Calculators
BMI Calculator
Calculate your Body Mass Index from height and weight using the WHO classification. Supports metric (cm/kg) and imperial (ft, in, lb) input, with a visual scale showing where your result falls.
About the BMI Calculator
Body Mass Index (BMI) is calculated from height and weight. The result is plotted on the WHO classification scale — underweight, normal weight, overweight or obese. The calculator works in both metric (cm/kg) and imperial (ft, in, lb).
BMI formula and categories
BMI = weight (kg) ÷ height (m)². For imperial: BMI = (weight in lb × 703) ÷ height (in)².
WHO adult categories: under 18.5 = underweight, 18.5–24.9 = normal weight, 25–29.9 = overweight, 30 and above = obese.
BMI is a screening tool, not a diagnostic measure. It doesn't distinguish muscle from fat, doesn't account for age or sex differences in fat distribution, and may misclassify athletes and older adults. Always consult a healthcare professional for health decisions.
Frequently asked questions
What are the BMI categories?
WHO adult BMI categories: under 18.5 = underweight, 18.5–24.9 = normal weight, 25–29.9 = overweight, 30 and above = obese. Some authorities use further subdivisions within the obese range.
Is BMI an accurate measure of health?
BMI is a screening tool, not a diagnostic measure. It doesn't distinguish muscle from fat, doesn't account for age or sex differences in fat distribution, and may misclassify athletes (who have high muscle mass) and older adults (who may have low muscle but high fat). Use it alongside other health measures.