BMI Calculator

Calculate Body Mass Index (BMI) and WHO weight classification category.

Category: Calculators

How to Use BMI Calculator

Enter your body weight in kilograms (kg).
Enter your height in centimeters (cm).
Click 'Calculate Body Mass Index' to instantly compute your BMI score.
Review your BMI value, WHO weight classification category, and copy your results.

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Frequently Asked Questions

What is Body Mass Index (BMI) and what is the formula?

Body Mass Index (BMI) is an internationally recognized anthropometric metric that compares body weight to height. The formula is BMI = weight (kg) / [height (m)]². It provides a standardized baseline for assessing underweight, healthy weight, overweight, and obesity.

What are the official WHO BMI categories for adults?

World Health Organization (WHO) categories for adults are: Underweight (BMI < 18.5), Normal weight (18.5 ≤ BMI < 25), Overweight (25 ≤ BMI < 30), and Obesity (BMI ≥ 30).

Why does BMI not differentiate between muscle mass and body fat?

BMI calculates total body mass relative to stature but does not distinguish between adipose tissue (fat) and lean muscle or bone density. Muscular athletes may have an elevated BMI despite low body fat, while older adults may have a normal BMI with elevated fat percentage. BMI is an anthropometric screening indicator for adults 20 and older, not a clinical medical diagnosis.

Is this BMI Calculator confidential and private?

Yes. All computations run 100% locally in your web browser. No weight, height, or personal health metrics are ever transmitted across the network or stored on external servers.