BMI Calculator

Your BMI Result

Your BMI is compared with commonly used adult BMI categories.

How Your BMI Was Calculated

BMI is calculated by dividing weight in kilograms by height in metres squared.

BMI Categories

These commonly used categories are intended for adult screening. They should be interpreted alongside other information about a person's health and circumstances.

What Is BMI?

Body Mass Index, commonly called BMI, is a numerical measure based on a person's weight and height. It is commonly used as a screening measure to group adults into weight categories.

BMI is useful because it provides a simple way to compare weight with height. However, it does not tell you exactly how much body fat you have or where that fat is located.

For that reason, BMI is best viewed as one piece of information rather than a complete assessment of health.

How to Use the BMI Calculator

1. Enter your current weight.
2. Select either kilograms (kg) or pounds (lb).
3. Select the height format you want to use.
4. Enter your height in feet/inches, centimetres, or metres.
5. Click Calculate BMI.
6. Review your BMI category and the reference weight range shown with the result.

Understanding Your BMI Result

A BMI result is a screening value rather than a diagnosis. Two people with the same BMI can have very different body compositions and health profiles.

For example, a person who has substantial muscle mass may have a higher BMI because muscle is relatively dense. BMI may therefore classify some muscular people as overweight even when their body-fat level is not high.

Similarly, BMI does not show how fat is distributed around the body. Other measurements and health information may provide additional context.

What Does the Reference Weight Range Mean?

The reference weight range shown by this calculator is calculated from the adult BMI range of 18.5 to 24.9 at the height you entered.

It is mathematically derived from the BMI categories and should not be interpreted as a personalised medical recommendation or a required target weight.

Common Uses of a BMI Calculator

• Checking a general weight-to-height ratio.
• Learning how BMI categories are defined.
• Tracking changes in BMI over time.
• Understanding the mathematical relationship between height and weight.
• Using BMI as one screening measurement when discussing general health with a professional.

Important BMI Limitations

BMI is useful as a general screening measure, but it has important limitations.

• It does not directly measure body fat. BMI is calculated only from height and weight.
• Muscle mass can affect the result. Highly muscular people may have a high BMI without having excessive body fat.
• It does not show fat distribution. BMI does not indicate where body fat is stored.
• It is not a diagnosis. A BMI category alone cannot determine whether someone is healthy or unhealthy.
• Children and teenagers are different. BMI interpretation for children and adolescents generally takes age and sex into account and should not simply use adult BMI categories.
• Pregnancy requires different considerations. Adult BMI calculations should not be used to assess pregnancy weight status in the same way.

Tips for Getting a More Useful BMI Result

• Use your current weight rather than an old measurement.
• Measure your height accurately, preferably without shoes.
• If using feet and inches, make sure the inches value is below 12.
• When tracking changes, try to measure under similar conditions each time.
• Do not judge overall health from BMI alone.
• If you have concerns about your weight or health, consider discussing the result with a qualified healthcare professional.

Privacy and Data Processing

This calculator performs the BMI calculation directly in your web browser. The weight and height values entered into the calculator are used to produce the result on the page.

Because the calculation can be performed locally, there is no need to send your measurements to a server simply to calculate BMI. As with any website, avoid entering sensitive information on shared or untrusted devices.

Frequently Asked Questions