A 4-month-old needs 12 to 16 hours of total sleep per day, split between nighttime sleep and three to four daytime naps. But “how” matters just as much as “how much.” Four months is a turning point: your baby’s sleep biology is changing, safe sleep rules shift as new physical skills emerge, and the way you set up their sleep environment and routine starts to have a bigger impact than it did in the newborn stage.
Safe Sleep Position and Surface
Every sleep, whether a nap or nighttime, should happen on the back on a firm, flat surface. The mattress should not indent when your baby lies on it, and any incline greater than 10 degrees is unsafe. The crib mattress needs to be designed for your specific crib, fitting tightly with no gaps, covered by a fitted sheet and nothing else.
That means no pillows, blankets, quilts, comforters, stuffed animals, bumper pads, or mattress toppers in the crib. Weighted blankets, weighted swaddles, and weighted sleepers are also off-limits. The sleep space should be completely bare except for the fitted sheet and your baby.
When to Stop Swaddling
Many babies start showing signs of rolling around 4 months, and this changes one important rule: you need to stop swaddling as soon as your baby shows any signs of trying to roll over. A swaddled baby who rolls onto their stomach can’t use their arms to reposition, which increases the risk of suffocation. Even before rolling, swaddling reduces a baby’s ability to wake themselves up, which is one reason it helps them sleep longer but also one reason it carries risk.
A wearable sleep sack with fitted neck openings and full arm and leg movement is the safe alternative. Sleep sacks keep your baby warm without restricting their ability to move or push up if they roll.
Room Temperature and Clothing
Keep the room between 68°F and 72°F. A good rule of thumb: dress your baby in one more layer than you’d wear comfortably at the same temperature. Light layers are easier to adjust than heavy ones, and a sleep sack counts as a layer. If your baby’s chest or back feels hot or sweaty to the touch, they’re overdressed.
What Changes at 4 Months
In the first few months, babies spend most of their sleep in deep stages. Around 4 months, the brain reorganizes sleep into cycles of light and deep stages, more like adult sleep. This is a permanent, healthy change, but it means your baby now passes through light sleep phases where they’re more likely to wake up briefly.
This transition is what people call the “4-month sleep regression.” It’s not really a regression. It’s a one-time shift in sleep architecture. Your baby’s brain and nervous system are developing rapidly, forming and linking new connections, and that process can make sleep temporarily unstable. Babies who previously slept long stretches may suddenly wake more often, have shorter naps, or resist falling asleep. This phase typically lasts a few weeks.
Wake Windows and Nap Schedule
Most 4-month-olds can handle 1.5 to 2.5 hours of awake time before they need to sleep again. That awake window includes feeding, playing, and whatever tummy time or interaction you fit in. Once you hit that window, your baby is ready for a nap. Three to four naps per day is typical at this age, with nap lengths varying quite a bit from baby to baby.
Watch for tired signs rather than relying on the clock alone. At this age, tiredness shows up as fussiness, clinginess, crying, increased activity (counterintuitively), losing interest in toys, or generally seeming “off.” If your baby gets past those cues and becomes overtired, settling them to sleep gets significantly harder. Catching that window early makes the whole process smoother.
Nighttime Feedings
By 4 months, many babies can go five or more hours between nighttime feedings. One to two overnight feeds is still normal and expected. If your baby is waking to feed more than twice per night at this age, it may be worth looking at whether some of those wakings are habit-based rather than hunger-based, especially if they’re only taking small amounts before falling back asleep.
Breastfed babies tend to wake more frequently than formula-fed babies because breast milk digests faster. Neither pattern is a problem. The goal isn’t to eliminate night feeds at 4 months but to recognize that your baby’s stomach capacity has grown enough that every waking doesn’t necessarily mean hunger.
Building a Bedtime Routine
Four months is a good time to establish a consistent pre-sleep routine if you haven’t already. It doesn’t need to be elaborate. A short, predictable sequence (feeding, a quick change, dimming the lights, a few minutes of rocking or singing) signals to your baby that sleep is coming. Consistency matters more than the specific activities. Doing the same thing in the same order before every sleep helps your baby’s brain start associating those cues with falling asleep.
Putting your baby down drowsy but still awake, even occasionally, helps them start learning to fall asleep without being held or fed all the way to sleep. This isn’t a strict rule at 4 months. It’s a direction to move toward gradually.
Sleep Training at 4 Months
Four months (and at least 14 pounds) is generally considered the earliest appropriate age to start formal sleep training, if you choose to. There are several approaches with different levels of parent involvement.
- Graduated extinction (Ferber method): You check on your baby at progressively longer intervals, offering brief comfort without picking them up. This typically takes 7 to 10 days.
- Chair method: You sit in a chair next to the crib until your baby falls asleep, then move the chair farther away each night. This is gentler but can take up to four weeks.
- Full extinction (cry-it-out): You put your baby down and don’t intervene until morning or the next scheduled feeding. This is the fastest but hardest for most parents.
Sleep training is not required. Plenty of families don’t do it at all, and plenty of babies learn to sleep well without any formal method. If your baby’s sleep patterns are working for your family, there’s no reason to change anything. If nighttime wakings are unsustainable and your baby is at least 4 months old and gaining weight well, it’s a reasonable option.
What a Typical Day Looks Like
A 4-month-old’s day generally follows a pattern of wake, eat, play, sleep, repeating in roughly 2-hour cycles during the day. Bedtime tends to fall somewhere between 6:30 and 8:00 p.m., with a longer stretch of nighttime sleep (often the longest stretch happening in the first half of the night), one to two feeds, and a morning wake-up between 6:00 and 7:30 a.m. Naps might be 30 minutes to 2 hours each, and short naps are completely normal at this age since your baby is still learning to connect sleep cycles during the day.
The most useful thing you can do at 4 months is pay attention to your individual baby’s patterns rather than forcing a rigid schedule. Track when they seem tired, how long they can stay awake comfortably, and what helps them settle. Those observations will tell you more than any generic schedule chart.