Most babies can safely sleep through the night (6 to 8 hours without feeding) starting around 3 to 4 months of age, though some don’t reach this milestone until closer to 1 year. In the first weeks of life, however, newborns need to eat every 2 to 3 hours and should not be left to sleep long stretches. The shift from “wake them to feed” to “let them sleep” depends on your baby’s age, weight gain, and overall health.
Why Newborns Can’t Sleep Through the Night
Newborns have tiny stomachs and fast metabolisms. They physically cannot go more than about 4 to 5 hours without eating, and most need to feed every 2 to 3 hours. In the first days of life, formula-fed babies typically eat 1 to 2 ounces per feeding across 8 to 12 sessions in a 24-hour period. Breastfed babies feed on a similar schedule while milk supply establishes.
Beyond hunger, newborns lack a functioning internal clock. Their sleep is scattered across the full 24-hour day in short bursts, rarely exceeding 4 hours at a stretch. A true day-night pattern doesn’t develop until about 12 to 16 weeks, when the circadian rhythm matures enough to consolidate longer sleep into nighttime hours. Before that point, expecting a baby to sleep a long stretch at night isn’t just optimistic, it’s biologically premature.
There’s also a medical reason to keep feedings regular. Newborns are vulnerable to low blood sugar, which in severe or prolonged cases can affect brain development. Frequent feedings keep blood sugar stable during those critical early weeks. Babies with jaundice, prematurity, or low birth weight are at even higher risk and may need feedings on a stricter schedule set by their pediatrician.
The 3-to-4-Month Turning Point
Around 3 months, several things converge. The circadian rhythm begins functioning, so babies naturally start sleeping longer at night and less during the day. Their stomachs are larger, meaning they can take in more calories per feeding and go longer between meals. Formula-fed babies at this age typically eat every 3 to 4 hours rather than every 2 to 3.
This is generally when pediatricians stop recommending that you wake a healthy, normally growing baby to feed at night. If your baby has regained their birth weight, is gaining steadily, and is eating well during the day, a 6-to-8-hour nighttime stretch is usually fine. Some babies start doing this on their own. Others continue waking, which is also normal.
The key word is “healthy.” Babies who were premature, are underweight, or have medical conditions may need nighttime calories longer. If your pediatrician has asked you to maintain a feeding schedule, follow that guidance even if your baby seems content sleeping.
Signs Your Baby Is Ready
Rather than picking a date on the calendar, watch for these signals that your baby can go all night without eating:
- Steady weight gain. Your baby is consistently following their growth curve at checkups.
- Enough daytime calories. They’re eating full, frequent meals during waking hours and don’t seem to be making up for missed daytime nutrition at night.
- Longer natural stretches. They’re already sleeping 4 to 5 hours at a time without you intervening.
- Waking without hunger cues. When they do wake at night, they may fuss but settle without actually eating much, suggesting they want comfort rather than calories.
By 6 months, most babies are getting enough food during the day to support their growth and development without nighttime feeds. Formula-fed babies over 6 months who wake at night are rarely waking from hunger. Breastfed babies may still wake more often, but this doesn’t necessarily mean they need the calories (more on that below).
Breastfed vs. Formula-Fed Babies
There’s a common assumption that formula-fed babies sleep longer because formula is harder to digest and keeps them fuller. The reality is more nuanced. Research published in the American Journal of Clinical Nutrition found that fully breastfed infants actually had longer total nighttime sleep durations than formula-fed infants at 6, 9, 12, and 24 months. However, breastfed babies woke up more often between 6 and 12 months.
So breastfed babies sleep longer overall at night but in more fragmented chunks. Those extra wake-ups are often about comfort and the nursing association rather than genuine hunger. This is worth knowing because it means a breastfed baby waking at 8 months isn’t necessarily telling you they need more food. They may just need help learning to fall back asleep without nursing.
For breastfeeding parents, there’s an additional consideration: very long gaps between feeds in the early months can affect milk supply. If you’re exclusively breastfeeding and your baby starts sleeping 6-plus hours before 3 months, you may need to pump once overnight to maintain production, even if the baby doesn’t need to eat.
A Rough Timeline
Every baby is different, but here’s a general framework for what to expect:
- 0 to 2 weeks: Feed every 2 to 3 hours, day and night. Wake your baby if needed. This is non-negotiable for healthy blood sugar and weight recovery.
- 2 to 8 weeks: Most babies still need at least one or two nighttime feeds. The longest sleep stretch might reach 4 to 5 hours once per day. Many pediatricians suggest waking your baby at 10 or 11 PM for a late feed to help them make it through the night.
- 3 to 4 months: The circadian rhythm kicks in. Healthy babies with good weight gain can often be allowed to sleep as long as they want at night. Many will sleep 6 to 8 hours.
- 6 months and beyond: Most babies are physically capable of going all night without eating. Night waking at this point is typically habitual or comfort-seeking rather than hunger-driven.
What “Sleeping Through the Night” Actually Means
Pediatricians define sleeping through the night as a 6-to-8-hour stretch, not the 10 or 11 hours an adult might hope for. A baby who sleeps from 7 PM to 1 AM has technically slept through the night by medical standards, even if it doesn’t feel that way to you. Truly long stretches of 10-plus hours tend to come later, often between 6 and 12 months, and even then, brief wake-ups are biologically normal. Adults wake briefly between sleep cycles too; we just don’t remember it.
If your baby was sleeping through the night and suddenly starts waking again, that’s also common. Growth spurts, teething, illness, and developmental leaps (like learning to crawl or stand) frequently disrupt sleep temporarily. A regression at 4 months is so predictable it has its own name. These phases pass, and they don’t mean your baby has lost the ability to sleep long stretches.