Baby & Child Head Circumference Percentile Calculator
Enter your child's age and head circumference to see their percentile on the official WHO Child Growth Standards reference (birth to 5 years). Head circumference is the primary screening measurement for microcephaly and macrocephaly. Calculated entirely in your browser — nothing is uploaded or stored.
Please enter a valid date of birth (child must be 0–5 years old) and head circumference.
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⚠ Educational tool, not medical advice. This calculator uses the WHO Child Growth Standards (2006). A single reading outside the typical range is not a diagnosis — pediatricians look at the full growth trajectory across multiple visits, family head size, developmental milestones, and physical exam, not one measurement in isolation. Always discuss your child's growth with a qualified pediatrician.