A healthy 5-week-old who is gaining weight well can typically sleep for a stretch of 4 to 5 hours at a time, usually at night. Over a full 24-hour period, most newborns this age sleep around 16 to 17 hours total, broken into many shorter chunks spread across day and night.
If your baby is sleeping longer than you expected, or shorter, here’s what’s actually going on at this age and what matters for their safety and feeding.
Longest Sleep Stretch at 5 Weeks
By about two weeks of age, most babies can sleep for as long a stretch as their body allows, which at 5 weeks is generally 4 to 5 hours. This is the longest stretch you should expect, and it usually happens at night. During these longer stretches, your baby isn’t necessarily sleeping solidly the entire time. They wake briefly between sleep cycles but are learning to drift back to sleep on their own.
During the day, sleep looks different. Naps at this age tend to last about 3 to 4 hours and are spaced around feedings. After being awake for just 1 to 2 hours, most newborns need to sleep again. That means your baby is probably taking four or more naps a day, with very short awake windows in between.
When to Let Them Sleep vs. Wake for Feeding
The key factor is weight gain. Most newborns lose weight in the first few days after birth and regain it within 1 to 2 weeks. Once your baby has reached their birth weight and is showing a consistent pattern of weight gain, it’s generally fine to let them sleep until they wake up on their own, even if that means a 4- or 5-hour stretch without eating.
Before that milestone, or if your baby was born prematurely, waking them to feed is important. Premature babies may not reliably cry or show hunger cues even when they need to eat. If you’re unsure whether your baby’s weight gain is on track, your pediatrician can confirm at a checkup, and most 5-week-olds have had at least one or two by this point.
Why Sleep Feels So Random Right Now
At 5 weeks, your baby doesn’t yet have an internal clock distinguishing day from night. The hormone that regulates sleep-wake cycles, melatonin, doesn’t become detectable in infants until around 12 weeks. Before that, newborn activity is spread fairly evenly across the 24-hour day, which is why it can feel like your baby has no schedule at all.
There is some good news on the horizon. Between 1 and 2 months, awake time starts to consolidate more during daylight hours, and by 3 months, babies are sleeping noticeably more at night and less during the day. At 5 weeks, you’re right at the beginning of that shift, so you may start to notice slightly longer stretches at night and a touch more alertness during the day.
About half of a newborn’s total sleep is spent in active (REM) sleep, which is why you’ll notice twitching, irregular breathing, eye movements, and little sounds even while your baby is asleep. This is completely normal and not a sign they’re about to wake up.
The 6-Week Growth Spurt
Just as you start to feel like sleep is becoming slightly more predictable, many babies hit a growth spurt around 6 weeks that temporarily disrupts everything. During this phase, your baby’s body is growing rapidly and needs more fuel. You may notice a sudden increase in feeding frequency, including more wake-ups at night specifically to eat, even if your baby had been stretching to longer intervals.
This growth spurt often overlaps with what’s sometimes called the 6-week sleep regression. Your baby may seem more restless, harder to settle, and hungrier than usual. Both of these are temporary. They typically resolve within a week or so, and sleep stretches often improve afterward as your baby’s stomach capacity grows along with the rest of them.
Safe Sleep Setup at This Age
However long your baby sleeps, the basics of safe sleep stay the same. Place your baby on their back every time, on a firm, flat mattress in a crib, bassinet, or portable play yard with only a fitted sheet. No blankets, pillows, stuffed animals, or bumpers in the sleep space.
Your baby should sleep in their own space, not in bed with you or on a couch or armchair. If you’re falling asleep during nighttime feedings, feeding in your bed with all pillows and blankets removed is safer than feeding in a chair or on a couch, where the risk of a baby getting trapped is higher. Car seats, swings, and bouncers are not safe sleep surfaces for unsupervised naps, even if your baby falls asleep in one during the day.
What to Expect Over the Next Few Weeks
Sleep at 5 weeks is still very much in newborn territory, but change comes quickly. Between now and 12 weeks, your baby’s internal clock will start producing melatonin, daytime naps will gradually shorten, and nighttime stretches will lengthen. Many babies are sleeping one stretch of 5 to 6 hours by 2 to 3 months.
For now, the 4- to 5-hour maximum stretch is normal and healthy. If your baby is consistently sleeping much longer than that and is difficult to wake for feedings, or if they seem unusually sleepy and aren’t feeding well, that’s worth bringing up with your pediatrician. But if your 5-week-old is gaining weight, eating well when awake, and sleeping in stretches of a few hours at a time, their sleep is doing exactly what it should.