4 Month Old Sleep Schedule
Complete sleep guide for 16-20 week old babies: wake windows, sample schedules, navigating the 4-month regression, and evidence-based sleep strategies.
Managing the 4-month regression + building sleep skills
Evidence-based guide reviewed by pediatric sleep experts
Last updated: January 20, 2025
⚠️ Medical Disclaimer: This information is for educational purposes only and is not medical advice or professional sleep consultation. Every baby is unique. Always consult your pediatrician about your baby's specific sleep, health, and safety needs, especially regarding the 4-month regression. If you have concerns about your baby's breathing, development, feeding, or sleep patterns, seek professional guidance immediately.
4 Month Sleep Schedule Guidelines
What's New at 4 Months (16-20 Weeks)?
Sleep cycles mature into adult-like patterns. You may notice frequent night wakings, short naps, and increased fussiness. This is permanent maturation, not a phase to "wait out."
Many babies consolidate from 4 to 3 naps during this period. This may happen gradually or suddenly. Total daytime sleep: 3.5-4.5 hours.
Due to the regression, nighttime sleep may become disrupted temporarily. Total night sleep may be 10-12 hours but feel fragmented. Patience and consistent routines may help.
Babies are more interactive, aware of surroundings, and may resist sleep due to FOMO (fear of missing out). Boring sleep environment becomes critical.
Quick Reference: 4 Month Old Sleep (16-20 Weeks)
📚 Data Sources:
Guidelines adapted from:
- American Academy of Pediatrics (AAP)
- National Sleep Foundation
- Pediatric sleep research (see References section below)
⚕️ Consult Your Pediatrician: These are general planning guidelines. Every baby is different. If you have concerns about your baby's sleep, feeding, or development, please consult your healthcare provider.
Why Use Wake Windows Instead of a Fixed Schedule?
You might be wondering: If this is a sleep schedule page, why am I seeing a wake window calculator?
Here's the truth: Even though 4 month olds (16-20 weeks) have more predictable sleep patterns, daily wake times can still vary by 15-30 minutes. A rigid "7:00 AM wake, 9:00 AM nap" schedule can be frustrating, especially during the 4-month regression when patterns are shifting.
What ARE Wake Windows?
Wake windows are the amount of time your baby can comfortably stay awake between sleeps. For 4 month olds, this is typically 90-120 minutes (1.5-2 hours), though the regression may temporarily affect this.
Instead of watching the clock for specific nap times, you watch how long baby has been awake and respond to their sleep cues. This is more flexible and adapts to your baby's actual rhythm each day, while still giving you structure.
How the calculator below helps: Enter your baby's wake-up time, and it will show you the window when they'll likely need their next nap (based on age-appropriate wake windows for 4 month olds). This adapts to YOUR baby's actual day, not a rigid schedule.
Bottom line: At 4 months, wake windows remain the most flexible approach, especially during the regression. This method adapts as your baby's needs change during this developmental period.
Next Nap Window Calculator
What's Normal at 4 Months
If your baby was sleeping well and suddenly has disrupted sleep, this may signal the regression. Patterns may stabilize somewhat within 2-4 weeks as baby adjusts to new sleep cycles.
A typical pattern: morning nap (1-1.5 hrs), midday nap (1-2 hrs), late afternoon nap (30-60 min). Some babies may still take 4 naps. Total daytime sleep: 3.5-4.5 hours.
This reflects the difficulty connecting sleep cycles during the transition to adult-like sleep patterns. Longer naps may return as baby adjusts, though some babies consolidate to fewer, longer naps.
You may see frequent wakings even if your baby was sleeping through before. Total night sleep typically remains 10-12 hours, but the pattern may feel disrupted. This is the regression at work.
Babies may fight sleep, seem restless, or require more soothing. Consistent routines, appropriate wake windows, and patience may help during this transition.
Remember: The 4-month regression is normal and reflects permanent development. While it may feel disruptive, it's a sign that your baby's sleep architecture is maturing. Every baby's experience is different.
Wake Windows Guide: 4 Month Old (16-20 Weeks)
Age-Specific Wake Windows
90-110 minutes (1.5-1.83 hours). Still working through early regression, may be slightly shorter if sleep is disrupted.
90-120 minutes (1.5-2 hours). Middle of regression period; wake windows may be variable.
90-120+ minutes (1.5-2+ hours). As baby adjusts to new sleep patterns, wake windows may gradually lengthen.
During the 4-Month Regression:
- •First wake window: May be 75-90 min (baby may be tired after night wakings)
- •Subsequent wake windows: 90-110 min typically
- •Last wake window before bed: May extend to 100-120+ min
- •Flexibility is key: Watch baby's cues more than the clock during regression
Understanding the 4-Month Sleep Regression
The 4-month regression is a permanent change in sleep architecture—not a temporary phase. Your baby's sleep cycles are maturing from newborn patterns (50-minute cycles) to adult-like patterns (90-minute cycles). This typically happens between 16-20 weeks.
Signs Your Baby May Be Experiencing the Regression:
What May Help During the Regression:
Maintain consistent routines: Predictable bedtime routines may provide comfort during this disruptive period.
Use wake windows flexibly: Watch your baby's cues more than the clock, as they may need slightly different wake windows during the regression.
Optimize the sleep environment: Dark, quiet, cool room may help your baby settle more easily.
Practice patience with short naps: As sleep cycles mature, babies may connect cycles better over time, but short naps may persist for a period.
Note: The regression typically lasts 2-4 weeks, though individual experiences vary. Sleep patterns may gradually stabilize as your baby adjusts to the new sleep architecture, though some changes (like shorter total sleep need) may be permanent.
Sample Schedules for 4 Month Olds
These are examples of what a 4-month schedule may typically look like. Remember: all babies are different, especially during the regression. Use wake windows and baby cues as your guide.
Example 1: Early Riser with 3 Naps
Notes on This Schedule:
- Wake windows: ~90-100 min between sleep periods
- Total daytime sleep: ~3.5-4 hours
- Night sleep: 10-12 hours (may include 0-2 feeds)
- During regression, naps may be shorter (30-45 min each)
- This assumes no night feeds; adjust if your baby feeds at night
Example 2: Later Riser with 4 Naps
Notes on This Schedule:
- Wake windows: ~90-110 min between most sleep periods
- Total daytime sleep: ~4-4.5 hours with 4 naps
- Night sleep: 10-12 hours (may include 0-2 feeds)
- During regression, some naps may be 30 min (one cycle)
- Catnap timing may shift as baby transitions to 3-nap schedule
Important: These are examples only. Your baby's schedule may look quite different, especially during the 4-month regression when patterns are shifting. Use wake windows and observe your baby's sleep cues to determine optimal nap timing for your unique situation.
Safe Sleep Guidelines for 4 Month Olds
Always place baby on back to sleep. Once baby begins to roll both ways, you may allow them to find their own position, but always start on back.
Use a firm crib, bassinet, or play yard that meets safety standards. Avoid soft surfaces, pillows, blankets, or bumpers.
Baby's sleep space in your room for at least 6 months (ideally 1 year). This may help with feeding and monitoring.
Keep room at comfortable temperature. Use sleep sack or wearable blanket instead of loose blankets. Avoid overdressing.
Offering a pacifier at bedtime may help reduce SIDS risk. Don't force it if baby refuses.
If your baby is showing signs of rolling, it's time to stop swaddling (typically around 3-4 months). Transition to a sleep sack or sleep suit. If baby shows strong roll reflex, discontinue swaddling.
Video monitors are fine, but products claiming to reduce SIDS aren't recommended by AAP. Standard monitoring (sounds and visuals) is sufficient.
Questions about safe sleep? See AAP guidelines or discuss any concerns with your pediatrician. Safe sleep practices support both SIDS prevention and healthy sleep development.
Research & Evidence Base
All recommendations on this page are based on peer-reviewed research and authoritative guidelines from leading medical organizations:
American Academy of Pediatrics (AAP) Task Force on Sudden Infant Death Syndrome
SIDS and Other Sleep-Related Infant Deaths: Updated 2022 Recommendations
Pediatrics, 2022. The most current authoritative source for safe sleep guidelines.
National Sleep Foundation Sleep Duration Recommendations
Sleep Duration Recommendations by Age
Provides age-specific sleep duration guidelines based on research consensus.
Mindell et al. on Infant Sleep Patterns
Research on developmental patterns in infant sleep, wake windows, and regressions.
Provides evidence for wake window guidelines and regression characteristics.
Last updated: January 20, 2025. This page is regularly reviewed to ensure alignment with the latest pediatric sleep research and AAP guidelines.