Babies start sleeping noticeably less around 4 months old, when total sleep drops from 16 to 17 hours a day down to 12 to 16 hours. From there, sleep continues to gradually decrease through the first year and into toddlerhood, reaching 11 to 14 hours (including naps) by age one to two. The shift doesn’t happen overnight. It unfolds in stages tied to brain development, physical milestones, and changes in how your baby’s internal clock works.
How Sleep Changes in the First Year
Newborns are the heaviest sleepers you’ll ever meet. They average 16 to 17 hours of sleep per day, but it comes in short bursts of just one to two hours at a time, scattered across day and night with no real pattern. That’s because newborns don’t yet have a functioning internal clock. The human body doesn’t begin producing melatonin, the hormone that signals nighttime, until several weeks after birth. Around 6 to 8 weeks, a rough day-night rhythm starts to emerge, and by about two months, many babies begin consolidating more of their sleep into nighttime hours.
Between 4 and 12 months, total sleep drops to roughly 12 to 16 hours per day. That’s still a lot, but the structure changes dramatically. Instead of sleeping in random chunks, babies start taking more predictable naps during the day and sleeping longer stretches at night. By 12 months, 70% to 80% of infants are sleeping primarily at night.
Toddlers between 12 and 24 months need about 11 to 14 hours total, including naps. So from birth to the second birthday, your baby loses roughly 4 to 5 hours of daily sleep, most of it shed from daytime naps.
Why Newborns Sleep So Much
Half of a newborn’s sleep is spent in REM, the phase associated with brain development. That’s a far higher proportion than older children or adults experience. Premature infants spend even more time in REM, up to 80% of their sleep. This isn’t laziness or a quirk. The newborn brain is building neural connections at an extraordinary pace, and REM sleep appears to be when much of that wiring happens. As the brain matures through the first year, the proportion of REM sleep gradually decreases and deeper, quieter sleep phases take up more of the night.
When Naps Start Dropping Off
The number of naps your baby takes is one of the clearest markers of the transition away from “sleeping all the time.” Most babies follow a predictable pattern:
- 4 to 6 months: Drop from 4 or 5 short naps down to 3 more consistent ones.
- 8 to 9 months: Drop from 3 naps to 2 (typically a morning and an afternoon nap).
- 13 to 18 months: Drop from 2 naps to 1, usually around lunchtime.
Each of these transitions means less total daytime sleep. The shift from two naps to one is often the most noticeable for parents because it’s when your child starts having long, fully awake stretches during the day for the first time. Some toddlers around age two resist their remaining nap entirely, a phase sometimes called a “nap strike,” though most still benefit from that midday rest.
Sleep Regressions Can Make It Feel Unpredictable
Just when you think your baby is settling into a rhythm, a sleep regression can scramble everything. These are temporary periods, usually lasting a few days to a few weeks, when a baby who was sleeping well suddenly starts waking more at night or fighting naps. They tend to cluster around developmental milestones.
Between six and ten months, many babies learn to crawl, roll, and scoot. The physical exertion and mental focus these skills require can lead to overstimulation, making it harder to settle down. Some babies even practice crawling in their crib instead of sleeping. A similar disruption often happens around 12 months, when walking enters the picture. Separation anxiety, which builds as babies develop stronger social awareness, and teething pain can layer on top of these physical milestones. The result is a stretch of rough nights that feels like a step backward but is actually a sign of healthy development.
Solid Foods and Nighttime Sleep
One factor that can nudge sleep patterns forward is the introduction of solid foods. A randomized clinical trial of over 1,300 infants published in JAMA Pediatrics found that babies who started solids before six months slept longer at night, woke less frequently, and had fewer serious sleep problems compared to babies who were exclusively breastfed until six months. The improvements were modest but consistent. This doesn’t mean you should rush to start solids purely for sleep reasons, but it does suggest that the shift from an all-liquid diet to solids plays a role in how sleep consolidates.
What the Shift Actually Looks Like
The transition from “sleeping all the time” to a more adult-like pattern isn’t a single moment. It’s a gradual process with a few key inflection points. The first big shift happens around 4 months, when total sleep hours drop and nighttime stretches get longer. The second comes between 8 and 12 months, as naps decrease and the majority of sleep moves to nighttime. By 12 to 18 months, most toddlers are down to one nap and sleeping 10 to 12 hours at night, which looks much more like a recognizable schedule.
Every baby’s timeline varies. Some consolidate sleep quickly and sleep long stretches at night by 4 months. Others take well past their first birthday to get there. Both are normal. The overall trend, though, is consistent: the heavy, round-the-clock sleeping of the newborn period fades steadily through the first year, with the most dramatic drop happening in the first four to six months.