BMI (Body Mass Index) is a number calculated from height and weight to estimate body fat and classify underweight, normal, overweight, or obese.
BMI = weight (kg) ÷ [height (m)]². For imperial units: BMI = (weight (lb) ÷ [height (in)]²) × 703.
Common categories: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese (≥30).
No. BMI is a quick screening tool; it does not distinguish between muscle and fat. Use other measures (waist circumference, body fat %) for deeper insight.
No. Children and teens use age- and sex-specific BMI percentiles rather than adult cutoffs.