Baby wake windows calculator: how long between sleeps

Wake windows by age: the full table

These are the six age bands Cleveland Clinic publishes, in their numbers, and the same ranges the LEELALU app tracker uses to guess the next sleepy window. This page and the app never disagree. They are gentle guesses, not rules.

Two honest gaps. The published table has no row between 4 and 5 months, so a baby that age keeps the 3 to 4 month range and the calculator says so. And it stops at 12 months, so past the first birthday we have no range to give you and will not invent one.

How to use these ranges

Treat the range as a frame, and your baby's cues as the picture. Toward the end of a wake window, watch for the early sleepy signs: a glazed stare, slower movements, turning away from faces, a first yawn. Starting the wind-down on the early side of the range is usually easier than catching up with an overtired baby.

For context on why the windows start so short: newborns sleep about 16 to 17 hours across a full day, often in stretches of only 1 to 2 hours, so short awake stretches are simply the arithmetic of that much sleep (AAP HealthyChildren, sourced below).

• Shorter than the range and happy? Some babies simply need less. That can be normal.
• Fighting sleep at the end of the range? Try moving the wind-down 10 to 15 minutes earlier for a few days.
• Every baby varies, and the same baby varies week to week. Growth spurts, illness, and new skills all shuffle the schedule for a while.

Born early? Count from the due date

For babies born before 37 weeks, sleep development tends to follow the corrected age (age counted from the due date) rather than the birth date. That is why the calculator has the optional "weeks early" field: it shifts the table to your baby's corrected age.