Milestone Tracker

Each milestone carries a typical age range — the span in which most healthy children reach it. The ranges follow the WHO Motor Development Study windows for the six gross-motor milestones (sitting, standing, crawling, walking) and CDC developmental guidance for language, social, fine-motor, and thinking skills.

• The timeline draws one bar per milestone across an age axis in months. The bar spans the typical range; the dashed vertical line marks your child's current age, so anything left of the line is already due and anything right of it is still ahead.
• Status is worked out from that comparison. Upcoming means the window has not opened yet; In window means your child is inside the typical range, which is exactly where a not-yet skill is expected to appear; Past typical range means the window has closed without the milestone being marked.
• Marking a milestone records the age at which it happened. Tick the box to record it at the current age, then edit the months field if it happened earlier; the dot on the bar moves to that age.
• Age comes from the date of birth when you give one, counted in whole months; otherwise the age-in-months field is used directly.
• Storage: everything is saved in your browser with localStorage, so your progress persists between visits on this device. Nothing is uploaded.

Ranges are wide on purpose. Healthy development is not a schedule — a child who walks at 9 months and one who walks at 16 months are both squarely typical, and children often sprint ahead in one area while taking their time in another.

This tool is for general information only and is not medical advice or a developmental screening. If your child was born prematurely, milestones are usually judged against corrected age (age since the due date) for roughly the first two years. A missed window is a reason to ask, not a diagnosis; raise any concern — especially a skill your child has lost — with your pediatrician.

You can embed this util on your own site as a widget. Adding ?embed=1 to the URL loads a compact version with just the tool itself; no header, menu, or documentation. Paste this snippet into your HTML:

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