Adult BMI in Metric or US Units
This calculator reports adult BMI to two decimal places and shows categories using boundaries including 18.5, 25 and 30. It is a starting point for interpreting body size, not a comprehensive health assessment.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
How to use this tool
Choose the measurement system before entering height and weight. In US mode, height means total inches: someone who is five feet eight inches tall should enter 68, not 5.8.
Results and examples
Interpret the value together with other health information. The CDC adult categories apply from age 20; children and teenagers require an age- and sex-specific growth percentile approach instead.
Worked example
A weight of 70 kg and height of 170 cm produces a BMI of approximately 24.22.
Limitations
- Pregnancy and unusually high muscle mass require separate interpretation.
- The result does not diagnose disease or prescribe weight loss.
Fields
| Field | Guidance and constraints |
|---|---|
| Units | kg and cm / lb and inches |
| Weight | Accepted range: 1–500 · Input step: 0.1 |
| Height | Accepted range: 30–300 · Input step: 0.1 |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
Should I enter feet in US mode?
No. Convert the entire height to inches first.
Can this classify a child’s BMI?
No. Children need an age-specific growth assessment rather than adult categories.
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