Sleep Regression Ages: The Complete 4-18 Month Chart
Sleep regressions cluster around five predictable ages in the first year and a half: 4 months, 6 months, 8-10 months, 12 months, and 18 months. Each one is tied to a burst of development — new sleep cycles, new motor skills, new emotions — and each has a slightly different personality. Most last somewhere between one and six weeks.
This is the overview page: one chart with every regression age, what drives each one, how long it typically lasts, and how to tell which one you're in tonight. When you know which regression you're dealing with, we'll point you to the deep-dive guide for that age.
The Sleep Regression Ages Chart (4-18 Months)
| Regression | Typical age window | What's driving it | Typical duration | Temporary or permanent? |
|---|---|---|---|---|
| 4 months | 3-5 months | Sleep cycles mature into adult-like stages | 2-6 weeks | Permanent change in sleep architecture |
| 6 months | 5.5-7 months | Rolling both ways, sitting up, teething, outgrown schedule | 1-2 weeks (up to 6) | Temporary |
| 8 months | 8-10 months | Crawling, pulling to stand, object permanence, 3-to-2 nap transition | 2-6 weeks | Temporary |
| 12 months | 11-13 months | Walking, first words, separation anxiety, flirting with one nap | 1-2 weeks | Temporary |
| 18 months | 17-19 months | Independence and limit-testing, molars, language explosion | 2-6 weeks | Temporary |
Two things worth saying up front:
- The age windows are wide on purpose. Regressions follow brain development, not the calendar. A "4-month regression" at 3.5 months and an "8-month regression" at 9.5 months are both completely normal. For babies born early, go by adjusted age.
- Not every baby hits every regression. Some babies barely register the 6-month or 12-month ones. If your baby is sleeping fine at a "regression age," don't go looking for trouble.
Each Regression at a Glance
4 months: the only permanent one
This is the big one, and it's different in kind from all the others. Around 3-5 months, your baby's simple newborn sleep reorganizes into mature cycles of light and deep sleep — and at the end of every cycle, roughly every 45 minutes, your baby briefly surfaces. A baby who only knows how to fall asleep in your arms will call for you at every one of those surfacings.
The new sleep cycles never go away; the disruption ends when your baby learns to link cycles with less help. That's why this regression gets its own playbook — our full 4-month sleep regression guide covers the survival plan in detail.
Tell-tale signs: waking every 1-2 hours at night, 30-45 minute naps, a formerly "good sleeper" who suddenly isn't.
6 months: the busy-body regression
Around 6 months, several triggers tend to pile up: rolling both ways, sitting up, early teething, and a schedule your baby has quietly outgrown. Sleep itself hasn't changed — your baby is just too busy or too under-scheduled to do it well for a stretch. Once the trigger passes, sleep usually snaps back, as long as you haven't built new habits at 2 a.m. that keep the wakings going. Full details in our 6-month sleep regression guide.
Tell-tale signs: practicing skills in the crib, short "disaster naps," bedtime protest in a baby who used to settle easily.
8-10 months: the emotional one
Whether you call it the 8-, 9-, or 10-month regression, it's the same developmental window. Three things collide: a gross-motor explosion (crawling, pulling to stand), the arrival of object permanence — and with it real separation anxiety — and the drop from three naps to two. It often feels more emotional than earlier regressions because your baby now knows you left the room. Our 8-month sleep regression guide walks through it step by step, including how to handle the 3-to-2 nap transition without wrecking bedtime.
Tell-tale signs: standing in the crib at 3 a.m., crying the moment you leave, refusing the third nap.
12 months: the short, sneaky one
Right around the first birthday, many toddlers hit a brief rough patch: walking (or obsessively practicing it), first words, a fresh wave of separation anxiety, and — the classic trap — suddenly refusing the morning nap. Many parents read that refusal as readiness for one nap. It usually isn't; most toddlers genuinely drop to one nap between 13 and 18 months, and switching too early creates an overtired baby and more night wakings.
What helps: keep offering two naps for now (a quiet rest in the crib counts even if sleep doesn't happen), protect wake windows, and keep bedtime early. This one typically passes in a week or two.
18 months: the toddler-opinion regression
The 18-month regression is less about physical skills and more about personhood. Your toddler now has strong opinions, a word for "no," molars pushing through, and enough memory to protest crib placement as a negotiating tactic. Separation anxiety often resurfaces too.
What helps: boring, loving consistency. Keep the bedtime routine identical every night, offer limited choices before lights-out (which pajamas, which book), respond to night wakings calmly and briefly, and resist introducing new sleep crutches you'll have to unwind later. If molars seem to be the driver, talk to your pediatrician about appropriate pain relief.
How to Tell Which Regression You're In — or If It's Not One at All
Before you label a rough patch a regression, run through this checklist:
| Looks like a regression, but... | What's actually going on |
|---|---|
| Baby is sick, feverish, or pulling at ears | Illness — sleep disruption with congestion, fever, or feeding changes needs a different response |
| Wakings crept in gradually over weeks | Usually a schedule problem: wake windows too short or too long |
| Baby is 7-9 or 13-18 months and fighting one specific nap | Likely a nap transition, not a regression |
| Baby wakes happy and plays quietly | Often just light sleep between cycles — not a problem to fix |
| Rough patch has lasted 8+ weeks with no improvement | Time to look at sleep habits and schedule, and loop in your pediatrician |
A true regression tends to arrive suddenly, in a baby who was sleeping reasonably well, right around one of the chart ages, alongside visible developmental change. If sleep has always been hard, our guide to why your baby is fighting sleep is a better starting point than any regression article.
The Survival Rules That Work for Every Regression
The details differ by age, but the core playbook is the same at 4 months and 18 months:
- Protect wake windows. Overtiredness makes every regression worse. Check that your baby's schedule still fits their age — our guide to decoding wake windows has age-by-age ranges, or use our free nap calculator to get a suggested next nap time from your baby's age and last wake-up.
- Keep the routine boring and identical. A short, predictable bedtime routine is an anchor when everything else is changing.
- Give daytime practice for new skills. Lots of floor time for rolling, crawling, and pulling to stand means less rehearsal at 3 a.m.
- Respond, but don't renovate. Comfort your baby at night — and avoid inventing brand-new habits (a return to rocking fully asleep, a 2 a.m. car ride) that outlast the regression itself.
- Hold your baseline. Regressions end. The families who struggle longest are usually the ones who overhauled a working sleep setup mid-regression.
If night wakings persist well past the regression window and you're ready for a more structured approach, that's when it's worth reading up on formal sleep training — but during the acute weeks of a regression, consistency beats any new method.
One more practical tip: memory is the first casualty of sleep deprivation. If you log sleep as it happens, you can actually see whether this week is worse than last week — or whether the regression is quietly ending. You can track sleep automatically with a free MyBabyTracker account and get wake-window-based nap predictions instead of doing 3 a.m. math.
When to Talk to Your Pediatrician
Most sleep regressions are normal development. Check in with your pediatrician if:
- Sleep disruption comes with fever, ear-pulling, labored breathing, or refusal to feed
- Your baby snores loudly, gasps, or pauses breathing during sleep
- The rough patch lasts more than 6-8 weeks with no improvement
- Your baby seems to be losing skills they previously had, or you have any concern about development
- You are running on empty — your exhaustion and mental health are valid medical topics too
This article is for informational purposes only and is not a substitute for professional medical advice.