BMI Calculator

Adult BMI with WHO Standard and WHO Asian cutoffs. Child / teen BMI with WHO 2007 and CDC 2000 percentile references and an interactive growth chart.

Reviewed by Pooja V. Menon, Registered Dietitian · Last updated

Reference

WHO Asian cutoffs are recommended for adults of South/East Asian ancestry because cardiometabolic risk rises at a lower BMI than in other populations (WHO Expert Consultation, Lancet 2004).

Convert between units
Reference ranges
CategoryWHO StandardWHO Asian
Underweight< 18.5< 18.5
Normal18.5 – 24.918.5 – 22.9
Overweight25.0 – 29.923.0 – 27.4
Obese≥ 30.0≥ 27.5

Understanding BMI

BMI is a ratio of weight to height (kg / m²). For adults it’s compared against fixed cutoffs; for children and adolescents it’s compared against age-and-sex-specific percentiles because body composition changes with growth.

Why the Asian cutoff for adults?

WHO’s 2004 Expert Consultation noted higher cardiometabolic risk at lower BMI in South and East Asian populations, and recommended additional action points at 23 and 27.5 kg/m². The Indian Health Ministry and ICMR adopted these thresholds.

How the child percentile is computed

Using the Cole LMS method: z = ((BMI/M)^L − 1) / (L × S), where L, M, S come from the selected reference (WHO or CDC) at the child’s age in months, interpolated linearly between published months. The z-score maps to a standard-normal percentile and a category (thinness ≤ −2 SD, overweight > +1 SD, obesity > +2 SD per WHO guidance).

Sources

  • WHO Expert Consultation. Appropriate body-mass index for Asian populations. Lancet 2004.
  • de Onis M, et al. Development of a WHO growth reference for school-aged children and adolescents. Bull World Health Organ 2007.
  • Kuczmarski RJ, et al. 2000 CDC Growth Charts for the United States: methods and development. Vital Health Stat 2002.
  • Cole TJ. The LMS method for constructing normalized growth standards. Eur J Clin Nutr 1990.