BMI Calculator

Our BMI Calculator is a simple online health tool that helps you estimate your Body Mass Index using your height and weight. BMI is commonly used as a quick screening method to understand whether a person may be underweight, within a healthy weight range, overweight, or in the obesity range. This tool supports both metric units and imperial units, so you can calculate your BMI using centimeters and kilograms or feet, inches, and pounds.

What Is BMI?

BMI, or Body Mass Index, is a numerical value that compares your body weight to your height. It does not directly measure body fat, but it can give a useful general indication of whether your weight is appropriate for your height.

BMI is often used by adults as a basic health screening tool. However, it should not be considered a medical diagnosis. Factors such as muscle mass, age, body composition, pregnancy, and athletic training can affect how BMI should be interpreted.

BMI Formula

The BMI formula depends on the unit system you use.

Metric BMI Formula

If you are using kilograms and meters, the formula is:

BMI = weight in kg ÷ height in meters²

Example:

If your weight is 70 kg and your height is 1.75 m, your BMI is:

70 ÷ 1.75² = 22.9

Imperial BMI Formula

If you are using pounds and inches, the formula is:

BMI = weight in lb ÷ height in inches² × 703

Example:

If your weight is 154 lb and your height is 69 inches, your BMI is:

154 ÷ 69² × 703 = 22.7

How to Use the BMI Calculator

Using this BMI calculator is easy. First, choose your preferred unit system: Metric or Imperial. If you select metric, enter your height in centimeters and your weight in kilograms. If you select imperial, enter your height in feet and inches, then enter your weight in pounds.

After entering your details, click the Calculate BMI button. The calculator will instantly show your BMI score, BMI category, BMI Prime, and a healthy weight range based on your height. You can click the Reset button to clear the fields and start again.

BMI Categories

The calculator uses standard adult BMI categories:

BMI Range	Category
Below 18.5	Underweight
18.5 – 24.9	Healthy weight
25.0 – 29.9	Overweight
30.0 and above	Obesity range

These categories are general guidelines. A person with high muscle mass may have a higher BMI without having excess body fat. Similarly, BMI may not be suitable for children, teenagers, pregnant people, or some older adults.

What Is BMI Prime?

BMI Prime compares your BMI to the upper limit of the healthy BMI range, which is 25.

BMI Prime = BMI ÷ 25

A BMI Prime below 1 means your BMI is below 25. A BMI Prime above 1 means your BMI is above the standard healthy range.

Why Use This BMI Calculator?

This tool is useful because it gives fast, clear, and easy-to-understand results. It works on desktop, tablet, and mobile devices, and it supports both major measurement systems. Along with your BMI score, it also provides a visual BMI meter, category explanation, and estimated healthy weight range.

Important Health Disclaimer

BMI is only a screening tool. It should not replace advice from a doctor, dietitian, or qualified healthcare professional. For a complete understanding of your health, consider other factors such as waist circumference, nutrition, exercise habits, medical history, and body composition.