The results are for information only and do not replace the advice, diagnosis or opinion of a doctor or other qualified health professional.

For reference only. Adult BMI categories follow the same WHO thresholds used by the U.S. CDC, Brazil's Ministério da Saúde, and the European Union (Eurostat/WHO). They are not a medical diagnosis. Brazil applies different Lipschitz cutoffs for adults aged 60 or older, which this calculator does not model.

How the BMI calculator works

Body Mass Index (BMI) relates your weight to your height in a single number. Health authorities such as the World Health Organization use it as a quick screening tool to see whether an adult's weight is low, healthy or high for their height. Enter your weight and height to get the BMI value, its category and a gauge that shows where you stand among all adult ranges. The calculator uses kilograms and meters in most languages, and pounds, feet and inches in the English (US) version.

BMI is your weight in kilograms divided by your height in meters squared: BMI = kg / m². In imperial units the formula is BMI = 703 × pounds / inches². The result is compared with the WHO ranges for adults: below 18.5 is underweight; 18.5 to 24.9 is normal weight; 25 to 29.9 is overweight; 30 to 34.9 is obesity class I; 35 to 39.9 is obesity class II; and 40 or more is obesity class III. Many health agencies use the same cut-offs, although some countries apply different ranges to older adults.

Example: a person who weighs 154 lb and is 5 ft 9 in (69 in) tall has a BMI of 703 × 154 / 69² ≈ 22.7, which is in the normal range. BMI is only a screening index: it does not measure body fat, muscle mass or fat distribution, so it can mislead for athletes, older adults and pregnant women, and it does not apply to children and teenagers, who need age-specific percentiles. It is not a diagnosis. Talk to a doctor or nutritionist for a full assessment.