Wake Window Calculator

How it is calculated

The tool looks up the age in months in a fixed table of age bands, with no formula or interpolation. The bands, by age a, are: under 2 months 45–60 min; 2 to under 3 months 60–90 min; 3 to under 4 months 75–105 min; 4 to under 6 months 90–120 min; 6 to under 9 months 120–180 min; 9 to under 13 months 150–240 min; 13 to under 19 months 240–330 min; 19 to 36 months 300–360 min. Alongside the wake window in minutes, it shows the usual number of naps per day and a range for total sleep in 24 hours, naps included: 14–17 hours under 4 months (National Sleep Foundation, 0–3 months), 12–16 hours from 4 to under 13 months and 11–14 hours from 13 months to under 36 months (American Academy of Sleep Medicine), and 10–13 hours at 36 months. Decimals are accepted, so 7.5 works, and 0 is valid for a newborn. Ages below 0 or above 36 months give no result. The wake windows and nap counts are typical figures from parenting guidance with no clinical source, not a prescription for an individual child; only the total-sleep ranges come from the sleep-medicine recommendations.

Common mistakes

• Reading the range as an exact schedule. A window of 120–180 min means the span within which most babies of this age settle, so watch for tired signs inside it.
• Entering the age in weeks or years. The field is in months, so a 1-year-old is 12 and a 6-week-old is about 1.5.
• Using the corrected age of a baby born early without thinking about which age you meant to enter. The tool applies the band to whatever number you enter and cannot adjust for early birth.
• Expecting a smooth change from one day to the next. The bands jump at fixed ages, so 12.9 months gives 150–240 min and 13 months gives 240–330 min.
• Entering an age above 36 months for an older child and expecting an extrapolated value. The table stops at 36 months and gives no result beyond it.