Baby wake window calculator
Enter your baby's age in months and when they last woke up to see the usual awake window for that age, the time range in which the next sleep might start and the typical number of naps. The numbers are approximate guidance, not rules.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Type your baby’s age in whole months (0 to 24).
- Set the time they woke up.
- Read the typical awake window, the time range in which the next sleep might start, and the usual number of naps. The table shows all ages with yours highlighted.
How it works
The next sleep window is the wake-up time plus the shortest and the longest awake time for the age band. Times past midnight wrap around to the early hours.
Worked example
A 6-month-old (120 to 180 minutes awake) who woke at 07:00: the next sleep window is 09:00 to 10:00, and about 3 naps a day is typical.
Notes
Use the window as a guide and watch for tired cues such as yawning, rubbing eyes or fussing. Windows shift during growth spurts, illness and nap transitions. This tool is general information only and not medical advice.
Frequently asked questions
What is a wake window?
The stretch of time a baby is comfortably awake between one sleep and the next. Younger babies tire quickly and have short windows; the windows lengthen as they grow.
How is the next sleep time worked out?
The tool adds the shortest and longest awake time for the age to the wake-up time you enter. For a 4-month-old (90 to 150 minutes) waking at 07:00 that gives 08:30 to 09:30.
Where do the ranges come from?
They are approximate figures commonly published by paediatric sleep consultants and parenting resources. They overlap and differ between sources, so treat them as a starting point rather than a standard.
My baby does not follow the table. Is something wrong?
Babies vary a lot, and tiredness cues matter more than the clock. This tool does not diagnose anything; if you have concerns about your baby's sleep, talk to a doctor or health visitor.
How much sleep does a baby need in total?
The American Academy of Sleep Medicine's 2016 consensus statement recommends 12 to 16 hours per 24 hours, including naps, for babies aged 4 to 12 months, and 11 to 14 hours for ages 1 to 2 years. Newborns sleep in shorter, irregular stretches.