These are the things most babies do, not a test. The milestones below follow the CDC’s 2022 checklists, which describe what about 75% of babies can do by that age. Babies develop at different rates. Use corrected age if your baby was born prematurely, and raise any concern with your doctor rather than waiting.
2 months
- Social: calms when spoken to or picked up; looks at your face; smiles when you talk or smile at them
- Language: makes sounds other than crying; reacts to loud sounds
- Cognitive: watches you move; looks at a toy for several seconds
- Movement: holds head up briefly during tummy time; moves both arms and legs; opens hands briefly
4 months
- Social: smiles spontaneously to get your attention; chuckles; looks at you, moves, or makes sounds to keep your attention
- Language: makes cooing sounds; turns their head toward your voice
- Cognitive: opens their mouth when hungry at the sight of breast or bottle; looks at their hands with interest
- Movement: holds head steady without support; brings hands to mouth; pushes up on elbows during tummy time
This is also when sleep changes permanently — see the 4 month sleep regression.
6 months
- Social: knows familiar people; likes looking at themselves in a mirror; laughs
- Language: takes turns making sounds with you; blows raspberries; squeals
- Cognitive: puts things in their mouth to explore; reaches for a toy they want; closes lips to show they do not want more food
- Movement: rolls from tummy to back; pushes up with straight arms on tummy; leans on hands to support themselves when sitting
9 months
- Social: shy or clingy with strangers; shows several facial expressions; reacts when you leave; smiles or laughs during peek-a-boo
- Language: makes sounds like “mamamama” and “bababa”; lifts arms to be picked up
- Cognitive: looks for objects when they drop out of sight; bangs two things together
- Movement: gets to a sitting position by themselves; sits without support; moves things from one hand to the other; rakes food toward themselves
Milestones land better on a rested baby. NapNap tracks sleep, feeds, growth and activities in one place — so when you are asked “how is she sleeping?” at the next check-up, you have an answer.
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12 months
- Social: plays games with you such as pat-a-cake
- Language: waves bye-bye; calls a parent “mama” or “dada” or another special name; understands “no”
- Cognitive: puts something in a container; looks for things they see you hide
- Movement: pulls up to stand; walks holding on to furniture (cruising); drinks from a cup without a lid with help; picks things up between thumb and finger
15 months
- Social: copies other children; shows you an object they like; claps when excited; hugs a doll or soft toy
- Language: tries to say one or two words besides “mama” or “dada”; looks at a familiar object when you name it; follows directions given with a gesture
- Cognitive: tries to use things the right way, such as a phone or cup; stacks at least two small objects
- Movement: takes a few steps on their own; uses fingers to feed themselves
18 months
- Social: moves away from you but checks you are close; points to show you something interesting; helps dress themselves
- Language: tries to say three or more words besides “mama” and “dada”; follows one-step directions without a gesture
- Cognitive: copies you doing chores; plays with toys in a simple way, such as pushing a toy car
- Movement: walks without holding on; scribbles; drinks from a cup without a lid; climbs on and off furniture without help
Most toddlers move to a single nap in this window — see nap transitions.
24 months
- Social: notices when others are hurt or upset; looks at your face to see how to react in a new situation
- Language: points to things in a book when asked; says at least two words together, such as “more milk”; points to at least two body parts
- Cognitive: holds something in one hand while using the other; tries to use switches, knobs or buttons; plays with more than one toy at the same time
- Movement: kicks a ball; runs; walks up a few stairs with or without help; eats with a spoon
When to talk to your doctor
Raise it sooner rather than later if your baby:
- Loses skills they previously had — this always warrants a prompt conversation
- Does not respond to loud sounds, or does not follow moving objects with their eyes
- Does not smile at people by around three months
- Cannot hold their head steady by around four months
- Does not babble by around nine months, or says no single words by around 15 months
- Does not make eye contact, or does not respond to their own name
- Is not walking by around 18 months
- Has a strong or persistent preference for using one hand before 12 months
None of these individually means something is wrong. All of them are reasons to ask. Early intervention works best early, and no clinician will mind being asked.
Sources
- Centers for Disease Control and Prevention, CDC’s Developmental Milestones (Learn the Signs. Act Early.), 2022 revision.
- American Academy of Pediatrics developmental surveillance guidance.
Common questions
When do babies start walking?
Most babies take their first independent steps somewhere between 9 and 15 months, and the CDC checklist places a few steps alone at 15 months. Not walking by 18 months is a reason to check in with your doctor.
Should I use my premature baby’s actual age for milestones?
Use corrected age, which is age counted from the due date rather than the birth date, generally through the first two years. A baby born ten weeks early would typically be assessed against the milestones for their corrected age.
My baby is behind on one milestone. Should I worry?
Individual variation is wide and most babies who are late on one item catch up. What matters more is the overall pattern, whether skills are being lost, and your own instinct. Any concern is worth raising with your doctor.
When do babies say their first word?
Most babies say a first real word around 12 months, often mama or dada used specifically for a parent. Babbling with consonant sounds usually starts around 6 to 9 months and is an important precursor.
What is the most important warning sign?
Losing a skill that a baby previously had. Unlike being late to reach a milestone, regression always warrants a prompt conversation with your doctor.