Designed to make BMI understandable
BMI Calculator provides a fast way for adults to calculate Body Mass Index from height and weight in metric or US customary units. The result includes the corresponding adult BMI category and a mathematical healthy-weight reference range for the entered height.
The goal is not to turn one number into a medical conclusion. BMI is useful because it is standardized and easy to calculate, but it is only one screening measure.
How BMI is calculated
Metric
BMI is calculated by dividing weight in kilograms by height in meters squared.
US customary units
The equivalent US-unit equation uses weight in pounds and height in inches.
Healthy-weight reference range: when the calculator shows a weight range for a given height, it applies the adult healthy BMI interval of 18.5 to less than 25 to that height. It is a mathematical reference range, not a personalized treatment target.
What BMI does not measure
BMI does not directly measure body fat, muscle mass, bone density, fat distribution, fitness, blood pressure, blood glucose, cholesterol or an individual person's overall health. Two people with the same BMI can have very different body compositions and health profiles.
That is why the calculator presents BMI as a screening measure. Interpretation may need additional context such as medical history, physical examination, waist measurement, laboratory information, medications, pregnancy status, illness and other individual factors.
How health information is presented
We aim to keep the page concise, transparent and traceable to primary public-health references. Thresholds are identified as adult screening categories rather than diagnoses. The site avoids individualized treatment instructions based solely on a calculated BMI.
When a statement depends on a public-health classification, the relevant source is linked so visitors can verify the underlying guidance directly.
Primary health sources
Your BMI inputs stay in the browser
The BMI calculation itself is performed locally in your browser. Height and weight entered into the calculator are not submitted to our server as part of the calculation. The site may separately use analytics, server logs and advertising technologies as described in the Privacy Policy.
BMI Calculator provides general informational and screening information only. It does not provide medical diagnosis, treatment, emergency care or individualized medical advice and is not a substitute for evaluation by a qualified healthcare professional. This site is not affiliated with or endorsed by the CDC or the World Health Organization.