7 Milestones to Expect in Your Baby's First Year

Your baby's first year is filled with incredible changes. From that first social smile to those wobbly first steps, each milestone marks a significant leap in your child's development. As a parent, understanding what to expect can help you celebrate achievements, support your baby's growth, and know when to seek guidance. For a broader view of what comes next, see our complete guide to child development from birth to 18.

Understanding Developmental Milestones

Developmental milestones are behaviors or physical skills that most children demonstrate by a certain age. They fall into four main categories:

• Motor skills - Physical movements and coordination
• Language and communication - Sounds, words, and understanding
• Cognitive development - Thinking and problem-solving
• Social-emotional growth - Relationships and feelings

One number decides how you should read every list that follows. Each CDC checklist opens with the same sentence: "Developmental milestones are things most children (75% or more) can do by a certain age." That threshold was a deliberate choice, and the 2022 revision of these checklists spells out why the older median-age lists were dropped: a list built on the 50% mark "might encourage a wait-and-see approach because half of children are not expected to achieve the milestone by that age."

Hold all of it loosely. Treat what follows as typical ranges, not deadlines. Most babies arrive early at one skill and late at another, and the same child often does both in the same month.

Appetite moves the same way. A stretch of near-constant feeding usually sits beside one of these jumps rather than signalling a problem — the pattern has a name and a normal range, set out in our piece on cluster feeding and contact naps.

Formal screening runs on its own schedule. Under American Academy of Pediatrics guidance that means general developmental screening at the 9-, 18- and 30-month visits, and autism screening at 18 and 24 months — or any time a parent or a doctor has a concern. A checklist and a screening tool are not the same instrument, and the CDC says so plainly: milestone checklists "are not a substitute for standardized, validated developmental screening tools." One starts the conversation. The other answers it.

Milestone 1: The Social Smile (Around 2 Months)

One of the most heartwarming moments for new parents is seeing their baby's first genuine social smile. Around six to eight weeks of age, most babies begin smiling in response to your voice, face, or gentle touch.

This isn't just a reflex. It is your baby's first real social interaction, and a sign that their brain is making important connections.

What You'll Notice:

• Your baby looks at your face and smiles when you talk to them
• They may coo or make sounds while smiling
• Smiles appear most often during face-to-face interaction
• Your baby tries to maintain eye contact

Encouraging it costs nothing. Spend the alert stretches face to face, talk and sing, overdo the expressions, and answer every smile you get. That back-and-forth is the whole lesson: something happens when I do this.

Milestone 2: Head Control and Tummy Time Success (2-4 Months)

Your baby's journey toward physical independence begins with head control. During the first few months, your baby gradually builds the neck and upper body strength needed to hold their head steady.

By around four months, most babies can:

• Hold their head up without support when held upright
• Lift their head and chest during tummy time
• Turn their head to follow objects or sounds
• Show less head bobbing when sitting with support

Tips for Successful Tummy Time:

• Start with 3-5 minute sessions, two or three times a day
• Place colorful toys within your baby's line of sight
• Get down on the floor at your baby's level
• Try tummy time on your chest while you recline
• Gradually increase duration as your baby gets stronger

For creative ways to make tummy time engaging, see our guide on tummy time activities for newborns.

Milestone 3: Rolling Over (4-6 Months)

Rolling over represents a major step in your baby's physical development. Tummy to back almost always comes first, since that direction needs less coordination; back to tummy usually follows weeks later. On the CDC's six-month checklist you will find "rolls from tummy to back," which puts three in four babies there by then. Plenty roll at four months. Plenty do not, and are fine.

Supporting This Milestone:

• Continue regular tummy time to build core strength
• Place interesting toys just out of reach to encourage movement
• Let your baby practice on a safe, flat surface
• Avoid keeping your baby in containers like swings or bouncers for extended periods

Milestone 4: Sitting Independently (Around 6 Months)

Sitting without support opens up a whole new world for your baby. In that WHO study, half the children were sitting unsupported by 5.9 months, and the full normal window ran from 3.8 to 9.2 months. Six months sits in the middle of a five-month spread, not at the front of it.

Before achieving full independence, many babies go through a "tripod sitting" phase, stabilizing their torso with both arms propped between their legs.

Why Sitting Matters:

Independent sitting frees your baby's hands for exploration and play. This position also gives them a better view of their environment, which supports cognitive development. It's also when many families begin baby-led weaning, since sitting upright is a key readiness sign for self-feeding. Try our infant cognitive development games to support this growth.

Supporting it is mostly floor work. Practice supported sitting in your lap or inside a ring of pillows, keep the interesting toys at eye level so staying upright pays off, and go easy on seats that hold your baby up for them — the muscles only get stronger when they are the ones doing the holding.

Milestone 5: Babbling and First Sounds (6-9 Months)

Language development accelerates during the second half of your baby's first year. Between six and nine months, most babies begin babbling—stringing together consonant and vowel sounds like "ba-ba" or "da-da."

What it looks like:

• Repeated syllables like "ma-ma," "da-da," or "ba-ba"
• Your baby experiments with different sounds and pitches
• They may "talk" to toys or their reflection
• Babbling often increases during social interaction
• Your baby responds to their name by looking at you

How to Encourage Language Development:

• Talk to your baby throughout the day, describing what you're doing
• Read board books together, pointing to pictures
• Respond to your baby's babbles as if having a conversation
• Sing songs and nursery rhymes
• Limit background noise during interaction time

For more specific activities, explore our infant language development activities guide. Long before babble becomes words, crying carries most of your baby's early communication — our guide to reading your baby's different cries covers what patterns are real and what's marketing.

Milestone 6: Crawling and Mobility (7-10 Months)

Crawling represents your baby's first form of independent mobility. While the classic hands-and-knees crawl is most common, babies get creative—some scoot on their bottoms, army crawl on their bellies, or roll to get where they want to go.

Why Crawling Matters:

Crawling builds strength, coordination, and spatial awareness. It also hands your baby the independence to go and find out what is behind the sofa, which does more for thinking skills than any toy marketed for it.

Milestone 7: Pulling to Stand and First Steps (9-12 Months)

The final major milestone of the first year is the transition to upright mobility. WHO put the median at 7.4 months for standing with support and 12 months for walking alone, with everything from 8.2 to 17.6 months counted as normal for those first solo steps. A nine-month walker and a seventeen-month walker both sit inside that band.

Signs you'll spot:

• Your baby pulls up on furniture, your legs, or anything within reach
• They "cruise" along furniture while holding on
• Standing becomes steadier over time
• First steps are often wobbly and followed by sitting down quickly
• Your baby may prefer crawling for a while even after learning to walk

When to Talk to Your Pediatrician

While every baby develops differently, certain signs warrant a conversation with your healthcare provider. CDC's instruction is two words long: "Don't wait." If your baby is missing one or more milestones, has lost a skill they once had, or something simply feels off to you, that is reason enough to raise it at the next visit — or before it. The 2022 revision went as far as deleting the old separate list of "warning signs," on the reasoning that missing a milestone most children reach already earns the same follow-up.

Every state and territory runs an early intervention program, free or reduced-cost for any child who qualifies, and the CDC's own summary is that these services "can have a significant impact on a child's ability to learn new skills and overcome challenges." One detail parents are rarely told: a doctor's referral is not required. You can call your state's program yourself and ask for an evaluation.

Track Your Baby's Progress

Keeping track of your baby's milestones helps you celebrate achievements and notice any areas that might need attention. Our Milestone Tracker tool makes it easy to log your baby's progress and see how their development unfolds over time.

There is a free Milestone Tracker app from the CDC as well, covering ages two months to five years in English and Spanish. Whichever tool you use, the point is the same: walking into an appointment with specific observations beats trying to remember them in the room.

Key Takeaways

• Milestones are guidelines, not deadlines. Every baby develops at their own pace. The ages mentioned represent when most babies (75%+) reach certain skills, but individual variation is normal.
• The four areas of development are interconnected. Motor skills, language, cognitive abilities, and social-emotional growth all influence each other.
• Responsive parenting matters. Your everyday interactions are more powerful than any toy or program.
• Tummy time and floor play earn their place. More time in active positions is associated with stronger gross motor development — the evidence behind it is mostly observational, but it points one way.
• Trust your instincts. You know your baby best. If something concerns you, bring it up with your pediatrician.

Medical Disclaimer: This article is for informational purposes only and is not a substitute for medical advice. Milestone windows describe groups of babies, not your baby. Bring anything that worries you — a skill that disappeared, a checklist item your baby has not reached, or a feeling you cannot quite name — to your pediatrician rather than waiting for the next scheduled visit.

Frequently Asked Questions

What if my baby skips a milestone like crawling?

Skipping milestones like crawling is more common than many parents realize. Some babies move directly from sitting to pulling up and walking. What matters most is that your baby is making progress in their mobility and showing curiosity about their environment.

How much tummy time does my baby need each day?

AAP guidance is more modest than it sounds: two to three sessions a day of 3 to 5 minutes, starting the day you bring your baby home, working up to 15 to 30 minutes a day by seven weeks. Spread out, that is a few minutes on the floor after each diaper change.

Should I be concerned if my baby isn't walking by their first birthday?

Walking by twelve months is average, but the normal range extends from 8 to 18 months. Many healthy babies don't take their first steps until 13-15 months. If your baby isn't walking by 18 months, or isn't pulling to stand by 12 months, discuss this with your pediatrician. If the comparison pressure is getting to you, our piece on why you shouldn't rush your baby to milestones explains the research behind these wide windows and the hidden cost of rushing.

Do premature babies reach milestones later?

Yes, premature babies often reach milestones later when measured by their birth date. Pediatricians use "corrected age" instead — your baby's age in weeks minus the number of weeks they arrived early — until about two years, by which point most children have caught up to the typical milestone range.

How can I tell the difference between normal variation and a developmental delay?

Normal variation means your baby is still making progress, just on their own timeline. A potential delay might show as: missing multiple milestones, losing skills they previously had, extreme muscle stiffness or floppiness, or little interest in interacting with people.

Track your baby's developmental journey with our free Milestone Tracker tool.