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How to read a child's BMI
Children and teenagers are still growing, so a single BMI number means little on its own. Instead, BMI is compared with thousands of children of the same age and sex and expressed as a percentile. For example, the 75th percentile means the child's BMI is higher than 75% of children of that age and sex.
CDC weight-status categories (ages 2–20):
• Underweight — below the 5th percentile
• Healthy weight — 5th to below the 85th percentile
• Overweight — 85th to below the 95th percentile
• Obesity — 95th percentile or above
This calculator uses the U.S. CDC BMI-for-age growth reference (the standard used by the CDC's own child BMI tool). It is a screening aid, not a medical diagnosis — growth and puberty affect these numbers. For adults (20+), use the adult BMI calculator on our homepage. Always consult a qualified paediatrician for advice about your child's health.
Need in-home paediatric nursing or care support from our qualified care team? See our home-healthcare services or talk to our team.