Baby Milestone Explorer by Age
Enter your baby’s age and explore expected developmental milestones across movement, communication, social and cognitive development — based on NHS guidance.
Explore Milestones by Age
Select your baby’s age to see their developmental stage
⚠️ About developmental milestones
Milestones are population averages — there is significant natural variation in when children reach each one. Missing a single milestone by a few weeks is rarely a cause for concern. If you are worried about your child’s development, or if they appear to have lost skills they previously had, speak to your health visitor or GP. Do not use this tool to self-diagnose developmental delays. The NHS provides a developmental review at 6–8 weeks, 9–12 months and 2–2.5 years — attend all of these. If you have specific concerns, visit the NHS child development pages or speak to your health visitor.
Understanding Developmental Milestones
Milestones Are Averages, Not Deadlines
Developmental milestones describe what most children can do at a given age — they are not targets or deadlines. Children develop at their own pace and can be ahead in some areas while behind in others. A child who walks late may talk early. The range of normal is wide and many children reach milestones outside the typical window without any underlying issue.
Corrected Age for Premature Babies
For babies born prematurely, milestones should be assessed against their corrected age (also called adjusted age) — the age they would be if born on their due date. A baby born 8 weeks early who is now 6 months old has a corrected age of about 4 months, and their milestones should be compared to those of a 4-month-old. This correction applies until around 2 years of age.
The Four Areas of Development
Developmental milestones are typically tracked across four areas: gross motor (large movements like rolling and walking), fine motor and communication (language and speech), social and emotional development, and cognitive development (thinking, problem-solving and understanding). Progress is rarely even across all areas — this is completely normal.
When to Speak to a Professional
Contact your health visitor or GP if: your child appears to have lost a skill they previously had; they show no response to sounds, faces or voices by 3 months; they are not sitting unsupported by 9 months; they have no words by 18 months; or you have any concern about their development. NHS developmental reviews at 6–8 weeks, 9–12 months and 2–2.5 years are your most important checkpoints.
Frequently Asked Questions
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Guidance only: Milestones are based on NHS developmental guidance and represent typical averages. They are not diagnostic tools and should not be used to self-diagnose developmental delays. If you have concerns about your child’s development, always speak to your health visitor or GP. Affiliate links: Some links on this site earn us a small commission at no extra cost to you. Our recommendations are editorially independent. Read our full disclosure and disclaimer →
