About the Baby Milestones Checker
This baby milestones checker works out your child’s age and lists the developmental milestones for the most recent CDC checkpoint they have reached — 2, 4, 6, 9, 12, 15, 18, 24 or 30 months, or 3 years. Milestones are grouped the way the CDC groups them: social and emotional, language and communication, cognitive (learning and problem-solving) and movement or physical development. It also tells you when the next checkpoint arrives.
The lists come from the CDC’s “Learn the Signs. Act Early.” program, revised with the American Academy of Pediatrics in 2022. Each milestone is something at least 75% of children can do by that age, so a child who has not reached one yet is in the minority — a reason to talk with your pediatrician, not a diagnosis. For babies born prematurely, enter how many weeks early they were and the checker uses corrected age, as pediatricians usually do until about age 2.
Use it before well-child visits, to know what to watch for and play with next, or to put a worry into context. If your child is missing milestones, or loses skills they once had, the CDC advises acting early: talk to your child’s doctor and ask about a developmental screening. Do not wait to see — early support makes a real difference.
How to use the baby milestones checker
- 1Enter your child’s date of birth and the date you are checking (usually today).
- 2If your baby was born before 37 weeks, enter how many weeks early they were.
- 3Read the milestone list for the checkpoint your child has reached.
- 4Note the next checkpoint date and what to look forward to.
- 5Talk to your doctor about any milestone your child has not reached.
Formula and method
Age is counted in completed calendar months from the birth date. For a premature baby, the birth date is first moved forward by the number of weeks born early, which gives corrected (adjusted) age — the age a baby would be if born on the due date. The checker then picks the most recent CDC checkpoint the child has reached and lists its milestones; babies under 2 months see the 2-month list as “coming up”.
The milestones are those published by the CDC’s Learn the Signs. Act Early. program after its 2022 revision with the AAP, which set each milestone at the age by which at least 75% of children achieve it. That is a higher bar than older checklists that used the 50% (average) age, so missing one is a meaningful signal to discuss with a doctor rather than something to wait out.
- Weeks early
- 40 weeks minus gestational age at birth
- Checkpoint
- CDC milestone age the child has most recently reached
Worked examples
Baby born March 15, 2026, checked September 29
At 6 months 14 days the most recent CDC checkpoint is 6 months, which lists 12 milestones such as rolling from tummy to back, laughing and blowing raspberries. The next checkpoint, 9 months, falls on December 15, 2026.
Premature baby born 8 weeks early
Moving the birth date forward 8 weeks (56 days) gives a corrected birth date of May 10, 2026, so the baby’s corrected age is 4 months 19 days. The 4-month milestones apply, and the 6-month checkpoint falls on November 10.
Looking ahead to the 1-year milestones
Choosing the 1-year checkpoint shows the 10 CDC milestones for that age, including waving bye-bye, calling a parent “mama” or “dada”, pulling up to stand and using a pincer grasp.
Newborn under 2 months
A 4-week-old has not reached the first CDC checkpoint yet, so the 2-month list of 11 milestones — like smiling back and holding the head up on the tummy — is shown as coming up on November 1.
Frequently asked questions
What are the CDC developmental milestones?+
They are skills that at least 75% of children show by a given age, grouped into social/emotional, language/communication, cognitive and movement/physical areas. The CDC and AAP revised them in 2022 for checkpoints from 2 months to 5 years.
Should I worry if my baby misses a milestone?+
Because CDC milestones are set at the 75% mark, missing one means your child is behind most peers. It is not a diagnosis, but it is a good reason to talk to your pediatrician and ask about a developmental screening.
Should I use corrected age for a premature baby?+
Yes. For babies born before 37 weeks, pediatricians usually judge milestones by corrected age (counted from the due date) until about age 2. Enter how many weeks early your baby was to apply it.
Why is crawling not on the CDC milestone checklists?+
Crawling does not appear on the 2022 checklists. Many typically developing children skip crawling or move in other ways, such as bottom-shuffling, before pulling up and walking, so it does not work as a milestone most children reach by a set age.
When are developmental screenings done?+
The AAP recommends general developmental screening at the 9-, 18- and 30-month well-child visits, and autism screening at 18 and 24 months, in addition to milestone checks at every visit.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.