Calculate adult body mass index with metric or US customary measurements, view the screening category, and estimate a healthy weight range for the entered height.
Body mass index relates adult weight to height. It is a population-level screening measure, not a direct measurement of body fat and not a medical diagnosis.
BMI may be less informative for people with high muscularity, during pregnancy, for older adults, and for some populations. A clinician can interpret it alongside health history and other measurements.
BMI = weight (kg) ÷ height (m)²The conventional 703 factor is rounded. CalcRocket instead converts pounds and inches with its precise shared unit constants, then applies the metric formula; results can differ slightly from the shortcut.
BMI ≈ 703 × weight (lb) ÷ height (in)²An adult weighing 70 kg at 1.75 m has BMI = 70 ÷ 1.75² ≈ 22.86, which falls within the standard adult healthy-weight screening range.
Below 18.5
18.5 to below 25
25 to below 30
30 or higher
Body mass index, or BMI, is a screening measure that relates weight to height. It does not directly measure body fat and is not a diagnosis.
Metric BMI divides weight in kilograms by height in meters squared. US customary inputs are converted to consistent metric units before the same calculation is performed.
For adults, the commonly used healthy-weight screening range is BMI 18.5 to below 25. Individual health cannot be determined from BMI alone.
No. BMI does not directly measure body composition or fat distribution. It is a population-level screening measure with important individual limitations.
BMI cannot distinguish muscle from fat, so muscular athletes may have a higher BMI without having excess body fat.
No. These categories are intended for adults. BMI for children and teenagers must be interpreted using age- and sex-specific percentiles by a qualified healthcare professional.
The calculator applies BMI values 18.5 and 24.9 to the entered height squared. The result is an estimate, not a personal weight recommendation.
The standard adult BMI formula and category cutoffs are the same, but BMI does not capture differences in body composition, age, sex, ethnicity, pregnancy, or individual health.
CDC guidance on adult screening categories and the conventional U.S. customary shortcut.