Enter your baby's current age and any known factors to get an evidence-based estimate of when they'll reach key developmental milestones. Based on WHO and CDC developmental data.
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Milestones have a wide range of normal. Walking, for example, is considered normal anywhere between 9 and 18 months. Only 1 in 10 children walks before 11 months, and 1 in 10 walks after 15 months — yet all are entirely within the normal range.
Child development milestones are markers tracking physical, cognitive, social, and language growth. These benchmarks are established by major health bodies like the WHO using large global cohorts. Development is sequential, with motor pathways forming from head to toe.
Behaviors or physical skills seen in infants and children as they grow and develop, categorized into motor, cognitive, and social sectors.
Premature babies need their age adjusted ('corrected age') by subtracting their weeks of prematurity from their calendar age to reflect brain growth timelines.
Milestone ranges are broad. Walking, for example, ranges normally from 9 to 18 months, with biological pacing unique to each child.
Consistent delays across multiple categories warrant pediatric evaluation to support early interventions.
Not necessarily. Some babies skip crawling entirely and go straight to standing and walking. Crawling is no longer considered a mandatory CDC milestone, though it is beneficial for motor coordination.
Statistically, girls can reach early language and fine motor milestones slightly earlier, while boys might reach certain gross motor milestones (like crawling) marginally ahead, but individual variation is huge.
Corrected age is calculated by subtracting the number of weeks the baby was born early from their chronological age. Use this corrected age to track milestones until age two.
If your baby is missing milestones at the far end of the expected range (e.g., not sitting by 9 months or not walking by 18 months), consult your pediatrician.