The U.S. CDC adopted the WHO adult cut-offs in 1998: underweight below 18.5, normal 18.5–24.9, overweight 25.0–29.9, obese 30 and above (with sub-classes I, II, III at 35 and 40). For children and teens age 2–19, the CDC uses the 2000 CDC growth reference cohort and interprets BMI as a percentile against same-age, same-sex peers.
What this calculator does
The calculator accepts the same inputs as the standard BMI form (age, gender, height, weight) and reports the BMI value with the CDC band:
- For adults 20+, the WHO cut-offs apply.
- For children 2–19, the band is mapped from the coarse CDC percentile thresholds (underweight, healthy, overweight, obese).
An exact CDC percentile requires the LMS lookup table, which is not embedded in this calculator. Your paediatrician can plot a child's BMI on the CDC growth chart and read off the percentile directly.
What you get beyond BMI
Beyond the BMI value and the CDC category, the calculator shows BMI Prime, Ponderal Index, body-fat percentage (Deurenberg, suppressed under 18), healthy weight range, ideal weight (Devine), lean body mass (Boer), BMR (Mifflin–St Jeor) and TDEE at five activity levels.
Next steps
- Standard BMI calculator
- Adult BMI calculator (WHO)
- Child BMI calculator (CDC percentiles)
- BMI charts and tables