CDC Child BMI Calculator

For children and teens aged 2 to 19. All calculations run locally in your browser.

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Under CDC standards, BMI for children and teens is assessed using age- and sex-specific percentiles, not fixed cutoffs. Please consult a pediatrician or refer to the official CDC growth charts. This tool is for preliminary screening only and is not a medical diagnosis.

100% client-side. Your child's data never leaves this browser.

About Child BMI

Body Mass Index (BMI) for children and teens is calculated from height and weight, but it is interpreted differently than adult BMI. Because body composition changes rapidly during growth, a child's BMI must be compared with age- and sex-specific growth charts. The CDC uses percentiles: the same BMI can be healthy at one age and concerning at another. A fixed cutoff such as 18.5 or 25 does not apply to children, which is why percentile assessment matters and why a pediatrician should be consulted.

Calculating BMI locally in your browser is safer for children's health data. Unlike server-based tools that may log or store sensitive measurements, this calculator runs 100% client-side, so height, weight, age, and sex never leave your device. Nothing is uploaded, stored, or shared.