🧠 WHO Standard · Head Growth · Free

Head Circumference Percentile Calculator

Enter your baby's head circumference, age, and sex to see their WHO percentile, z-score, and growth classification. Head circumference tracking is most critical in the first 3 years.

Head Circumference-for-Age
th percentile
Z-Score
WHO Median
Your Child
Head circumference monitoring is most critical in the first 3 years. Always discuss concerns with your pediatrician.

Why Head Circumference Matters

Head circumference reflects brain growth. In the first 3 years, a baby's brain reaches ~80% of adult size. Regular head circumference measurements can detect microcephaly (abnormally small head) or macrocephaly (abnormally large head) early, when intervention is most effective.

WHO head circumference standards are based on the same multinational study as WHO weight and height standards, ensuring consistent, high-quality reference data for children 0–5 years.

How to Measure

Remember: A single reading is a snapshot. The trend of head growth over time is what matters most.

Track head circumference over time

GrowChart automatically plots head growth on WHO percentile curves with each measurement.