Calculator
Body mass index
Relates weight to height. A screening measure, not a diagnosis.
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Method and limits
| Formula | BMI = weight (kg) ÷ height (m)². Categories: under 18.5 underweight · 18.5–24.9 healthy · 25–29.9 overweight · 30+ obesity. |
|---|---|
| Who it is for | Adults aged 20 and over who are not pregnant. Children use age- and sex-specific percentiles, which this does not implement. |
| Source | CDC adult BMI categories |
| Method validated | No — not yet checked against the cited source by a person |
What this cannot tell you. BMI cannot distinguish muscle from fat, and its thresholds perform differently across ethnic groups, ages and in pregnancy. A number outside the healthy band is a reason to talk to a clinician, not a diagnosis.