Baby Sleep Schedule Calculator by Age
Tell it when your baby woke up, their age, and how many naps you are planning. It builds suggested nap windows and a bedtime range from there, and flags the days that are heading toward overtired. A gentle map for the day, not a rulebook.
How to read your schedule
Each nap is shown as a window, for example 9:00 to 9:30, rather than a single minute. The earlier number is when to start watching for tired cues; the later number is when to have your baby settled by. Aim to put them down somewhere inside that window, closer to the early edge on days they seem wiped, closer to the late edge on bright, easy days.
The bedtime range works the same way. It floats with how the naps actually went: a short-nap day pulls bedtime earlier, a long restorative nap pushes it a little later. Treat the whole thing as a starting shape and adjust by what your baby shows you, not by what the clock says.
Where these times come from
A sleep schedule is really just wake windows laid end to end. A wake window is the time your baby can stay happily awake between sleeps. It grows with age: around an hour and a half at 4 months, two to two and a half hours at 6 months, closer to three hours at 9 to 12 months, and five to six hours by 18 months, when a single midday nap carries the day.
Two patterns hold across almost every age. The first wake window of the morning is the shortest, because sleep pressure is lowest right after a full night. The last window before bed is the longest, which is why a baby who napped well can still happily power through a long late afternoon. This calculator builds your day around both of those rules, then adds a buffer to the bedtime window so an off-day nap does not blow the evening apart.
The ranges reflect typical figures cited by pediatric bodies such as the American Academy of Pediatrics and the National Sleep Foundation, alongside consensus from pediatric sleep research. They describe what is common, not what is required. A baby who sits a little outside them and is thriving is simply their own kind of normal.
groupsWhat an overtired evening actually looks like
The schedule keeps the day on track. Here is how parents usually realise it slipped:
- Second wind at 6pm, suddenly wired instead of winding down
- Bedtime takes an hour when it normally takes ten minutes
- Split nights, awake and cheerful at 2am for no clear reason
- Early-morning wake before 6am, more tired equals earlier rising
- Catnaps only, every nap collapses to 30 minutes
- Crying at the cot the moment they are laid down
If two or three of these stack up, the fix is usually an earlier bedtime tonight, not a later one. A baby who is already overtired needs to bank sleep, not stay up to "earn" it. Pair this with the wake windows calculator if you want to fine-tune a single gap.
Typical schedule shapes by age
| Age | Naps | Wake window | Bedtime (approx.) |
|---|---|---|---|
| 4 mo | 3 – 4 | 1.5 – 2 h | 6:30 – 7:00 pm |
| 6 mo | 3 | 2 – 2.5 h | 6:00 – 6:45 pm |
| 9 mo | 2 | 2.75 – 3.25 h | 6:30 – 7:15 pm |
| 12 mo | 2 | 3 – 3.75 h | 7:30 – 8:15 pm |
| 15 mo | 2 | 3 – 3.75 h | 7:30 – 8:15 pm |
| 18 mo | 1 | 5 – 5.5 h | 7:30 – 8:00 pm |
help_outlineFAQ
How does this sleep schedule calculator work?
It starts from the time your baby woke up this morning and chains together the typical wake windows for their age, shortest in the morning, longest before bed.
Add the number of naps and it returns a suggested window for each nap plus a bedtime range, so you can plan the day instead of watching the clock all afternoon.
Why is the result a window instead of an exact time?
Babies are not stopwatches. A wake window of 2 to 2.5 hours is normal, and tired cues land anywhere inside it from one day to the next.
A window tells you when to start watching for sleepy signs and when to have your baby down by, which is far more useful than a single minute.
My baby's bedtime comes out very late. What should I change?
A late bedtime usually means the wake-up was late, a nap ran too long, or there were too few naps to carry the day.
Cap the last nap so it ends a few hours before bed, or add a short nap when one runs short. An earlier morning start often pulls bedtime earlier too.
How many naps should my baby have?
Roughly 3 to 4 naps around 4 months, 3 around 6 months, 2 from about 9 to 15 months, and 1 from around 15 to 18 months until age 3 to 4.
The calculator pre-selects a typical count for the age you pick, and you can change it to match the day you are actually having.
Is an overtired baby just a baby who needs less sleep?
No. Overtiredness comes from staying awake past the point where settling is easy. It shows up as crying, fighting sleep, short naps, and more night waking.
If your baby resists sleep yet wakes unrefreshed, the day is usually too stretched rather than too full.
Does this replace advice from my pediatrician?
No. These are typical reference ranges to help you plan, not a diagnosis.
If your baby is consistently far outside the ranges, snores or pauses breathing in sleep, is not gaining weight, or you are worried, talk to your pediatrician.
Sources
- American Academy of Pediatrics, Healthy Sleep Habits
- National Sleep Foundation, Sleep duration recommendations
- Paruthi S. et al. (2016). Recommended Amount of Sleep for Pediatric Populations: Consensus Statement. J Clin Sleep Med, 12(6).
- Hirshkowitz M. et al. (2015). National Sleep Foundation's sleep time duration recommendations. Sleep Health, 1(1).
This content is informational and does not replace pediatric care. Talk to your child's doctor for individual guidance.