Baby Milestones by Month: What's Normal, From Birth to 18 Months

Your buddy’s baby is crawling, and yours is just sitting there looking pleased with himself. The AAP knows the feeling: “It’s even worse when a friend or relative is telling you all the amazing things their child is doing that yours is not.” It also says “the majority of the time children meet their milestones on time.”

This guide uses the CDC’s current milestone lists, the ones your pediatrician works from, and adds what you can do at each stage. It’s general guidance, not medical advice.

The short answer

• What a milestone is: “Developmental milestones are things most children (75% or more) can do by a certain age,” the CDC says.
• When: the CDC lists come at checkup ages: 2, 4, 6, 9, 12, 15 and 18 months.
• Missed one, lost a skill, or uneasy? Tell your pediatrician and ask about screening. Don’t wait.
• Born early? Use corrected age until 2.
• You can call early intervention yourself. No referral or diagnosis needed, and the evaluation is free.

How to read a milestone list (and why other charts disagree)

75%, not 50%. In 2022 the CDC and AAP rewrote the lists so each milestone is something most babies (75% or more) do by that age. Older lists used the average age, and the authors noted that “lists based on median (50th percentile) age milestones might encourage a wait-and-see” approach, since half of normal babies aren’t there yet. Parents of children with disabilities had said they were told to wait.

So a milestone that most babies hit at 11 months and nearly all hit by 16 months was put on the 15-month list. The CDC now says “any missed milestone or concern should prompt discussion or action.”

The 2022 rewrite also:

• Cut the lists from 216 milestones to 159.
• Added checklists at 15 and 30 months.
• Moved some milestones to older ages.
• Dropped the old “warning signs” lists.

It’s a checklist, not a test. The CDC says its materials “are not a substitute for standardized, validated developmental screening tools.” Your pediatrician does the screening.

Crawling isn’t on the list. A 2022 paper by physical therapists says it was dropped because of thin data, inconsistent definitions, and variable timing, and because there’s no evidence that all typically developing children crawl. Some therapists pushed back, and the CDC still suggests floor play that gets babies to “crawl, scoot, or roll.” So crawling is great. It just isn’t a test your baby passes or fails.

Many charts online still use averages or list crawling, and so do some old AAP pages from 2009. If two charts disagree, check the date and the percentage.

Dad’s job: compare your baby with the list, not with your friend’s baby.

Birth to 2 months

There’s no CDC checklist before 2 months. In the first month, the AAP says babies focus best 8 to 12 inches away, prefer a human face to other patterns, and need their head supported. You’ll notice they listen when you speak and watch you as you hold them.

Dad’s job: that 8 to 12 inches is about the distance from your arms to your face, so hold them and talk. See skin-to-skin for dads, and if the connection feels slow, dad not bonding with baby.

By 2 months

Area	What most babies do
Social	Calms down when spoken to or picked up, looks at your face, seems happy to see you, smiles when you talk or smile
Language	Makes sounds other than crying, reacts to loud sounds
Thinking	Watches you as you move, looks at a toy for several seconds
Movement	Holds head up on tummy, moves both arms and legs, opens hands briefly

Dad’s job: talk back when they coo. “You will not spoil your baby by holding or responding to him,” the CDC says. And if the crying gets to you: “Put your baby in a safe place and walk away if you’re getting upset.” Never shake a baby. See how to soothe a crying newborn.

Tummy time is awake and watched only. If your baby gets sleepy, onto their back in a safe sleep space. See tummy time by age.

By 4 months

Area	What most babies do
Social	Smiles on their own to get your attention, chuckles when you try to make them laugh
Language	Makes sounds back when you talk, turns toward your voice
Thinking	Opens mouth at the breast or bottle when hungry, looks at their hands with interest
Movement	Holds head steady when you hold them, holds a toy you put in their hand, brings hands to mouth, pushes up onto elbows on tummy

Dad’s job: floor time every day. The CDC says “Playing on the floor or play mat with your baby every day helps him to move, learn, and explore,” and suggests not keeping babies in swings or bouncy seats too long. Peekaboo counts.

By 6 months

Area	What most babies do
Social	Knows familiar people, likes looking in a mirror, laughs
Language	Takes turns making sounds with you, squeals
Thinking	Puts things in their mouth to explore, reaches for a toy they want
Movement	Rolls from tummy to back, pushes up with straight arms, leans on hands when sitting

Dad’s job: put toys just out of reach so they roll for them, and play the drop game: when the toy hits the floor, give it back. The CDC says that teaches cause and effect. Teeth may show up soon, so see baby teething.

By 9 months

Area	What most babies do
Social	Shy or clingy with strangers, looks when you call their name, reacts when you leave, laughs at peekaboo
Language	Babbles “mamamama” and “bababababa,” lifts arms to be picked up
Thinking	Looks for things that drop out of sight, bangs two things together
Movement	Gets to sitting alone, sits without support, moves things hand to hand, rakes food toward themselves

Notice what isn’t there: crawling.

Dad’s job: copy their sounds and add a word. When you leave, the CDC suggests “a quick and cheerful goodbye instead of sneaking away,” even if they cry, and telling them when you’re back. Stranger shyness is on the list, so a baby who clings to mom isn’t rejecting you.

This is also the first formal screening visit.

By 12 months

Area	What most babies do
Social	Plays games like pat-a-cake
Language	Waves bye-bye, calls a parent “mama,” “dada” or another special name, understands “no”
Thinking	Puts something in a container, looks for things you hide
Movement	Pulls up to stand, walks holding furniture, drinks from an open cup you hold, picks up small things with thumb and finger

Dad’s job: when your baby points, say the word. Let them practice walking by holding your hands. The CDC says “Baby walkers are not recommended,” and “Screen time is not recommended for children younger than 2 years of age.”

Looking ahead: 15 and 18 months

These come from the CDC’s 2022 tables.

By 15 months: copies other children while playing, shows you a toy they like, claps when excited, hugs and kisses you, tries to say 1 or 2 words besides mama or dada, points to ask for things, stacks 2 small objects, takes a few steps alone, feeds themselves some food with fingers.

By 18 months: walks away but checks you’re close, points to show you something, helps you dress them, tries to say 3 or more words besides mama or dada, follows 1-step directions without gestures, copies chores, walks without holding on, scribbles, tries a spoon, climbs on and off a couch.

The 18-month visit includes developmental screening and the first autism screening.

Premature babies: use corrected age

If your baby was born more than 3 weeks early, the AAP says to track development by corrected age until 2. Take your baby’s age in weeks and subtract the weeks they came early. The AAP’s example: a baby born at 32 weeks, now 4 months old, has a corrected age of 2 months.

“By 2 years of age, most children have caught up to the typical milestone range,” the AAP says, and some need extra support for longer. Ask about early intervention. If relatives’ comments get to you, the AAP says parents are often frustrated by well-meaning family and friends.

Checkups and screening: what the pediatrician does

The pediatrician checks development at every visit. The AAP also recommends formal screening “at the 9-, 18-, and 30-month health supervision visit,” and autism screening at 18 and 24 months, plus any time a parent raises a concern. One HealthyChildren page adds 48 months. “Screening for autism is not the same as diagnosing autism,” the AAP adds.

Dad’s job: go to at least one checkup. The AAP says to bring your top three to five questions. The CDC suggests these:

• Is there anything your baby does or doesn’t do that worries you?
• Has your baby lost any skills they once had?
• Was your baby born early, or do they have special health needs?

The CDC’s free Milestone Tracker app uses the same lists and makes a summary you can share with your doctor. See best apps for new dads.

When to talk to the pediatrician

• Your baby hasn’t hit a milestone for their age, or corrected age.
• Your baby has lost a skill they used to have.
• Their head and neck seem hard to hold steady, or their muscles seem stiff or floppy.
• They struggle to roll, sit or walk.
• Something just feels off.

“You know your child best. Don’t wait,” the CDC says. The AAP’s honest version: “Usually, a child who is not doing certain skills will catch up to other children their age. Sometimes, it is a sign of a health condition.” And if you’re not taken seriously, the AAP says to get a second opinion.

Early intervention: you can call them yourself

Early intervention is a federal program run by each state under Part C of the Individuals with Disabilities Education Act, for children from birth to age 3. “Early intervention is available in every state,” the AAP says.

• No referral needed. “Anyone can refer a child to EI,” the AAP says, parents included. “The child does not even need a diagnosis.”
• The evaluation is free. Federal rules say parents can’t be charged for evaluation and assessment. Services can cost something depending on the state, but every state must provide some free.
• It moves on a clock. The evaluation and plan must be done within 45 days of the referral.
• What to say: that you’d like your child evaluated under Part C of IDEA.
• Where to call: the CDC lists every state’s program at cdc.gov/FindEI.

Why it matters: the 2022 paper found “less than a quarter of children with DDs receive early intervention services before age 3 years.” The CDC says children who get help early have better outcomes.

Dad’s job: if you’re worried, make the call. It costs you a phone call, and the evaluation costs nothing.

FAQ

My friend’s baby is crawling and mine isn’t. Should I worry?

Crawling isn’t on the CDC’s current lists. At 9 months the CDC lists sitting without support and getting to sitting alone, and at 12 months pulling up to stand and walking while holding furniture.

What does 75% mean on the CDC checklist?

Most babies (75% or more) do it by that age. So a missed one is worth raising with your pediatrician, not waiting on.

How do I calculate corrected age, and until when?

Subtract the weeks your baby was born early from their actual age. The AAP says to use it until age 2.

When does the pediatrician screen for delays and autism?

General screening at 9, 18 and 30 months, autism screening at 18 and 24 months, and any time you raise a concern.

Do I need a doctor’s referral for early intervention?

No. Parents can contact their state program directly, and the evaluation is free.

What if my baby loses a skill they had?

Tell your pediatrician. The CDC lists losing skills as a reason to act early.

Is the CDC Milestone Tracker app a screening test?

No. It’s a checklist to share with your doctor, not a substitute for screening.

Sources

• CDC Learn the Signs. Act Early.: Milestones at 2 months, 4 months, 6 months, 9 months, 12 months, 15 months and 18 months; Milestone Tracker app; Find early intervention
• Zubler et al., Evidence-informed milestones for developmental surveillance tools, Pediatrics 2022; Kretch et al., Crawling and the CDC milestones, Pediatric Physical Therapy 2022
• American Academy of Pediatrics (HealthyChildren.org): Corrected age for preemies, Assessing developmental delays, Early intervention, Autism screening, Preemie milestones, Physical development, Well-child visits; AAP (aap.org): Developmental surveillance and screening
• U.S. Department of Education: 34 CFR Part 303 (sections 303.21, 303.303, 303.310, 303.521); Center for Parent Information and Resources: Overview of early intervention; ECTA Center: Part C state coordinators