Head Circumference Percentile Calculator
Calculates head circumference-for-age percentile for infants and children using CDC or WHO growth charts to assess brain growth and detect macro/microcephaly.
Age in months
Head circumference measured at largest occipital-frontal circumference
Sex for percentile lookup
CDC recommended for US children; WHO for international
⚠️ Warnings & Contraindications
- Measurement technique is critical: measure maximum occipital-frontal circumference
- Crossing percentiles (especially downward) may be more significant than a single measurement
- WHO charts are recommended for children 0-2 years in many countries
- Familial macrocephaly is common and benign if growth trajectory is normal
ℹ️ Clinical Notes
CDC charts go up to 36 months for head circumference; WHO charts extend to 5 years. Crossing 2 major percentile lines (e.g., 50th to 10th) warrants evaluation.
References
- CDC 2000 Growth Charts - Head Circumference-for-age - CDC (2000)
- WHO Child Growth Standards - Head Circumference - WHO (2006)
Medical Disclaimer
This calculator is provided for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or calculated using this tool.
The authors and publishers of this calculator make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability, or availability of the information, products, services, or related graphics contained within this tool for any purpose.