What are the CDC milestones?

Skills most children (75%) can do by a certain age, grouped into social and emotional, language, cognitive and movement areas, with checklists from 2 months to 5 years.

Is my baby behind if they miss a milestone?

Not necessarily, because a quarter of children may not show a skill yet. But the CDC advises talking to your doctor rather than waiting.

Should I use corrected age for milestones?

Yes, for babies born before 37 weeks, until about age 2, unless your pediatrician advises otherwise.

When are developmental screenings done?

The AAP recommends general developmental screening at 9, 18 and 30 months and autism screening at 18 and 24 months.

Does this tool diagnose anything?

No. It's a checklist to help you notice and discuss development with your pediatrician.

Baby Milestone Checker (CDC, 2-12 Months) / Tot

Medically reviewed by Safi Ullah Khan · Written by Muneeb Rana · Last updated 21 October 2026

Quick answer: A baby milestone checker walks you through the CDC's checklists of skills most babies (75%) show by 2, 4, 6, 9 and 12 months, in social, language, thinking and movement areas. Tick what your baby does. Missing one or more milestones, or losing skills, is a reason to talk to your pediatrician and act early.

TL;DR

Uses CDC 'Learn the Signs. Act Early.' checklists (revised with the AAP).
Use corrected age for babies born before 37 weeks.
It's a conversation starter, not a screening test.

This baby milestone checker turns the CDC's milestone checklists into a simple tick list for your baby's age. The CDC lists skills that 75% of children show by each age, so a missed item means 'talk to your doctor', not 'something is wrong'.

How to use the baby milestone checker

Enter your baby's age, or birth date (and weeks of gestation if born early).
The checker opens the nearest CDC checklist: 2, 4, 6, 9 or 12 months.
Tick each skill you've seen your baby do.
Read the summary and, if anything is unticked, the suggested next step.
Save or print the list to take to your next checkup.

How the baby milestone checker works

The checklist content mirrors the CDC's milestone lists. Examples:

Age	Social / emotional	Language	Movement
2 months	Smiles when you talk to them	Makes sounds other than crying	Holds head up on tummy
4 months	Smiles to get your attention	Coos, makes sounds back	Holds head steady when held
6 months	Laughs	Blows raspberries, squeals	Rolls tummy to back
9 months	Shy or clingy with strangers	Babbles 'mamama', 'bababa'	Sits without support
12 months	Plays pat-a-cake	Waves bye-bye, says 'mama'/'dada'	Pulls to stand, cruises

The AAP recommends developmental screening with validated tools at 9, 18 and 30 months, and autism screening at 18 and 24 months, according to the CDC.

Worked example

Ibrahim is 9 months old. His parents tick 'sits without support', 'babbles bababa' and 'looks when you call his name', but not 'lifts arms to be picked up'. The checker suggests raising it at his 9-month visit, where the pediatrician does a formal developmental screen anyway.

If your baby misses a milestone

The CDC says: don't wait. If your baby isn't meeting one or more milestones, has lost skills they once had, or you have other concerns, talk to your pediatrician and ask about developmental screening. In the US you can also contact your state's early intervention program directly; in the UK, your health visitor.

Month-by-month guides

For what to expect between checklists, see baby development month by month, for example the 6-month-old development page. Preemies: use the corrected age calculator.

Keep notes for checkups

Write down when you first noticed a skill. Tot's log keeps feeds, sleep and growth together with your notes, so checkups start with facts. See the newborn checkup schedule.

Download Tot free on the App Store or Google Play. Free with ads; optional Premium.

Sources

CDC: Developmental Milestones (Learn the Signs. Act Early.): www.cdc.gov (accessed 21 October 2026)
AAP HealthyChildren.org: Developmental Milestones, 1 Month: www.healthychildren.org (accessed 21 October 2026)
AAP HealthyChildren.org: Corrected Age for Preemies: www.healthychildren.org (accessed 21 October 2026)

Medical disclaimer:

Tot and this website give general information only. Feeding, sleep and growth ranges vary; always follow your pediatrician's advice. If your baby is unwell, contact your doctor or emergency services.

Baby Milestone Checker