What this calculation tells you
Body mass index relates weight to height. The standard adult reference used here is for ages 20 and over. It can be one part of a health assessment, but it cannot determine your health or diagnose a condition on its own.
This tool does not measure body composition or distinguish muscle from fat. Interpretation can differ by individual context, including ethnicity, body composition and medical circumstances. It is not designed for children or pregnancy; discuss concerns with a qualified healthcare professional.
The method, explained
BMI = weight in kilograms ÷ (height in metres)^2
The inputs use the units printed beside each field. Values shown in result cards are rounded for readability; the calculator keeps more precision while applying the formula.
A worked example
Weight: 70 kg · Height: 170 cm · Age (adults 20+): 30 years.
Body mass index: 24.22
This example uses the inputs above. Your result changes when you change them.
Assumptions & limitations
- Uses the CDC standard adult categories: below 18.5, 18.5 to below 25, 25 to below 30, and 30 or above.
- Categories are reference labels, not a personal verdict or treatment recommendation.
- No health inputs are stored by the calculator code. Do not use the result to make a medical decision in isolation.
Questions about this tool
Can BMI diagnose my health?
No. It is a screening measure. A clinician may consider history, body composition and other information.
Why is this not for children?
Children and teens need age- and sex-specific interpretation rather than the adult cutoffs used here.
Context checked 30 September 2026. External sources do not endorse this tool.
Published by Sanu Tech Innovation LLP · Model notes updated 30 September 2026. Read our calculation standards or report a reproducible issue.