BMI Calculator (Male, Female, WHO, Health)
Switch between metric and imperial measurements, see your BMI instantly, and learn how it maps to standard weight ranges.
Calculate your body mass index using metric or imperial units.
Calculate adult body mass index (BMI) using metric or imperial units and compare the result against standard WHO adult categories. Useful for a quick screening check, personal tracking, or wellness intake forms when you need a simple baseline.
How this page is maintained
- Steps and copy are checked against the current tool behavior.
- Browser limits, file-size constraints, or compatibility gaps are documented when relevant.
- Unless a page explicitly says otherwise, files and text stay in the browser during processing.
What BMI is useful for
BMI is a screening metric, not a diagnosis. It gives you a fast baseline using only height and weight, which is why it is still widely used for intake forms, broad health screening, and personal progress tracking.
How the calculation works
For metric inputs, BMI is your weight in kilograms divided by the square of your height in meters. For imperial inputs, the tool converts feet, inches, and pounds into the same formula automatically. The categories on this page follow the standard adult WHO ranges from underweight through obesity class III.
Important limits of BMI
BMI does not measure body fat percentage, muscle mass, bone density, pregnancy, or age-specific growth patterns. That means very muscular adults, older adults, pregnant people, and children can all need a different interpretation. This page is best used as an adult screening reference, not as a medical verdict.
Privacy and practical use
All calculations run locally in the browser. If you want medical advice, use the result as a conversation starter with a clinician rather than relying on BMI alone.
Key features
- Dual units: Use centimeter/kilogram inputs or switch to feet/inches/pounds in a single interface.
- Auto classification: See the WHO category (underweight to class III obesity) immediately after calculating.
- Shareable stats: Use the result as a quick screening reference for personal tracking, intake forms, or a simple wellness check-in.
Frequently asked questions
How accurate is BMI?
BMI is a screening metric, not a diagnostic tool. It does not account for muscle mass, bone density, or body composition. Athletes may have a high BMI but low body fat.
Is BMI different for men and women?
The standard formula is the same for both adults. However, women naturally have more body fat than men at the same BMI. Interpretation should vary by gender and age.
Does this work for children?
No. Children and teens need "BMI-for-age" percentiles (growth charts) because they are still growing. This calculator is for adults (20+).
What is a "healthy" BMI?
According to the WHO, a BMI between 18.5 and 24.9 is considered healthy for most adults. Below 18.5 is underweight, and 25.0 or higher is overweight.
Why does waist size matter?
Waist circumference measures abdominal fat, which is a higher risk factor for heart disease and diabetes than hip or thigh fat. It is a good companion metric to BMI.