A wake window is the amount of time your child can comfortably stay awake between sleeps. It starts the moment they wake up and ends when they fall asleep again. Wake windows are short in the newborn months, sometimes only 45 minutes, and stretch as your child grows, reaching 5 to 6 hours by toddlerhood.

Timing sleep to these windows matters because a child put down inside their window falls asleep more easily, while one kept awake past it becomes overtired and fights sleep harder.

The calculator takes your morning wake-up time and builds the day forward using typical wake windows and average nap lengths for your child's age. Each nap starts when the wake window closes, and bedtime lands after the final window of the day. The numbers follow widely used pediatric sleep guidance and describe what most children need at each age.

Shift the rest of the day with it. The schedule assumes typical nap lengths, so a 40-minute nap where 90 was planned means the next wake window starts earlier, and everything after moves up. The easiest fix: come back to this calculator, enter the time your child last woke up as the starting point, and read the next sleep time from there. After a day of short naps, an earlier bedtime helps your child catch up.

Sleep pressure, the biological drive to sleep, builds differently across the day. In the morning your child is rested from the night, so the first window is the shortest. By evening, pressure has been building for hours, and your child can handle the longest stretch before bedtime. This is why the schedule shows slightly longer awake times as the day goes on.

Sleepy cues are your child's signals of being ready for sleep: staring off, slowing down, rubbing eyes, pulling ears, fussing. The best approach uses both: the wake window tells you when to start watching, and the cues tell you the moment has arrived. Cues alone can mislead, because by the time some children show clear signs, they're already overtired. Yawning and fussing late in a window usually mean sleep should happen soon.

Not necessarily. These windows are averages, and healthy children sit on both sides of them. What tells you the timing works: naps come without a long battle, naps last beyond one sleep cycle of 40 to 50 minutes, and your child wakes up content. Consistent fighting at naptime, chronically short naps, or an unhappy waking pattern suggest the windows need adjusting for your child.

Most children move from 3 naps to 2 around 7 to 9 months, from 2 naps to 1 somewhere between 13 and 18 months, and give up the last nap between ages 3 and 5. Transitions rarely happen overnight: expect a few weeks where some days have the old schedule and some the new one. Consistently fighting a nap for two weeks or more is the clearest sign a transition has started.

A calculator can give you a starting point, but it can't see your child. If naps are a daily struggle, the schedule never seems to fit, or you're unsure what your little one needs, I'd love to help. Hit reply to the email where you received this link and tell me what's going on. Helping families sleep is what I do.