Calculate paediatric BMI and its approximate age and sex percentile.
Adult BMI thresholds do not apply to children because body composition changes with growth, so BMI is interpreted as a percentile against an age and sex reference. This uses an approximate reference rather than the full published growth charts. A single percentile matters far less than the trajectory across several measurements, which is why growth charts plot repeated points rather than one.
BMI-for-Age Percentile
BMI = weight ÷ height²; percentile derived from an age and sex reference distribution
This reproduces a published formula for educational and reference use only. It is not a diagnostic tool, does not account for individual clinical context, and must not be used to make or change treatment decisions. Clinical assessment by a qualified healthcare professional is always required. This uses a simplified reference and is not equivalent to official WHO or CDC growth charts. Paediatric growth assessment should be carried out by a healthcare professional using the appropriate charts for your region.
BMI = weight ÷ height²; percentile derived from an age and sex reference distribution Adult BMI thresholds do not apply to children because body composition changes with growth, so BMI is interpreted as a percentile against an age and sex reference. This uses an approximate reference rather than the full published growth charts.
A single percentile matters far less than the trajectory across several measurements, which is why growth charts plot repeated points rather than one.
This calculator takes 4 inputs: Weight, Height, Age, Sex. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.