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Your baby month by month

What most children do at each age, in the CDC's own words, and something to play, say and read every month.

The CDC's “Learn the Signs. Act Early.” checklists list what most children (75% or more) can do by 2, 4, 6, 9, 12, 15, 18, 24 and 30 months, and by 3, 4 and 5 years. Pick your child's age below. Checklist ages show the CDC's milestones word for word, and every month has its own play, talk and reading ideas.

Checked October 29, 2026.

What the CDC's milestones mean

Developmental milestones are things most children (75% or more) can do by a certain age. The CDC and the American Academy of Pediatrics revised the checklists in 2022. In the CDC's words:

Milestones were placed at ages by which at least 75% of children would be expected to exhibit them, in an effort to make even one missing milestone more "actionable" (likely to prompt screening and possible referral). With a milestone at 50%, half of all children would still reasonably be expected to have not yet achieved it. This change is intended to reduce the "wait and see" approach often taken when a child is missing an average age milestone.

So a milestone on the list is something most children do by that age, and many do it sooner. The checklists don't list everything: crawling isn't on any of them. And they aren't a test. The CDC says its milestones “should not be used as screening or diagnostic tools to detect developmental delays.” That's what your pediatrician's developmental screening is for.

If you're worried

The CDC's advice is “Don't wait.” If your child isn't doing one or more things on the checklist for their age, has lost a skill, or you have any other concern, talk with your child's doctor and ask about developmental screening. Every month page has the CDC's next steps, including how to reach your state's early intervention program.

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