BMI Calculator
Calculate body mass index from metric or imperial input, with WHO categories and healthy range.
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Healthy weight range
WHO: <18.5 / 18.5-24.9 / 25-29.9 / ≥30
How to use it
- Choose metric (centimeters and kilograms) or imperial (feet plus inches and pounds).
- Enter your height and weight; the extra inches field is optional.
- Your BMI appears to one decimal place with a colored WHO category: underweight, normal, overweight or obese.
- The healthy weight range for your height (BMI 18.5 to 24.9) is shown in your chosen units.
- Use Clear to reset all fields.
Common use cases
- Fitness tracking - watch the number move as training and diet change over weeks.
- Health checkups - reproduce the same figure your doctor or nurse calculated.
- Goal setting - read the healthy weight range as a rough personal target band.
- Forms and applications - fill in a BMI value required by a paper or online form.
Why it stays private
The formula is one division done in your browser. Your height and weight are never sent anywhere, never stored, and the page makes no network requests after it loads.
FAQ
Q: Is BMI accurate for athletes? A: Not always. BMI does not distinguish muscle from fat, so very muscular people can read as overweight. Treat it as one signal among several, not a diagnosis.
Q: Do the categories differ by country? A: This tool uses the WHO adult thresholds: under 18.5, 18.5 to 24.9, 25 to 29.9, and 30 or above. Some national guidelines use adjusted cutoffs for specific populations.
Q: Is it suitable for children? A: No. Children and teenagers need age- and sex-specific percentile charts, which this simple calculator does not implement.
Your data stays on this device
BMI Calculator runs 100% locally. Everything you paste or drop is processed by your own browser and never transmitted. Nothing is stored on our servers — close the tab and it is gone.
Nothing you type is sent to a server, logged, or used for analytics. The page works even with your network disconnected after first load.