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Adult BMI charts are not appropriate for children. Child BMI must be interpreted against age and sex-specific reference charts that account for normal growth patterns.
The Formula
BMI = Weight ÷ Height² (same formula) | But use age-sex percentile charts for interpretation
Standard formula used by professionals worldwide
Worked Example
Step-by-step
Child BMI 22 at age 12 may be healthy. Same BMI at age 6 would indicate obesity.
Key Points
- Accuracy: Results are as accurate as the inputs you provide
- Units: Always use consistent units throughout your calculation
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Frequently Asked Questions
What percentile is healthy for children?
5th to 85th percentile is healthy weight. Above 95th percentile is obese.
When does adult BMI apply?
From age 18 (some guidelines use 20). Before this use paediatric growth charts.
Should overweight children diet?
Only under medical supervision. The goal is usually to maintain weight while growing taller.
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