BMI Calculator for Children

Inputs

219
8150
70210

Result

BMI
17.9
Healthy
Healthy weight (5–84th)
  • Age10 years (boy)
  • Approx. healthy rangeBMI 15.4 – 19.4
  • Approx. overweight cutoff (85th %ile)BMI 19.4Borderline
  • Approx. obesity cutoff (95th %ile)BMI 22.2High risk
  • NoteInterpolated; not a substitute for CDC chart lookupPediatric — see doctor for actual percentile

How to use this calculator

  • Use the child's most recent measured weight and height.
  • Pick the right sex — pediatric BMI cutoffs differ by sex.
  • A "warning" or "error" badge means see a pediatrician — don't panic; growth varies.
  • For children under 2, this tool doesn't apply. Weight-for-length is used instead.

About this tool

BMI for children is interpreted differently than for adults — the same number means different things at different ages because kids' body composition changes through growth. Pediatricians use age- and sex-specific percentile charts (CDC in the US, WHO globally) instead of fixed BMI cutoffs. This calculator gives an approximate categorisation by interpolating the 85th and 95th-percentile cutoff curves, which is good enough to know whether a doctor visit is warranted — but not a substitute for an actual percentile lookup at a check-up. For ages under 2, BMI isn't used at all; doctors track weight-for-length instead.

Frequently asked

BMI doesn't distinguish muscle from fat. Athletic kids (especially young teens with broad builds) often score "overweight" by BMI. A pediatrician can do a skinfold check or just eyeball it.

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