A baby sleep calculator turns your baby age and wake-up time into nap times and a bedtime. A 6-month-old who wakes at 7:00 AM typically naps around 9:00 AM, 12:30 PM and 4:30 PM and goes to bed about 7:00 PM, for roughly 15 hours of sleep, within the 12 to 16 hours recommended at that age.
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How To Use The Baby Sleep Calculator
- Enter your baby age in months. If your baby was born early, add how many weeks early; the calculator uses corrected age under 2 years.
- Enter the usual morning wake-up time. The plan is built forward from it.
- Use the plan as a starting point. Watch for tired signs and move times by 15 to 30 minutes to suit your baby.
| Result | What it means |
|---|---|
| Suggested bedtime | When to start sleep for the night |
| Nap times | When each nap usually starts at this age |
| Wake windows | The range of awake time between sleeps |
| Total sleep | Planned sleep in 24 hours against the recommended range |
| Corrected age | The age used for premature babies |
What Is A Wake Window?
A wake window is the time a baby spends awake between one sleep and the next. It starts short, around 45 to 90 minutes for a newborn, and grows to 5 hours or more for a toddler on one nap.
Wake windows are a practical tool used by parents and health visitors rather than a research measure, so tired signs such as eye rubbing, yawning or turning away matter more than the clock.
For full tables of naps, wake windows and sample days at every age, see our baby sleep schedule by age.
How Does The Baby Sleep Calculator Work?
It finds the age band, adds the first wake window to the wake-up time to place the first nap, adds the nap length, and repeats until bedtime.
Nap start = Previous wake + Wake window; Bedtime = Last nap end + Final wake window; Corrected age = Age - Weeks early / 4.3| Age (corrected) | Naps | Wake windows | Total sleep recommended |
|---|---|---|---|
| 0 to 3 months | On demand | 45 to 90 min | 14 to 17 h |
| 4 to 6 months | 3 | 2 to 2 h 30 min | 12 to 16 h |
| 7 to 9 months | 2 | 2 h 30 min to 3 h 30 min | 12 to 16 h |
| 10 to 14 months | 2 | 3 to 3 h 30 min | 12 to 16 h, then 11 to 14 h from 12 months |
| 15 to 35 months | 1 | 5 h | 11 to 14 h |
The total-sleep ranges come from the National Sleep Foundation and the American Academy of Sleep Medicine. The nap counts and wake windows are typical guidance.
Worked Example: A 9-Month-Old Born 8 Weeks Early
| Step | Value |
|---|---|
| Corrected age | 9 months – 8 weeks = about 7 months |
| Wake-up | 6:30 AM |
| Nap 1 | 9:00 to 10:30 AM |
| Nap 2 | 1:30 to 3:00 PM |
| Bedtime | 6:30 PM |
| Total sleep | 15 h (12 to 16 h recommended) |
Using the actual age of 9 months would push the windows longer than this baby may manage. Corrected age keeps the plan in line with development.
Factors That Change Your Baby Sleep Schedule
Feeding
Young babies need night feeds, and feeding times shape the day. The schedule should fit around feeds, not the other way round.
Development
Rolling, crawling, standing and talking can all disturb sleep for a while.
Illness, Teething And Travel
Expect a few off days; return to the usual times once things settle.
The Sleep Space
A dark, quiet room at a safe temperature helps; check the range with the sleep temperature calculator.
Two Naps vs One Nap: When To Switch?
| Two naps | One nap | |
|---|---|---|
| Typical age | About 7 to 14 months | About 15 months onward |
| Signs it is time to change | Second nap pushes bedtime late | Refuses the morning nap or fights the second one |
| Wake windows | 3 to 3.5 hours | About 5 hours |
Transitions rarely happen overnight. For a week or two, alternate one-nap and two-nap days and bring bedtime earlier on one-nap days.
Who Should Use A Baby Sleep Calculator?
- New parents wanting a rough shape for the day after the newborn months.
- Parents of premature babies, who need plans based on corrected age.
- Carers and nurseries keeping a baby routine consistent.
- Families planning the whole household, who can check everyone else with the sleep calculator by age.
Common Mistakes With Baby Sleep Schedules
Following The Clock Over The Baby
Tired signs come first; the times are a guide.
Stretching Wake Windows Too Far
An overtired baby often settles less easily.
Using Actual Age For Premature Babies
Under 2 years, corrected age gives a better picture of development.
Forgetting Safe Sleep For Naps
Every nap, like night sleep, should be on the back on a firm, flat surface with nothing else in the cot.
Accuracy And Limitations
The total-sleep ranges are published recommendations, but the nap times are typical guidance and every baby differs.
What It Does Well
- A clear starting plan from one wake-up time
- Corrected age for premature babies
- Total sleep against recommended ranges
What It Cannot Do
- Know your baby feeding needs
- Account for illness or development
- Replace advice from your doctor or health visitor
How We Calculate Your Baby Sleep Schedule
Baby Sleep Calculator FAQs
How many hours should my baby sleep?
Newborns need about 14 to 17 hours, babies 4 to 12 months 12 to 16 hours including naps, and toddlers 1 to 2 years 11 to 14 hours.
What time should my baby go to bed?
From around 4 months, many babies settle between about 7:00 and 8:30 PM. The best time follows the last nap and the morning wake-up.
How long should wake windows be?
About 45 to 90 minutes for newborns, 2 to 3 hours around 6 to 9 months, and about 5 hours for toddlers on one nap.
When do babies drop to one nap?
Most move to one nap between about 12 and 18 months.
Should I use corrected age for my premature baby?
Yes, for the first 2 years. Subtract the weeks your baby was born early from their age since birth.
Do newborns need a sleep schedule?
No. Under about 4 months, feed on demand and follow tired signs; a routine comes later.
My baby sleeps less than the calculator says. Is that a problem?
Usually not. Healthy babies vary widely. Talk to your doctor if your baby is not feeding or growing well or seems unwell.
What is the safest way for my baby to nap?
On their back, on a firm, flat surface in a cot or bassinet, with no pillows, bumpers, toys or loose blankets.
Sources
- National Sleep Foundation: How many hours of sleep do you really need? (newborns 14 to 17 hours)
- Paruthi et al. Recommended amount of sleep for pediatric populations (AASM consensus) (4 to 12 months 12 to 16 h; 1 to 2 years 11 to 14 h)
- AAP HealthyChildren: Corrected age for preemies (corrected age for the first 2 years)
- NICHD Safe to Sleep: Ways to reduce baby risk (back to sleep, safe sleep space)
- NHS: Helping your baby to sleep (day and night, bedtime routine)
Related Calculators
For bedtimes and wake-up times in both directions, use the main sleep calculator. Explore every sleep timing, sleep need and family sleep tool in one place.
All sleep toolsThis calculator gives a general starting schedule for education. It is not medical advice. Always follow safe sleep guidance and talk to your doctor or health visitor about your baby sleep, feeding or growth. Spotted an error? Let us know.