Find your Body Mass Index in seconds — with the healthy weight range for your height.
BMI uses the WHO formula: weight (kg) ÷ height (m)². It's a rough screening tool — very muscular people can score “overweight” without excess fat. Treat it as a starting signal, not a diagnosis.
A clean BMI (Body Mass Index) calculator that works in metric or imperial units. See your BMI, the WHO category (underweight, normal, overweight, obese), the healthy weight range for your height, and how far you are from it.
Body Mass Index is a simple ratio of weight to height² that estimates whether you sit in the underweight, normal, overweight or obese range. It uses the WHO formula: BMI = weight(kg) / height(m)². Imperial input is converted to metric internally.
WHO standard ranges for adults: under 18.5 = underweight, 18.5–24.9 = normal, 25–29.9 = overweight, 30+ = obesity (Class I 30–34.9, Class II 35–39.9, Class III 40+).
BMI is a rough screening tool, not a diagnosis. It doesn't separate muscle from fat, so very muscular athletes may register as overweight. It's also less reliable for children, pregnant women, and the elderly. Treat it as a starting point — body composition, waist circumference and a doctor's view are more complete.
We invert the BMI formula at the WHO band edges: lower healthy weight = 18.5 × height(m)², upper healthy weight = 25 × height(m)² (the threshold where overweight begins). The result is shown in your selected unit.
No. Children and teens use age- and sex-specific BMI percentile charts, not the adult thresholds. Speak to a paediatrician for under-18 BMI assessment.
Estimate body-fat % from a tape measure — the U.S. Navy method, in metric or imperial.
Compare four classic ideal-weight formulas alongside the WHO healthy BMI range.
Find your Basal Metabolic Rate and daily calorie targets to maintain, lose or gain weight.