4 month old sleep schedule

Four months is where sleep stops being newborn sleep. It is also where most parents suddenly find themselves up four times a night.

Most 4 month olds land on 12 to 16 hours of sleep across 24 hours, 3 to 4 naps, and wake windows of roughly 90 to 120 minutes. Shortest window first thing in the morning, longest before bed.

A day that actually works

The times are a sketch. The wake windows are the part worth holding onto, because they are what stops a baby arriving at a nap already overtired.

The thing to get right at 4 months

This is the age of the regression, and it is not a regression at all: sleep cycles mature into an adult-like structure and stay that way. Nothing goes back.

Four month olds become intensely distractible. A baby who used to feed and settle anywhere now stops to look at everything, which shortens naps and lengthens feeds. Watching the clock beats waiting for cues at every age under one, and a baby who is past the window fights the nap you were trying to give them.

Night sleep at 4 months

Night sleep often gets dramatically worse this month even though nothing is wrong. Babies who slept a six hour stretch at 12 weeks commonly wake every two hours at 17 weeks, then settle again over three to six weeks.

Two babies, two regressions

One twin usually hits it before the other, so you get two rough patches back to back rather than one. Holding both morning wake-ups steady through it is the only thing that reliably shortens the disruption.

Everything above applies to each baby on their own, which is the problem: two babies on separate schedules means nobody is ever asleep at the same time. One decision does most of the work, and it is the morning. Wake both babies within about half an hour of each other and the rest of the day follows. During the day the rule flips, though: let a nap finish rather than rousing the second baby, then shorten the next wake window for whoever is running ahead.

If your twins were born early, use corrected age for all of this. A baby born eight weeks premature follows a schedule about eight weeks behind their calendar age, and the smaller twin often needs slightly shorter windows than their sibling.

Where it usually goes wrong

If you are here because sleep fell apart overnight, you are almost certainly in the regression rather than doing something wrong. The fix is not a new routine; it is holding the existing one steady while the change finishes.

What changes at 5 months

Rolling often starts now, which means swaddles come off. Drop the swaddle before the regression if you can, not during it.

Where the app fits

What helps at this age is a record, not more advice. Multibaby lets you log both babies through a rough fortnight, so you can tell the difference between a regression that is ending and one that has become a habit. The wake window calculator will do the arithmetic for a single nap if you just need the next one.