Baby Milestones by Month: Your Baby's First Year of Development
From the first little smiles to babbling, sitting and exploring everything within reach, here's what you may notice as your baby grows, and how to know when a developmental concern is worth discussing.
One day, your baby seems perfectly content staring at your face. A few weeks later, they're smiling back, reaching for toys and discovering that their own feet are fascinating. Before long, they're trying to sit, grabbing food from their tray or pulling themselves up to see what's happening around them.
The first year brings remarkable changes, often in ways that are easy to overlook until you look back at an old photograph or video.
It's also a year when parents can find themselves comparing development. You might hear that another baby rolled at four months, started crawling at seven months or took their first steps before their birthday. Suddenly, a milestone that hadn't crossed your mind becomes something you're watching for every day.
Developmental milestones are useful because they help us notice how babies are growing, not because every child is supposed to follow an identical schedule.
This guide explains what to look for during your baby's first 12 months, which milestones are included in official CDC checklists, and how simple everyday play can support development.
Baby Milestones by Month: Quick Reference
Babies develop across several areas at once. Movement and coordination are important, but so are communication, learning, relationships and play.
The table below provides an overview of the first year. The five CDC checkpoint ages are 2, 4, 6, 9 and 12 months. Other months describe how development may be progressing between those checkpoints.
Age | Developmental focus |
Newborn | Responding to touch, voices and close interaction |
1 month | Increasing alertness and interest in familiar faces |
2 months — CDC checkpoint | Social smiles, sounds beyond crying and lifting the head during tummy time |
3 months | More social interaction and practice controlling head movements |
4 months — CDC checkpoint | Cooing, chuckling, steady head control and reaching toward toys |
5 months | Exploring hands and objects, practicing rolling and reaching |
6 months — CDC checkpoint | Laughing, reaching for desired toys, rolling tummy to back and supporting the body while sitting |
7 months | Practicing balance, handling toys and exploring sounds |
8 months | Growing curiosity, hand coordination and movement between positions |
9 months — CDC checkpoint | Sitting without support, responding to their name and searching for dropped objects |
10 months | Exploring new ways to move, communicate and solve simple problems |
11 months | Practicing gestures, grasping small objects and supported standing |
12 months — CDC checkpoint | Waving, using a special name for a parent, pulling to stand and cruising along furniture |
The non-checkpoint rows are broad descriptions of developing abilities, not milestones that every baby should achieve during that specific month.
For official checklists, use the CDC's Developmental Milestones resource.
What Counts as a Developmental Milestone?
A developmental milestone is a skill or behavior that gives clues about how a child is growing. Pediatric professionals generally consider four connected areas:
Social and emotional development includes smiling, showing interest in familiar people, responding to interaction and playing simple games.
Language and communication includes making sounds, responding to voices, babbling, gestures and eventually meaningful words.
Cognitive development involves attention, exploration, memory and early problem-solving, such as looking for a dropped toy.
Movement and physical development includes head control, reaching, rolling, sitting, grasping, standing and eventually walking.
The CDC's current milestone checklists identify skills that 75% or more of children can do by a particular age. They're designed to help parents and healthcare professionals notice possible concerns earlier, rather than simply waiting to see whether a child catches up.
They are not a diagnostic test and do not replace standardized developmental screening.
Newborn to 1 Month: Getting to Know the World
In the first several weeks, your newborn is adjusting to a world full of light, sound, touch and movement. Much of their time is spent feeding, sleeping and responding to basic needs, but that doesn't mean development is standing still.
Your baby may turn toward familiar voices, briefly focus on faces held nearby and gradually spend longer periods looking around. Their movements can appear jerky and uncoordinated because the nervous system is still developing.
Rather than trying to introduce formal activities, focus on close interaction. Hold your baby, talk to them during feeds and diaper changes, and give them supervised opportunities to spend time on their tummy while awake. Start with short periods that suit their comfort and gradually increase them.
For a fuller picture of the early weeks, our Newborn Sleep: What to Expect in the First 12 Weeks explains why feeding and sleep can still feel unpredictable during this stage.
2 Months: Smiles, Sounds and Early Head Control
Official CDC milestone checkpoint
Around two months, social interaction may begin to feel more mutual. Your baby might look directly at your face, appear happy when you approach and smile when you talk or smile at them. These moments can make even the most ordinary diaper change feel like a conversation.
The CDC also lists making sounds other than crying and reacting to loud sounds among the milestones for this age. During supervised tummy time, many babies can lift their heads, and you may notice them moving both arms and legs or briefly opening their hands.
How to Encourage Development
Try talking to your baby and pausing as though you're waiting for an answer. Their response might be a small movement, a facial expression or a sound. You can also place a simple, age-appropriate toy where they can see it and watch whether they pay attention.
You don't need a toy collection full of lights and sounds. Your face, voice and regular interaction are already valuable.
3 Months: More Connection and Curiosity
Three months is a period of growing practice rather than a separate CDC milestone checkpoint. Some babies become more expressive, spend longer looking at people and gradually gain confidence holding their heads up.
Your baby may enjoy watching you move around the room or become especially interested when you sing a familiar song. They may also start bringing their hands together or spending more time examining the objects around them.
You can support this stage with face-to-face interaction, supervised floor play and short opportunities to reach toward age-appropriate toys. Pay attention to your baby's reactions. Looking away, fussing or becoming tired can mean it's time for a quieter activity.
The goal is not to speed up development before the four-month checkpoint. It's to create comfortable opportunities to explore.
4 Months: Reaching, Cooing and Building Strength
Official CDC milestone checkpoint
By four months, many babies are becoming enthusiastic participants in social interaction. They may smile to get your attention, chuckle when you try to make them laugh and make sounds back when you speak to them.
The CDC also identifies several developing physical skills at this age: holding the head steady when supported upright, bringing hands to the mouth, holding a toy placed in the hand and pushing up onto forearms during tummy time.
You may notice your baby studying their hands with surprising concentration. This is part of learning how their body moves and interacts with the world.
How to Encourage Development
Offer easy-to-grasp toys during supervised play and give your baby room to move their arms and legs freely. Talk through everyday routines, repeat the sounds they make and allow time for them to respond.
If your baby seems uninterested in a particular toy, try something simpler. A familiar voice and a little back-and-forth interaction can be just as engaging.
5 Months: Discovering Hands, Toys and Movement
At five months, many babies are becoming more deliberate about reaching and handling objects. You might notice your baby grabbing a toy, bringing it closer to their face or trying different ways to hold it.
Some babies begin rolling during this period, while others are still building the strength and coordination needed for the movement. Rolling is not something every baby must accomplish at exactly five months.
Offer supervised floor time on a firm, safe surface where your baby can move freely. Place an interesting toy within reach and allow them to experiment with moving toward it.
If your baby shows signs of rolling, stop swaddling for sleep and continue following safe sleep guidance. Practice movement during awake play, not by putting your baby in an unsafe sleeping position.
6 Months: Rolling, Laughing and Exploring
Official CDC milestone checkpoint
By six months, many babies enjoy making their presence known. The CDC includes laughing, taking turns making sounds, blowing raspberries and making squealing noises among developmental skills for this stage.
You may also notice your baby reaching for a toy they want, exploring objects with their mouth and becoming increasingly curious about what's happening nearby.
In physical development, the CDC lists rolling from tummy to back, pushing up with straight arms during tummy time and leaning on the hands for support while sitting.
Sitting independently without support is not a required CDC six-month milestone. That skill appears on the nine-month checklist.
How to Encourage Development
Let your baby explore safe, easy-to-hold objects while you remain close and attentive. Play simple imitation games, respond to their noises and provide supported sitting practice without forcing them into positions they cannot maintain safely.
Around this stage, many families also begin thinking about complementary foods. Developmental readiness matters more than the calendar alone. Our Starting Solids: A Practical Guide to Baby's First Foods explains readiness signs and how to begin safely.
7 Months: Practicing Balance and Coordination
At seven months, daily play can begin to look much more active. Some babies spend longer sitting with support, pass time exploring toys or become determined to reach something just outside their grasp.
Others are still concentrating on rolling, developing balance or learning how to use their hands more effectively. The specific order of these skills can vary.
You can make playtime interesting by placing a couple of suitable toys nearby, letting your baby explore different textures and talking about what they're doing. Avoid small parts and objects that could cause choking.
It's tempting to compare sitting or crawling progress with other babies at this stage, but a single skill doesn't tell the whole developmental story. Look at how your baby is progressing overall and raise concerns with your pediatrician.
8 Months: Understanding More About People and Objects
Around eight months, babies may become increasingly aware of familiar people and everyday routines. Some begin reacting differently to unfamiliar faces or becoming upset when a favorite caregiver steps away.
You may also notice a stronger interest in objects. Dropping a toy, retrieving it and repeating the experiment can become fascinating activities. Handling toys with both hands may become more coordinated as your baby approaches the nine-month checkpoint.
Try simple games such as hiding a toy partly under a cloth while your baby watches, then encouraging them to find it. Choose age-appropriate objects and supervise closely.
Don't worry if your baby finds a simple household interaction more exciting than an expensive developmental toy. Ordinary play offers plenty of opportunities to learn.
9 Months: Sitting, Babbling and Looking for Hidden Objects
Official CDC milestone checkpoint
Nine months is an important developmental screening age, and the CDC checklist includes skills across all four areas of development.
Many babies at this age look when their name is called, show a range of facial expressions, react when a familiar caregiver leaves and smile or laugh during peekaboo.
They may make repeated sounds such as "mamamama" or "bababababa" and lift their arms when they want to be picked up. These sounds do not necessarily mean they are using meaningful words yet.
Physical milestones include getting into a sitting position, sitting without support, moving objects between hands and using the fingers to rake food toward themselves. Babies may also look for objects that disappear from view or enjoy banging two objects together.
How to Encourage Development
Play peekaboo, read sturdy picture books and make time for safe floor exploration. Offer age-appropriate toys your baby can transfer between hands, bang together or reach for.
At mealtimes, carefully selected finger foods can provide opportunities to practice hand coordination when your baby is developmentally ready. Always supervise eating, seat your baby upright and avoid choking hazards.
10 Months: Exploring, Experimenting and Communicating
At ten months, some babies are finding new ways to move around their environment. They may crawl, scoot, roll to reach something or pull themselves toward furniture, although not all babies use the same movement pattern.
You might also notice purposeful gestures and increasingly elaborate babbling. A baby may stretch their arms toward you, react when you mention a familiar object or repeatedly try to retrieve something they've dropped.
Simple activities work well here. Offer a toy that can be placed inside a large container, play games that encourage turn-taking, and talk about what your baby is doing.
As mobility increases, check that furniture is secured and small objects, cords, medications and other hazards are out of reach.
11 Months: Building Confidence Through Repetition
Approaching the first birthday, your baby may become more determined to stand, explore furniture or practice picking up smaller objects. Some babies are already moving along furniture while others are concentrating on earlier movement skills.
You may hear sounds that resemble familiar words or notice gestures becoming an important part of communication. Your baby might wave after watching someone else, reach toward an object or use a particular sound to get your attention.
Repetition helps. Read the same favorite book, demonstrate putting blocks into a container or wave during everyday goodbyes.
Resist the pressure to make your baby walk before they're ready. Provide safe opportunities to move and explore without using wheeled baby walkers, which present safety hazards.
12 Months: A Year of Growth
Official CDC milestone checkpoint
By the first birthday, many babies have become much more intentional communicators and explorers. According to the CDC, the one-year checklist includes waving goodbye, calling a parent by a special name, briefly stopping when told "no" and joining simple interactive games such as pat-a-cake.
Your baby may put an object into a container and look for a toy they've seen you hide. Physical milestones include pulling up to stand, walking while holding onto furniture, picking up small items between the thumb and pointer finger, and drinking from an open cup while an adult holds it.
Does a Baby Need to Walk Independently by 12 Months?
No. Independent walking is not on the CDC's one-year milestone checklist. Walking while holding onto furniture is the listed skill.
Some babies take independent steps before their first birthday, while others do so later. The important thing is to observe overall progress and discuss any developmental concerns rather than treating the birthday as a deadline.
How to Encourage Development
Provide a safe area for exploration, read together, sing familiar songs and practice simple games. Let your child experiment with putting objects into containers and taking them back out.
At meals, allow supervised practice with developmentally appropriate foods and cups. At this age, learning is often messy, repetitive and wonderfully ordinary.
What If Your Baby Isn't Meeting a Milestone?
It can be unsettling to read a milestone checklist and notice that your baby isn't doing something listed for their age.
The first step is not to assume a diagnosis. Developmental differences can have many explanations, and one observation doesn't tell you everything about a child.
However, the CDC recommends acting early when a baby is not meeting one or more milestones, loses a skill they previously had, or when you have another concern. That means talking with your pediatrician and asking whether developmental screening or further evaluation is appropriate.
You don't need to wait until the next milestone age to raise an issue. And you don't need to wait for a concern to become severe before seeking support.
What Is Developmental Screening?
Developmental monitoring is what parents and healthcare professionals do over time: observing a child's skills, discussing changes and noticing concerns.
Developmental screening is more formal. It uses standardized, validated tools to examine development in greater detail.
The American Academy of Pediatrics recommends general developmental screening at 9, 18 and 30 months, with autism-specific screening at 18 and 24 months, as well as additional screening whenever concerns arise.
If further evaluation is recommended, early intervention services may help support a child's development. In the United States, families can contact their state's early intervention program directly to ask about an evaluation.
Developmental Milestones for Premature Babies
If your baby was born prematurely, chronological age alone may not be the best way to understand developmental expectations.
Pediatric professionals often use corrected age, also called adjusted age, which accounts for how many weeks early a baby was born.
For example, a baby born eight weeks before the expected due date who is now six months old has a corrected age of approximately four months. Their developmental progress is commonly considered using that adjusted age.
The American Academy of Pediatrics advises using corrected age to help assess developmental milestones during approximately the first two years, while continuing to consider the child's individual medical history.
Your baby's pediatrician can explain which age reference to use and whether additional monitoring or developmental services would be helpful.
Everyday Activities That Support Baby Development
Helping your baby learn doesn't require specialized toys, complicated schedules or expensive classes.
Much of early development happens during ordinary interactions.
Talk throughout the day. Describe what you're doing while preparing a feed, changing clothes or walking through a room. Your baby is learning from your voice long before they can answer with words.
Make time for supervised floor play. Safe, age-appropriate movement gives babies opportunities to develop strength, coordination and curiosity. Include tummy time while awake and closely supervised, adjusting activities as motor skills develop.
Read and sing together. Babies benefit from hearing familiar voices, rhythms and repeated words. You don't need to finish an entire book for the interaction to be worthwhile.
Respond to communication. A smile, squeal, gesture or reaching hand is an invitation to interact. Responding helps your baby learn that communication has meaning.
Let your baby explore safely. Offer simple, age-appropriate toys and sufficient space to investigate. Avoid relying on equipment that restricts movement for long stretches.
Keep the experience enjoyable. If your baby is tired, hungry or uninterested, it's fine to try again another time. Early development isn't a performance that needs constant practice.
As babies grow, their need for rest changes too. Our Baby Wake Windows by Age guide offers flexible ideas for balancing awake time, play and naps throughout the first year.
Frequently Asked Questions About Baby Milestones
Are baby milestones the same for every child?
No. Children develop at different rates, and not every skill appears in the same order or at the same time. However, official milestone checklists are useful for identifying when a concern deserves discussion or screening.
When do babies usually start smiling?
The CDC includes smiling in response to a caregiver's interaction on its two-month milestone checklist. If you aren't seeing expected social interaction or have concerns about your baby's responses, discuss them with your pediatrician.
When do babies start sitting independently?
The CDC lists leaning on the hands for sitting support at six months and sitting without support at nine months. Children may develop these abilities earlier, but those are the official checkpoint ages.
Is crawling a required milestone?
Crawling can take several forms, and the CDC's current nine- and 12-month checklists do not require a particular crawling style. If you're concerned about your baby's movement or progress, ask your pediatrician for an assessment rather than relying on crawling alone.
Should my baby be walking by their first birthday?
Not necessarily. The CDC's 12-month movement milestones include pulling to stand and walking while holding furniture, not independent walking.
When do babies begin saying words?
Babies experiment with sounds for months before using meaningful words. By one year, the CDC includes calling a parent by a special name among its language milestones. If your child isn't meeting listed communication milestones or you have concerns, talk with their pediatrician.
What if my baby develops some skills early and others later?
Different developmental areas don't always progress at the same pace. Share both strengths and concerns with your pediatrician, who can consider your child's development as a whole.
Should I wait to see if my baby catches up?
If your baby is missing a milestone, has lost a previously acquired skill, or you're worried about their development, the CDC recommends talking with a healthcare professional rather than taking a wait-and-see approach.
The Bottom Line
Your baby's first year is full of small changes that gradually become big ones. The smile that first appears during a diaper change, the toy passed from one hand to another, or the moment your baby pulls themselves upright are all parts of a much larger developmental journey.
Milestone guides can help you recognize that progress and understand when to ask questions. They shouldn't turn every new month into a test or every interaction into a lesson.
Enjoy the discoveries, make time for ordinary play and keep sharing your observations with your baby's healthcare team. If something concerns you, asking for guidance early is always appropriate.
Medical References and Further Reading
A Note From Numebaby: This article is intended for general developmental education and does not replace medical advice, developmental screening or individualized care. CDC milestones describe skills that most children can perform by specific ages, but children develop differently. Speak with your child's pediatrician whenever a milestone is missing, a previously acquired skill is lost, or you have other developmental concerns.
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