At what age is the CDC LTSAE milestone tool used?

A simple, free checklist from babyhood through the preschool years — that is what the CDC's milestone tool is built for.

In short

The CDC "Learn the Signs. Act Early." (LTSAE) milestone checklists are designed for children from 2 months up to 5 years (60 months) of age. They are not a diagnostic test — they are a friendly, free parent-and-clinician checklist for tracking how a child plays, learns, speaks, acts and moves across that early window. There are checklists at set ages: 2, 4, 6, 9, 12, 15, 18, 24, 30, 36, 48 and 60 months.

How the LTSAE milestones work across the ages

The CDC milestone checklists give parents a clear set of "most children can do this by this age" markers, organised into social-emotional, language and communication, cognitive (learning, thinking, problem-solving), and movement and physical development. Because the early years are when development moves fastest, the checklists are spaced more closely in infancy (every two to three months) and a little wider as a child grows. The idea is gentle and ongoing — you tick what your child is already doing, celebrate progress, and notice early if a skill seems slow to arrive. The tool is meant to start conversation and prompt timely action, never to label a child.

When to seek a review

If, at any of these ages, your child has not yet reached several expected milestones — or if a skill they once had seems to fade — that is a sign to talk with a paediatrician or book a developmental review. Acting early simply means adding the right support sooner; it protects a child's confidence and momentum. A checklist that flags a concern is an invitation to look more closely, not a verdict.

The Pinnacle way

This is general information, not a diagnosis — a clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care, never from an app or checklist alone. Our clinicians use structured, clinician-administered assessment to understand the whole child, drawing on the CDC LTSAE milestones as a starting reference and building an individualised plan that may include child development support as needed.

Trusted sources

CDC "Learn the Signs. Act Early." developmental milestone guidance covering ages 2 months to 5 years; the American Academy of Pediatrics and HealthyChildren guidance on developmental surveillance and milestones.

Next step — If a milestone checklist has raised a question, or you simply want clarity on your child's development, book a developmental review with our team to map strengths and start any helpful support early.