Baby Developmental Milestones Chart: Month by Month (0–24 Months)

No two babies hit milestones on exactly the same day. But all babies follow roughly the same sequence — and the timing windows are wider than most parent guides suggest. A 14-month-old who isn't walking is still within the normal range. A 9-month-old who isn't babbling consistently deserves attention.

This guide gives you the complete picture across all developmental domains, so you know what to watch for and when it genuinely warrants action.

How to Use This Chart

Developmental milestones describe what most babies can do by a given age. "Most" typically means 75–90% of babies — which means 10–25% of completely healthy babies haven’t hit a milestone at the listed age. For timing context on the developmental leap periods that temporarily disrupt sleep and behaviour, the Wonder Weeks offers a complementary perspective.

The ranges below reflect the typical span — the earliest most babies achieve something to the age by which nearly all typically developing babies will have done so.

Birth to 2 Months

Red flags before 2 months: Not responding to loud sounds; no eye contact; no social smile by 8 weeks; persistent floppy muscle tone.

2–4 Months

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4–6 Months

This period sees some of the most dramatic visible development. Most babies transform from passive observers to active, engaged participants.

6–9 Months

Independence begins here. Babies start to assert preferences, show stranger anxiety, and develop intentional communication.

9–12 Months

The lead-up to the first birthday. Most babies are either crawling, cruising along furniture, or taking first steps by 12 months.

Red flags at 12 months: No babbling; not pointing or waving; no words attempted; cannot sit independently; does not search for hidden objects.

12–18 Months

18–24 Months

Red flags at 24 months: Fewer than 50 words; no two-word phrases; cannot point at pictures in a book; significant loss of previously acquired skills; limited or no pretend play.

Absolute Red Flags: Act Immediately

These warrant a call or visit regardless of age — not a wait-and-see approach:

• Any loss of previously acquired skills (words, motor skills, social engagement)
• No social smiling by 3 months
• No babbling, pointing, or waving by 12 months
• No words by 16 months
• No two-word phrases by 24 months
• Consistently seeming to "look through" people rather than at them For a parent-facing deep-dive into which behaviours are true red flags and how to raise them with a paediatrician, signs of developmental delay in babies covers each domain.

Source: AAP Developmental Surveillance and Screening guidelines, Pediatrics 2020; CDC Developmental Milestones