Kids BMI: why it’s different from adult BMI
For children and teenagers, BMI is interpreted using BMI‑for‑age percentiles, because body composition changes as kids grow.
Adult BMI cutoffs (like “25 is overweight”) should not be applied to kids.
Quick kids BMI calculator
What is a BMI percentile?
A BMI percentile compares a child’s BMI to a reference population of the same age and sex.
Percentiles are screening tools—not diagnoses—and they must be interpreted in context (growth history, puberty timing, activity, and medical factors).
Common takeaways (general screening language)
Guidelines vary, but many references describe:
- lower percentiles: potentially underweight
- middle percentiles: generally typical range
- higher percentiles: potentially higher risk
If you’re concerned about growth or weight changes, talk with a pediatric clinician.
Helpful companion tools (for families)
For general health tracking, these can add context:
- Waist-to-height ratio (WHtR) (measurements, not a diagnosis)
- Measurement tracker