What is BMI?
BMI is a screening number — weight divided by height squared. It does not measure body fat directly and can over- or under-state risk for very muscular or very lean people, but for most adults it's a useful first indicator of weight category.
Formula
Metric: BMI = weight (kg) / height (m)² Imperial: BMI = (weight (lb) × 703) / height (in)² WHO categories: < 18.5 Underweight 18.5-24.9 Normal 25.0-29.9 Overweight ≥ 30.0 Obese
How to use this calculator
Pick your unit system, enter height and weight, and the BMI updates live. Note: South Asians (including Indians) carry higher body fat at the same BMI than Europeans, so Indian health authorities sometimes recommend a stricter "overweight" cut-off of 23.