Adult Body Mass Index (BMI) Classification Chart
Standard adult BMI classification defined by the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) for individuals aged 20 and older.
| Classification | BMI Range (kg/m²) | Clinical Context & Health Risk |
|---|---|---|
| Severe Underweight | < 16.0 | Significantly below standard reference range. Medical consultation is recommended. |
| Moderate Underweight | 16.0 – 17.0 | Below the standard reference range. May indicate insufficient caloric or nutrient intake. |
| Mild Underweight | 17.0 – 18.5 | Slightly below standard reference range. |
| Healthy Weight | 18.5 – 25.0 | Within standard healthy adult reference range associated with lower risk of chronic metabolic conditions. |
| Overweight | 25.0 – 30.0 | Above standard reference range. Muscular individuals may also fall here due to lean muscle mass. |
| Obesity Class I | 30.0 – 35.0 | Class 1 obesity. Associated with elevated risks for cardiovascular and metabolic conditions. |
| Obesity Class II | 35.0 – 40.0 | Class 2 obesity. Clinical lifestyle and health screening is strongly advised. |
| Obesity Class III | 40.0+ | Class 3 (severe) obesity. Requires comprehensive clinical and metabolic guidance. |
Clinical Screening Reference & Medical Notice
Calculations provided on HOW WEIGHT are based on published statistical standards (such as WHO, CDC, and peer-reviewed metabolic equations) and are intended for educational and general screening purposes only.
They do not directly measure body fat distribution or visceral adipose tissue, nor do they replace personalized clinical diagnostic evaluation by a licensed healthcare provider. Learn more about our clinical methodology & disclaimers →