BMI Calculator
Calculate body mass index (BMI), see a healthy weight range, and review WHO adult screening categories in your browser.
Your result
WHO adult standard
Healthy weight range
- Healthy weight range
- 53.5–72.0 kg
- Distance to range
- 7.3 kg
BMI is a screening measure for adults and is best considered alongside other health information.
Weight categories under the current standard
| Category | BMI range | Meaning |
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Learn more
Formula, range, and standard
BMI (body mass index)uses weight relative to height for adult weight screening. The formula is: BMI = weight (kg) ÷ height (m)².
The healthy weight range is derived from the lower and upper limits of the WHO adult “normal” BMI category, 18.5–24.9.
When BMI should not be used alone
- Under 18: use BMI-for-age percentiles that account for age and sex; adult thresholds do not apply.
- Pregnancy: weight changes require professional assessment using gestational age and pre-pregnancy BMI.
- Athletes or people with high muscle mass: BMI cannot distinguish muscle from fat and may overestimate fat-related risk.
If you have persistent weight changes, chronic-disease risk, or concerns about eating, consult a doctor or registered dietitian.
Examples and common questions
170 cm, 65 kg: 65 ÷ 1.70² = 22.49, which is in the normal range under the WHO adult standard.
180 cm, 81 kg: 81 ÷ 1.80² = 25.00, which is overweight under the WHO adult standard.
Why does the result have two decimal places? The calculation uses full browser precision and displays two decimal places; classification uses the unrounded value.
Tool information and source
This tool does not upload entered data or require an account or backend service. Results are for general health information only and are not medical advice, diagnosis, or treatment.
Reference:World Health Organization: Obesity and overweight. Page updated: .