Body Mass Index (BMI)
Body mass index from height and weight with WHO classification.
About this calculator
Body mass index (BMI) is a simple anthropometric measure of weight relative to height. Formula: BMI = weight (kg) / height (m)². Introduced by Adolphe Quetelet in 1832, adopted by WHO as the standard for adult nutritional assessment (WHO Technical Report Series 854, 1995). WHO classification for adults. <16 – severe thinness. 16-16.99 – moderate thinness. 17-18.49 – mild thinness. 18.5-24.99 – normal. 25-29.99 – overweight. 30-34.99 – obesity class I. 35-39.99 – obesity class II. >=40 – obesity class III (morbid). Ethnic specifics. For Asian populations (India, China, Southeast Asia) cutoffs are lower: overweight from 23, obesity from 27.5 (WHO Expert Consultation, Lancet 2004). African-Caribbean and Hispanic populations use European cutoffs. Clinical use. Obesity and undernutrition screening in primary care. Drug dosing in obese patients (some drugs dose by ideal body weight, e.g., aminoglycosides). Surgical risk stratification. Bariatric surgery criterion (IFSO 2022 – BMI >=35 with comorbidities or >=40 without). Limitations. Does not distinguish muscle from fat – athletes with high muscle mass may falsely classify as obese, while older patients with sarcopenia may have normal BMI with hidden adiposity. Add waist circumference for visceral fat (men >=94 cm, women >=80 cm – metabolic risk). For children use age- and sex-specific percentiles (CDC growth charts).
Source
Formula version: who-2004-v1
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