Infant Developmental Milestones by Month: A Pediatrician's First-Year Guide (0-12 Months)

Last medically reviewed: June 2026

Babies develop along four tracks at once: how they move, how they communicate, how they connect with people, and how they think. The CDC's 2022 update changed how those milestones are described. Each one is now "what most babies (about 3 in 4) do by a given age," not a pass-or-fail deadline. Earlier or later is usually normal, and one missed item in one month is rarely a reason to worry. This guide walks through what most babies do at each month from 1 to 12 and when to call your pediatrician.

How Do Developmental Milestones Work in the First Year?

Pediatricians watch four areas of your baby's development:

• Gross motor skills are big movements like rolling, sitting, and standing.
• Fine motor skills are small hand movements like picking up food.
• Language and communication covers cooing, babbling, and first words.
• Social-emotional and cognitive are how your baby connects with you and how they learn, think, and figure things out.

The CDC's 2022 revision moved every milestone to "what most babies (about 75%, or 3 in 4) do by that age." The goal was to lower false alarms while still catching real delays. A baby who picks up a skill a few weeks earlier or later than this guide is almost always developing normally.

You may see slightly different ages in different places. CDC updated its checklists in 2022 to show what most babies do by each age, while some AAP resources still list older average ages. Both are normal-range guides, not pass-or-fail tests.

A note for parents of premature babies: judge milestones by your baby's corrected age (sometimes called adjusted age). That is your baby's age minus the weeks they were born early. A baby born 2 months early would be expected to hit a "6-month" milestone around 8 months on the calendar. Pediatricians use corrected age until about age 2.

Baby Milestones Month-by-Month Chart (0-12 Months)

1 Month Old Milestones

In the first weeks, your baby's job is to feel safe and get organized. Most babies calm when comforted and start to focus briefly on a face.

• Gross motor: Moves both arms and both legs. Lifts head briefly during tummy time. Has a strong reflexive grasp.
• Fine motor: Hands are usually closed in fists, opening at random.
• Language: Makes small throaty sounds. Startles to loud sounds.
• Social-emotional: Calms down when comforted. Looks toward voices and faces.
• Cognitive: Stares at faces and high-contrast objects.

The CDC does not publish a separate 1-month checklist. This list follows the AAP HealthyChildren sequence for the early weeks. If your baby is feeding well, gaining weight, and reacting to sound and light, they are on track.

2 Month Old Milestones

The 2-month visit is the first CDC checkpoint. The big milestone most parents notice is the first social smile.

• Gross motor: Holds head up when on tummy. Moves both arms and both legs.
• Fine motor: Opens hands briefly.
• Language: Makes sounds other than crying. Reacts to loud sounds. (Early cooing usually starts in the next few weeks. For a deeper look, see our guide to cooing in infants.)
• Social-emotional: Smiles when you talk to or smile at them. Looks at your face. Seems happy to see you.
• Cognitive: Watches you as you move. Looks at a toy for several seconds.

If you are not yet seeing a social smile by 2 months, bring it up at the visit. It is one of the items pediatricians check.

3 Month Old Milestones

By around 3 months, social and language skills usually take off.

• Gross motor: Raises head and chest during tummy time. Pushes up on forearms. Opens and shuts hands.
• Fine motor: Swipes at dangling toys.
• Language: Coos and makes gurgling sounds. Begins to imitate some sounds.
• Social-emotional: Smiles spontaneously, especially at people. Enjoys play.
• Cognitive: Watches faces closely. Follows moving objects. Recognizes familiar people at a distance.

There is no CDC checklist for 3 months. This list reflects the AAP HealthyChildren birth-to-3-month band, so a few items overlap with the 2-month list.

4 Month Old Milestones

Four months is the next CDC checkpoint and the first standardized concern point in pediatric care. Bring questions to this visit.

• Gross motor: Holds head steady without support when you hold them. Pushes up onto elbows or forearms when on tummy.
• Fine motor: Holds a toy when you put it in their hand. Uses arms to swing at toys. Brings hands to mouth.
• Language: Makes sounds like "oooo" and "aahh" (cooing). Makes sounds back when you talk. Turns head toward the sound of your voice.
• Social-emotional: Smiles on their own to get your attention. Chuckles (not yet a full laugh). Looks, moves, or makes sounds to keep your attention.
• Cognitive: If hungry, opens mouth when they see breast or bottle. Looks at hands with interest. (Sleep is shifting too around now. Many parents notice the four-month sleep change; see our guide to baby sleep cycles and milestones for what is normal.)

5 Month Old Milestones

Around 5 months, most babies are getting ready to roll and reaching for everything.

• Gross motor: Rocks on tummy and kicks legs. May roll from tummy to back. Has better head control when held.
• Fine motor: Brings feet to mouth. Reaches with both hands.
• Language: Babbles with expression. May add early consonant-like sounds.
• Social-emotional: Enjoys social play. Smiles and vocalizes to engage. May show early stranger awareness.
• Cognitive: Tracks objects well. Explores toys with the mouth.

The CDC does not list 5-month checkpoints. This list follows the AAP HealthyChildren 4-to-7-month band, so timing can vary by a few weeks.

6 Month Old Milestones

Six months is a CDC checkpoint and one of the busiest months for new skills.

• Gross motor: Rolls from tummy to back. Pushes up with straight arms on tummy. Leans on hands to support themselves when sitting.
• Fine motor: Reaches to grab a toy they want.
• Language: Takes turns making sounds with you. Blows raspberries. Makes squealing noises.
• Social-emotional: Knows familiar people. Likes to look at themselves in a mirror. Laughs.
• Cognitive: Puts things in their mouth to explore them. Closes lips to show they do not want more food. (Most babies are also ready to start solids around this time. See our first-year nutrition guide.)

You may notice that AAP materials list a few extra skills at 6 months (rolling both ways, hand-to-hand transfer, and consonant babbling like "ba" or "da") while CDC lists only "rolls tummy to back." Both are normal-range guides. For a deeper look at this month, see our full 6-month milestone guide.

7 Month Old Milestones

Around 7 months, babies usually sit more steadily and become little explorers.

• Gross motor: Sits with little or no support. Bears weight on legs when held.
• Fine motor: Transfers objects hand to hand. Rakes small objects toward themselves.
• Language: Babbles chains of sounds. Responds to their own name. Uses voice to show pleasure or displeasure.
• Social-emotional: Responds to other people's emotions. Clear preference for caregivers.
• Cognitive: Explores objects by mouthing, shaking, and banging. Finds partially hidden objects (early object permanence).

The CDC does not list 7-month checkpoints. This list follows the AAP HealthyChildren 4-to-7-month band.

8 Month Old Milestones

Around 8 months, many babies start to feel separation more strongly and move toward independence.

• Gross motor: Sits steadily without support. May rock on hands and knees. Some begin to scoot or pull to stand.
• Fine motor: Picks up larger objects with a whole-hand grasp.
• Language: Babbles "mama" or "dada" without yet meaning a parent. Responds to familiar words.
• Social-emotional: May show stranger anxiety and clinginess. Plays interactive games.
• Cognitive: Looks for objects that fall out of sight. Bangs objects together.

There is no CDC 8-month checklist. This list follows the AAP HealthyChildren 8-to-12-month band, so a few items overlap with the 9-month list.

9 Month Old Milestones

Nine months is a CDC checkpoint and the first standardized developmental screening point recommended by the AAP. Bring any concerns to this visit.

• Gross motor: Gets to a sitting position by themselves. Sits without support.
• Fine motor: Moves things from one hand to the other. Uses fingers to rake food toward themselves.
• Language: Makes many different sounds like "mamamama" and "babababa." Lifts arms up to be picked up.
• Social-emotional: Is shy, clingy, or fearful around strangers. Shows several facial expressions like happy, sad, angry, and surprised. Looks when you call their name. Reacts when you leave. Smiles or laughs when you play peek-a-boo.
• Cognitive: Looks for objects when dropped out of sight. Bangs two things together.

10 Month Old Milestones

By around 10 months, many babies are pulling to stand and starting to copy what you do.

• Gross motor: Pulls to stand. Cruises along furniture (walks while holding on).
• Fine motor: Refines the pincer grasp (thumb and finger). Picks up small bits of food.
• Language: Says "mama" or "dada" with growing meaning. Understands "no." Uses simple gestures.
• Social-emotional: Plays interactive games like peek-a-boo and pat-a-cake. Waves. Repeats sounds and actions for attention.
• Cognitive: Looks for hidden objects with more confidence (object permanence is getting stronger).

There is no CDC 10-month checklist. This list follows the AAP HealthyChildren 8-to-12-month band.

11 Month Old Milestones

Around 11 months, babies often look like little copycats.

• Gross motor: Stands briefly without support. Cruises confidently. May take first independent steps at the early end of the range.
• Fine motor: Picks up small bits of food cleanly. May try to use a spoon or cup.
• Language: May say one word besides "mama" or "dada." Babbles with the rise and fall of speech. Follows simple one-step requests when paired with a gesture.
• Social-emotional: Strong attachment to caregivers. Imitates others. May test your reactions.
• Cognitive: Finds hidden objects easily. Begins to use objects correctly, like holding a cup to the mouth or a brush to the hair.

There is no CDC 11-month checklist. This list follows the AAP HealthyChildren 8-to-12-month band.

12 Month Old Milestones

The first birthday is a CDC checkpoint and a big language moment. Important: independent walking is not a 12-month milestone. At 12 months, CDC lists cruising (walking while holding on to furniture). Most babies take their first independent steps by about 15 months, with a typical range of 9 to 18 months.

• Gross motor: Pulls up to stand. Walks while holding on to furniture (cruising).
• Fine motor: Drinks from a cup without a lid as you hold it. Picks things up between thumb and pointer finger (pincer grasp).
• Language: Waves bye-bye. Calls a parent "mama" or "dada" or another special name (first word). Understands "no" (pauses or stops). (For practice ideas, see our guide to baby talking milestones and ten simple strategies to help your baby develop speech.)
• Social-emotional: Plays games with you like pat-a-cake.
• Cognitive: Puts something in a container, like a block in a cup. Looks for things you hide, like a toy under a blanket.

When Should My Baby Roll Over, Sit Up, Crawl, and Walk?

Big motor milestones are the ones parents ask about most. Here is the typical range for each.

A note on crawling: it is one of the most-searched baby milestones, and many babies do it between 7 and 10 months. But crawling is not on the CDC checklist. Skipping it (going straight to scooting, pulling up, or walking) is not a delay on its own.

"In our telehealth visits, the milestone question we hear most is whether a baby who isn't crawling or walking 'on time' is behind. Most often, that baby is developing well within the normal range."

Dr. Melissa Tribuzio, MD, Board-Certified Pediatrician

Developmental Red Flags: When to Talk to Your Pediatrician

Most babies who hit one milestone late are still on track. A few signs deserve a call this week, and one deserves a same-day call at any age.

At any age, urgent: Loss of a skill your baby once had (babbling that stops, the social smile fading, or sitting that disappears). Skill regression always needs prompt evaluation. Call your pediatrician right away.

At any age: No reaction to loud sounds, no turning toward voices, or no eye contact and tracking. These call for a prompt hearing or vision check.

The warning boxes above each monthly section list the red flags for 4, 6, 9, and 12 months. The CDC's "Learn the Signs. Act Early." program puts these in plain language.

A few framing notes:

• Missing one item in one month is rarely a problem. A pattern across more than one area, or losing a skill, is what gets attention.
• "Not crawling" is not a red flag by itself. Mention it only if your baby is also not pulling to stand, cruising, or moving in any other way by 12 months.
• "Not babbling" is a 9-month flag, not a 6-month flag. The CDC moved consonant babbling like "mama" and "baba" to the 9-month checklist in 2022.

What If My Baby Is Behind on Milestones?

If something feels off, trust it. Call your pediatrician and ask. Most concerns turn out to be normal variation, and the visit gives you a clear answer instead of weeks of worry.

Pediatricians use two tools to track development:

• Developmental surveillance happens at every well-child visit. Your pediatrician asks how things are going and watches your baby play.
• Developmental screening uses a standardized questionnaire (often the ASQ-3). AAP recommends screening at the 9-, 18-, and 30-month visits, with autism-specific screens at 18 and 24 months.

If screening or your pediatrician's exam suggests a delay, early intervention is the next step. Services are available in every U.S. state for children under 3, and no child is turned away for inability to pay. Evaluation, IFSP development, and service coordination are always free under IDEA Part C. Some states then provide therapies and home visits at no cost; others use a sliding-scale fee based on family income. Parents can self-refer without a doctor's referral. The earlier a delay is found, the more support a baby can get.

What's Next After 12 Months?

The toddler year brings walking, more words, and big personality shifts. For what comes next, see our 2-year-old developmental milestones guide. For other ages and topics, browse our milestones and development hub.

Frequently Asked Questions

What are the four areas of infant development?

Pediatricians track four areas: motor (gross motor like rolling and sitting, and fine motor like picking up food), language and communication, social-emotional, and cognitive (learning and problem-solving).

What milestones should a baby hit at each month from 1 to 12?

Use the chart above. CDC checklists cover 2, 4, 6, 9, and 12 months. For in-between months, the AAP HealthyChildren developmental sequence is the best guide. Each item is "what most babies (about 75%) do by that age," not a pass-or-fail rule.

When do babies smile, coo, roll over, sit up, crawl, pull to stand, and walk?

Most babies smile socially around 2 months and coo around 4 months. They roll tummy-to-back around 6 months and sit without support around 9 months. Crawling falls between 7 and 10 months (if a baby crawls at all). Pulling to stand and cruising come around 12 months. First independent steps usually happen by about 15 months, with a typical range of 9 to 18 months.

When do babies say their first word or start babbling?

Most babies babble strings of sounds like "mamamama" around 9 months. The first true word usually comes around 12 months.

Is it normal for my baby to be ahead on some milestones and behind on others?

Yes. Babies often move fast in one area and slower in another. A pattern of delays across more than one area, or losing a skill, is what pediatricians watch for.

What are the developmental red flags at 2, 4, 6, 9, and 12 months?

CDC publishes red flags at each checkpoint. The warning boxes in this guide list them for 4, 6, 9, and 12 months. At any age, the most urgent red flag is losing a skill a baby once had.

When should I call my pediatrician about a delay?

Call right away if your baby loses a skill at any age. Call the same week if a CDC red flag appears at a checkpoint. Otherwise, bring it up at the next well-child visit.

What does "corrected age" mean for premature babies?

Corrected age is your baby's age minus the weeks they were born early. A baby born 2 months early would be expected to hit a "6-month" milestone around 8 months on the calendar. Pediatricians use it until about age 2.

What happens at a developmental screening?

A screening uses a short validated questionnaire (often the ASQ-3). AAP recommends one at the 9-, 18-, and 30-month visits, with autism-specific screens at 18 and 24 months.

What is early intervention and how do I get it?

Early intervention is a federally funded program of services (like speech or physical therapy) for children under 3 with a developmental delay, available in every U.S. state. Under IDEA Part C, evaluation and service coordination are always free, and no child can be turned away for inability to pay. Therapies and home visits are free in some states and offered on a sliding-scale fee based on family income in others. You can self-refer without a doctor's referral.

Last medically reviewed: June 2026. Updated when new AAP or CDC milestone guidance is published.

This article is for general education and is not a substitute for medical advice. If you have a concern about your baby's development, talk to your pediatrician.