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BMI Calculator— Free & Private

Calculate your Body Mass Index instantly with metric or imperial units.

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BMI Scale

Underweight< 18.5
Normal18.5 – 24.9
Overweight25 – 29.9
Obese≥ 30

Your BMI

24.2

Normal

All calculations happen in your browser. No data stored.

What Is BMI?

Body Mass Index (BMI) is a numerical value calculated from your weight and height that provides a general indication of whether your body weight falls within a healthy range. The formula divides weight in kilograms by height in meters squared. While BMI does not directly measure body fat, it is a widely used screening tool in healthcare for identifying potential weight-related health risks. Our calculator supports both metric and imperial units and runs entirely in your browser.

How to Use BMI Calculator

  1. Select your unit system

    Choose between metric (kg/cm) or imperial (lbs/ft-in) measurements.

  2. Enter your measurements

    Input your weight and height in the selected unit system.

  3. View your BMI result

    See your BMI value, weight category, and where you fall on the BMI scale.

Why Use Our BMI Calculator?

Instant BMI calculation with no data stored
Supports both metric and imperial units
Clear visual indicator of your BMI category
Explains what each BMI range means for your health
No personal health data collected or transmitted
Works on any device with a browser
Provides context about BMI limitations

Frequently Asked Questions

What are the BMI categories for adults?

Underweight is below 18.5, normal weight is 18.5-24.9, overweight is 25.0-29.9, and obese is 30.0 and above. These ranges are defined by the World Health Organization.

Is BMI an accurate measure of body fat?

BMI is a screening tool, not a diagnostic one. It does not distinguish between muscle and fat mass, so athletes with high muscle mass may show a high BMI despite having low body fat.

Does BMI apply the same way to all ages?

BMI categories listed here apply to adults aged 20 and over. For children and teens, BMI is interpreted using age- and sex-specific percentile charts.