Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Next nap/sleep time
9:30 AM
Suggested bedtime
2:30 PM
Current wake window (minutes)
150
Typical naps per day at this age
2
Target night sleep (hours)
11.0
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter baby's age (months).
- 2Enter hour woke up (24h, e.g. 7 = 7am).
- 3Enter minute woke up.
- 4Read your next nap/sleep time on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
A 'wake window' is the amount of time a baby can comfortably stay awake between sleep periods before overtiredness makes falling asleep harder, and it changes fast in the first two years — a newborn maxes out around 45-60 minutes awake, while a 2-year-old can go 5-6 hours. This calculator takes your baby's age and last wake-up time, applies an age-appropriate wake window range, and projects the next nap time and likely bedtime, giving you a same-day schedule instead of a generic age-based chart you have to do math on yourself.
Worked example
Using the values the calculator loads with:
Inputs
- Baby's age: 6 months
- Hour woke up (24h, e.g. 7 = 7am): 7
- Minute woke up: 0
Results
- Next nap/sleep time: 9:30 AM
- Suggested bedtime: 2:30 PM
- Current wake window (minutes): 150
- Typical naps per day at this age: 2
- Target night sleep (hours): 11
What each field means
Inputs
- Baby's age (months)
- The baby's age used in the calculation, measured in months. Starts at 6 months so you have a working example on load. Accepted range: 0–36 months.
- Hour woke up (24h, e.g. 7 = 7am)
- The hour woke up (24h, e.g. 7 = 7am) used in the calculation. Starts at 7 so you have a working example on load. Accepted range: 0–23.
- Minute woke up
- The minute woke up used in the calculation. Starts at 0 so you have a working example on load. Accepted range: 0–59.
Results
- Next nap/sleep time
- Returned as a plain value and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Suggested bedtime
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Current wake window (minutes)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Typical naps per day at this age
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Target night sleep (hours)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What happens if I miss the wake window and let my baby stay up longer?
Past the ideal window, babies release cortisol and adrenaline to power through tiredness, which often makes falling asleep harder and naps shorter, not easier — the common 'overtired and wired' pattern. Watching for early sleepy cues (rubbing eyes, staring off, slowing down) and acting a few minutes before the window closes usually beats waiting for obvious meltdown signs.
Why do wake windows vary so much even at the same age?
These are ranges, not fixed rules — temperament, how well the last sleep period went, growth spurts, and illness all shift things day to day. Use this as a starting estimate and adjust by 15-30 minutes based on how your specific baby responds over a few days.
When should naps transition from multiple to fewer per day?
Common transition points are 4-to-3 naps around 6 months, 3-to-2 around 6-9 months, 2-to-1 around 15-18 months, and dropping the last nap between 3-5 years. Signs of readiness include consistently fighting a nap or it pushing bedtime too late, not just hitting an age milestone.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Baby Sleep Schedule & Wake Window Planner. Retrieved from https://www.revenuelab.fyi/toolbox/wake-window-planner
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/wake-window-planner" target="_blank" rel="noopener">Baby Sleep Schedule & Wake Window Planner — RevenueLab</a> (2026).</p>
Source: [Baby Sleep Schedule & Wake Window Planner — RevenueLab](https://www.revenuelab.fyi/toolbox/wake-window-planner) (2026).