How this tracker works
Enter your child's date of birth (age is calculated automatically) or their age in months directly. The tracker highlights the nearest developmental checkpoint your child has reached in the milestone table below, across four domains: Social/Emotional, Language/Communication, Cognitive, and Movement/Physical.
These checkpoints and milestones follow the CDC's "Learn the Signs. Act Early." developmental surveillance ages — the ages by which most children (about 75%) are expected to reach each milestone, not a strict pass/fail test.
Milestones by age (birth – 5 years)
| Age | Social / Emotional | Language / Communication | Cognitive | Movement / Physical |
|---|---|---|---|---|
| 2 mo | Calms when spoken to or picked up; looks at your face | Makes sounds other than crying; reacts to loud sounds | Watches you as you move; looks at a toy for several seconds | Holds head up during tummy time; moves both arms and legs |
| 4 mo | Smiles on their own to get your attention; chuckles | Makes sounds back and forth with you; makes different sounds to express feelings | Reaches for a toy; opens hands briefly | Holds head steady without support when held; holds a toy placed in hand |
| 6 mo | Knows familiar people; likes to look at self in a mirror | Takes turns making sounds; blows "raspberries" | Puts things in mouth to explore; reaches to grab a toy | Rolls from tummy to back; pushes up with straight arms on tummy |
| 9 mo | Shy or clingy with strangers; has favourite toys | Understands "no"; makes different sounds ("mamama", "bababa") | Looks for objects when dropped; plays peek-a-boo | Sits without support; pulls to stand; moves objects between hands |
| 12 mo | Plays games like pat-a-cake; waves bye-bye | Says "mama"/"dada" and one other word; tries to repeat words you say | Puts something in a container; looks for things they see hidden | Pulls to stand, "cruises" along furniture; may take a few independent steps |
| 15 mo | Copies other children while playing; shows you objects they like | Tries to say 3+ words besides mama/dada; follows 1-step directions without gestures | Tries to use things correctly (cup, phone); stacks 2+ small objects | Takes a few steps on their own; uses fingers to feed themselves |
| 18 mo | Moves away but glances back to check you're near; points to show you something interesting | Says several single words; points to a body part when named | Copies you doing chores; plays with toys simply (rolls a car) | Walks without holding on; scribbles; drinks from a cup without a lid |
| 2 yr | Notices when others are hurt or upset; looks at your face to see how to react | Points to things in a book; says 2+ words together ("more milk") | Holds something in one hand while using the other; uses switches/buttons on a toy | Kicks a ball; runs; walks up stairs holding on |
| 30 mo | Plays next to other children; shows independence (says "no" often) | Says about 50 words; says two or more words together | Uses things to pretend play; follows two-step instructions | Uses hands to twist things (knobs, lids); jumps with both feet off the ground |
| 3 yr | Notices other children and joins them to play; shows concern for a crying friend | Talks with you in conversation of 2+ back-and-forth exchanges; says first name, age, sex | Draws a circle when shown how; avoids touching a hot object | Strings items together; puts on some clothes independently; uses a fork |
| 4 yr | Pretends to be something else during play; asks to play with other children | Says sentences with 4+ words; says some words from a song, poem, or story | Names a few colours; tries to solve problems from one point of view | Catches a large ball most of the time; hops on one foot |
| 5 yr | Follows rules or takes turns in games; sings, dances, or acts for you | Tells a story with 2+ events; answers simple "why" questions | Counts to 10; uses time words correctly (yesterday, tomorrow) | Buttons some buttons; hops, skips, may somersault; uses a fork and spoon, sometimes a table knife |
Clinical use
- Surveillance tool, not a diagnostic test: these are population-level ages by which most children reach a milestone — a child who hasn't reached one yet isn't automatically abnormal, but consistently missing multiple milestones across checkpoints, or losing a skill they'd already gained, warrants developmental assessment.
- Corrected age for prematurity: for babies born preterm, milestones are usually tracked against their corrected age (age from the due date, not the birth date) until around 2 years.
- Standard well-child visit ages: these checkpoints align with typical paediatric surveillance visits, which is why milestone checklists (like the CDC's) are built around them.
- When to seek assessment: loss of previously acquired skills at any age, no words by 16 months, not walking by 18 months, or no eye contact/social smiling by the expected ages are all reasons for earlier evaluation rather than waiting for the next checkpoint.
Frequently asked questions
What are developmental milestones?
They're skills most children develop by a certain age, across four domains: social/emotional, language/communication, cognitive (thinking, learning, problem-solving), and movement/physical development.
What if my child hasn't reached a milestone yet?
These ages represent when most children (about 75%) reach a milestone, not a strict cutoff — some variation is normal. That said, consistently missing several milestones, or missing a milestone by a wide margin, is worth discussing with your paediatrician rather than assuming it will resolve on its own.
Should premature babies be tracked differently?
Yes — for babies born significantly preterm, milestones are usually assessed against their "corrected age" (their age counting from the original due date, not the actual birth date) for roughly the first two years, since their development naturally follows the corrected timeline more closely.
What's a red flag that needs earlier evaluation?
Losing a skill the child previously had (at any age), no words by around 16 months, not walking independently by 18 months, and no social smiling or eye contact by the expected early checkpoints are all reasons to seek assessment sooner rather than waiting for the next routine visit.
How often should development be checked?
Development is typically reviewed at every well-child visit, which is why standard milestone checklists (like this one) are built around common visit ages — 2, 4, 6, 9, 12, 15, 18, 24, 30, 36, 48, and 60 months.
Do these milestones apply to every child equally?
They're population averages, and individual variation is normal and expected. They are not adjusted for specific medical conditions, and a child with a known diagnosis affecting development should be tracked against guidance specific to that condition alongside these general milestones.
References
- Centers for Disease Control and Prevention (CDC) & American Academy of Pediatrics (AAP). "Learn the Signs. Act Early." developmental milestone checklists, 2022 revision.
- American Academy of Pediatrics. Recommendations for Preventive Paediatric Health Care (Bright Futures/AAP periodicity schedule).