A sleep approach that worked perfectly at eight weeks will almost certainly stop working at four months. What looked like excellent settling at six months may feel completely derailed by ten months. Baby sleep does not hold still — it evolves continuously across the first year as your baby’s brain, circadian rhythm, and developmental capacity all change at a remarkable pace. One of the most common sources of parent confusion and distress around sleep is applying an expectation that belongs to one age to a baby who is at a completely different developmental stage. This guide maps what sleep actually looks like, month by month across the first year, so that you know what to expect when — and what is simply your baby doing exactly what babies at that age do.

Newborn Sleep (0–6 Weeks): No Pattern Is the Pattern

A newborn’s sleep is governed by hunger, not by the clock. With a stomach the size of a marble at birth, a newborn needs to feed frequently — and sleep happens in the gaps between feeds, distributed across 24 hours with no reliable day-night distinction. Total sleep for a healthy newborn is typically 14–17 hours in 24 hours, but the distribution of that sleep is entirely unpredictable. Wake windows are very short — around 45 to 60 minutes — and a baby who has been awake longer than this will often become overtired and harder to settle.

The circadian rhythm — the internal body clock that distinguishes day from night — does not begin to develop until around six to eight weeks. Before this point, attempting to establish a day-night pattern or a predictable schedule is unlikely to produce results. The most useful approach in the newborn period is learning your individual baby’s sleep cues, respecting short wake windows, and prioritising safe sleep above everything else. This stage is genuinely hard, and it genuinely passes.

Six to Twelve Weeks: The First Shifts

Between six and twelve weeks, the circadian rhythm begins to emerge. Many parents notice that their baby starts to show a slightly longer stretch of sleep at one point in the 24-hour period — often, but not always, in the early part of the night. This is an encouraging biological development, not the result of any specific technique, and it varies enormously between babies. A simple bedtime routine introduced from around six to eight weeks — a short, consistent sequence of bath or wash, feed, and settling — begins to take on meaning as the circadian rhythm develops. Wake windows extend slightly to around 60 to 90 minutes. Total naps begin to consolidate from newborn-style frequent catnaps toward fewer, slightly longer sleep periods, though this is gradual rather than sudden.

Three to Four Months: The Most Talked-About Transition

The four-month period brings the most significant sleep change of the first year, and the one that catches most parents off guard. Around three to four months, a baby’s sleep architecture permanently changes — shifting from the newborn sleep pattern to a more mature cycle that includes full light-sleep arousal between sleep cycles, just as adults experience. This means that a baby who was previously cycling through sleep without fully waking now surfaces between cycles in a way that requires some form of settling to return to sleep.

If feeding or rocking to sleep was the settling strategy before this change, the baby will now need that same strategy to resettle between every cycle overnight. This is often experienced as a sudden dramatic worsening of sleep — and it is genuinely disruptive. It is not reversible, and it is not caused by anything the parent did or did not do. What it does mean is that this is a natural point at which to consider whether the settling approach you have been using is sustainable for the next several months, and whether gradually supporting more independent settling is something your family wants to work toward.

Four to Six Months: Consolidation and Nap Development

With the four-month transition behind it, many babies begin to consolidate toward more predictable nap and sleep patterns between four and six months. Wake windows extend to approximately 1.5 to 2.5 hours, and most babies are settling into a rough two-to-three nap pattern by around five months. Overnight sleep may lengthen, though night feeds remain nutritionally appropriate for most babies in this age range. A consistent bedtime routine and a predictable nap schedule become genuinely useful tools at this stage — not because they create sleep, but because they work with the circadian rhythm that is now more firmly established. The eight-to-ten month sleep regression is the next significant disruption on the horizon, often associated with the development of separation anxiety and object permanence.

Six to Nine Months: Two Naps and Growing Independence

Most babies have consolidated to two naps by around six to eight months — a morning nap and an afternoon nap, with wake windows of approximately 2.5 to 3 hours. Total daytime sleep is typically around two to three hours, with the majority of overnight sleep consolidated into a longer stretch. Some babies are capable of self-settling independently by this age; others continue to need parental support and will do so for many more months. Both are within the range of normal development. Solid food introduction from around six months begins to reduce reliance on night feeding for nutrition, though habit-based night waking often continues independently of hunger.

Nine to Twelve Months: Approaching the Nap Transition

The period from nine to twelve months often brings another disruption — the twelve-month regression, associated with a developmental leap in cognition, mobility, and social understanding. Many babies in this age range begin resisting one or both naps, or fighting bedtime, without yet being ready for the two-to-one nap transition. This is a confusing period for parents because the behaviour looks like readiness for one nap, but moving too early typically results in an overtired, unhappy baby. Holding two naps and managing the resistance with patience tends to produce better outcomes than rushing the transition. Most babies make the transition from two naps to one somewhere between twelve and eighteen months — when genuine readiness signs are consistently present.

“”Sleep at each age has its own logic. When parents understand what is developmentally expected at their baby’s stage — rather than measuring against a single idealised standard — they find both more patience for the process and more confidence in their responses.””

— Dr. Wendy Hall, professor of nursing at the University of British Columbia and researcher in infant sleep and parent wellbeing. Professor Hall’s longitudinal research on sleep development across the first year consistently emphasises the importance of age-appropriate expectations and the significant variation in individual developmental timelines.

For a broader overview of baby sleep foundations — including safe sleep, wake windows, and building a bedtime routine — visit our full Baby Sleep Beginner Guide in the Baby Care section.

Frequently Asked Questions

My four-month-old was sleeping well and has suddenly started waking constantly — what happened?

This is the four-month sleep regression, and it is one of the most commonly reported sleep changes in the first year. Around this age, a baby’s sleep architecture permanently matures to include full light-sleep arousals between cycles — meaning they now surface between cycles in a way that often requires settling support to return to sleep. It is not caused by anything you did or did not do, and it is not reversible. What it does mean is that settling strategies may need to be reconsidered, and gradually supporting independent settling — if that is a route your family wants to take — is most effective from this age onwards.

How many naps should my six-month-old be having?

Most six-month-olds are taking two to three naps per day, with the majority consolidating to two naps by around six to eight months. The total amount of daytime sleep is typically around two to three hours, though individual babies vary. The timing of naps matters as much as the number — the last nap of the day should typically finish two to two and a half hours before bedtime to preserve sleep pressure for the overnight period. If your six-month-old seems to be resisting a third nap but is not ready for a two-nap schedule, an earlier bedtime can bridge the gap.

What time should my baby’s bedtime be?

Bedtime for babies in the second half of the first year is typically between 6pm and 8pm, with many sleep specialists suggesting 7pm to 7:30pm as a workable target for most babies. An earlier bedtime is often more effective than a later one for avoiding overtiredness — counterintuitively, overtired babies frequently take longer to settle and wake earlier, not later. The most accurate guide to bedtime timing is the last nap finish time combined with the baby’s wake window — bedtime should fall at the end of an appropriate wake window from the last nap, not at a fixed clock time regardless of when the last nap ended.

Is it normal for my baby to wake up at 5am even with a good sleep routine?

Early waking — before around 6am — is one of the most frustrating and persistent baby sleep challenges, and one of the least responsive to routine changes alone. Common causes include: the last nap finishing too early (leaving a long wake window that brings the overnight sleep period to a natural end by 5am), a bedtime that is too late (paradoxically, early waking often improves with an earlier bedtime), too much light entering the sleep environment in the early morning (blackout blinds make a significant difference), or simply a biological early riser whose natural rhythm tends toward early waking. Most early waking requires systematic investigation of these factors rather than a single fix.

Key Takeaways

• Newborn sleep (0–6 weeks) has no reliable pattern — total sleep is 14–17 hours distributed across 24 hours, with no day-night distinction until the circadian rhythm develops around 6–8 weeks.
• The four-month sleep change is the most significant of the first year — sleep architecture permanently matures, and previously effective settling strategies may need to be revisited.
• Most babies consolidate to two naps by 6–8 months, with wake windows of approximately 2.5–3 hours at this stage.
• The two-to-one nap transition typically happens between 14 and 18 months — readiness signs matter more than age.
• Applying age-appropriate sleep expectations removes the distress of measuring your baby against the wrong developmental stage.
• Individual variation within each age stage is wide — a baby who is developing well but sleeping differently from the average is almost always simply an individual baby, not a sleep problem.

Baby sleep across the first year is genuinely complex — but it follows a developmental logic that becomes much clearer when you understand the sequence. Every challenging stage has a reason behind it, a typical duration, and a natural next step that follows from it. Knowing where you are in that sequence, and what comes next, makes the difficult nights more navigable — not because the nights get easier to live through, but because they make sense. And things that make sense are far easier to ride out than things that feel random and endless.