BMI for Kids Calculator
Children and teens are not judged by adult BMI cutoffs. Enter the age, sex, height and weight of the child (2 to 20 years) to get the BMI percentile and weight category.
Sex
BMI
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Percentile
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Category
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The marker shows where this child sits on the percentile scale: below the 5th is underweight, 5th to 85th is healthy, 85th to 95th is overweight, 95th and above is obesity.
General information only, not medical advice. If you are worried about a child’s growth, please see a doctor.
How to use
- Enter the child’s age in years plus any extra months (for example 8 years and 6 months).
- Choose boy or girl, then enter height in cm and weight in kg.
- The BMI, percentile estimate and weight category appear instantly, along with a short explanation.
How the estimate works
A child’s BMI is compared with CDC-style reference values for the same age and sex using the LMS method, then converted to a percentile. This is a simplified estimate of the official growth charts, good for general awareness but not a medical diagnosis.