Adult BMI
Metric BMI identity, US customary conversion, and WHO adult category cutoffs used as a screening ratio — not a diagnosis.
| Name | Formula | Note |
|---|---|---|
| Metric BMI |
BMI = w / h²
w in kilograms, h in meters. Result in kg/m². |
w in kilograms, h in meters. Result in kg/m². |
| US customary |
BMI = 703 × w / h²
w in pounds, h in inches. Same kg/m² scale. |
w in pounds, h in inches. Same kg/m² scale. |
| Underweight |
BMI < 18.5
WHO adult cutoff (not for children). |
WHO adult cutoff (not for children). |
| Normal range |
18.5 ≤ BMI < 25
Often labeled “healthy weight” on adult charts. |
Often labeled “healthy weight” on adult charts. |
| Overweight |
25 ≤ BMI < 30
Screening band; muscle mass can raise BMI. |
Screening band; muscle mass can raise BMI. |
| Obese (class I+) |
BMI ≥ 30
Further classes exist; this sheet stops at the 30 cutoff. |
Further classes exist; this sheet stops at the 30 cutoff. |
Related tools
Open a calculator and put these formulas to work.