those are in good shape, your baby is sleeping enough — whatever the number is. If they aren't, the conversation isn't really about sleep.
Key Takeaways
Babies under six months sleep a lot — between 12 and 17 hours in 24, depending on age — but the spread between healthy individuals is enormous. The 'is my baby sleeping enough?' question is best answered not by counting hours but by checking weight gain, alertness when awake, and feeding. A baby at 12 hours of sleep who's gaining weight and engaging with the world is fine. A baby at 17 hours who's hard to rouse and feeding poorly isn't.
