The Short Answer
Developmental milestones are skills most babies achieve by a certain age across four domains: motor (physical movement), language and communication, social and emotional, and cognitive (thinking and problem-solving). The CDC updated its milestone guidelines in 2022 to reflect what most — not just 50% — of babies achieve by each age, making them more reliable for identifying developmental concerns.
Important: Milestones describe a typical range. All babies develop at their own pace. Talk to your paediatrician if you are concerned, rather than waiting.
2 Months
Social & Emotional
- Smiles at people (social smile)
- Calms down when spoken to or picked up
Language & Communication
- Coos, makes gurgling sounds
- Turns head towards familiar voices
Motor
- Holds head up when on tummy
- Moves both arms and legs equally
Cognitive
- Watches faces closely; follows movement with eyes
4 Months
Social & Emotional
- Smiles spontaneously, especially at people
- Enjoys play; may cry when play stops
Language & Communication
- Begins to babble ("ba," "da")
- Laughs out loud
Motor
- Holds head steady without support
- Pushes up on elbows during tummy time
- Reaches for objects; may bring hands to mouth
Cognitive
- Follows moving objects with eyes across face
- Recognises familiar people from a distance
6 Months
Social & Emotional
- Knows familiar faces; may be wary of strangers
- Likes to play with others (especially parents)
Language & Communication
- Responds to sounds by making sounds
- Strings vowels together when babbling ("ah," "eh," "oh")
Motor
- Rolls over both ways (front to back, back to front)
- Sits with support; briefly sits unsupported
- Bears weight on legs when standing (with support)
Cognitive
- Begins to pass objects between hands
- Uses hands and mouth to explore objects
9 Months
Social & Emotional
- Clings to familiar adults; shows stranger anxiety
- Has favourite toys
Language & Communication
- Babbles with consonant-vowel combinations ("mama," "dada" — not yet specific)
- Uses gestures (pointing, waving)
- Understands "no"
Motor
- Sits independently without support
- Crawls on hands and knees (or an alternative method)
- Pulls to standing; cruises along furniture
Cognitive
- Points at things; looks for hidden objects (object permanence begins)
- Bangs objects together
12 Months
Social & Emotional
- Shows affection (hugging, cuddling)
- Shows preference for certain people
- Has simple play preferences
Language & Communication
- Says "mama" and "dada" specifically for parents
- Uses one other word ("bye," "dog," "ball")
- Waves bye-bye; responds to simple requests
Motor
- Pulls to standing; walks holding on to furniture
- May take first independent steps (9–15 months is normal)
- Uses pincer grasp (thumb and index finger)
Cognitive
- Explores objects in different ways (dropping, banging, throwing)
- Finds hidden objects easily
15 Months
Social & Emotional
- Copies other children while playing
- Shows others objects to share interest
Language & Communication
- Uses 3 or more words
- Says "no" and shakes head
Motor
- Walks independently
- Climbs onto furniture with assistance
Cognitive
- Uses objects for their intended purpose (stirs with spoon, talks into phone)
- Stacks two blocks
18 Months
Social & Emotional
- Moves away from caregiver but checks back frequently
- Points to show something interesting
Language & Communication
- Uses at least 10 words
- Tries to say more words; repeats words overheard in conversation
Motor
- Walks well; may run (but falls often)
- Drinks from a cup; eats with a spoon (messily)
- Scribbles with crayons
Cognitive
- Knows what ordinary items (phone, brush, spoon) are for
- Pretend play begins (feeding a doll)
24 Months (2 Years)
Social & Emotional
- Plays alongside other children (parallel play)
- Shows increasing independence; may have tantrums
Language & Communication
- Uses 50+ words
- Combines two words together ("more juice," "daddy go")
- Points to objects or pictures when named
Motor
- Runs without falling often
- Kicks a ball; throws overhand
- Climbs on and off furniture alone
Cognitive
- Follows two-step instructions ("Pick up the toy and bring it to me")
- Sorts objects by shape and colour
When to Talk to Your Doctor
Contact your paediatrician if your child:
- Is not meeting multiple milestones in a given category at their checkup age
- Loses skills they previously had — this always requires prompt evaluation
- You have any concern about their development — trust your instincts
The CDC's Milestone Tracker App (free, iOS and Android) helps parents track progress and share it with their doctor.