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BMI Calculator

Based on the standards of the WHO

Body Mass Index (BMI) is a convenient rule of thumb used to broadly categorize people as underweight, of normal weight, overweight, or obese. Since the 1980s, BMI has been used as a standard by the World Health Organization (WHO) in national obesity statistics and research.

In clinical practice, BMI is generally regarded as a satisfactory tool for determining whether individuals are overweight or underweight.

To calculate your BMI, fill out your details below.


The Body Mass Index (BMI), also known as the Quetelet index, is a standardized method to express a person's body weight. It is calculated by dividing a person's body mass by the square of their body height. The resulting value is one's BMI in kg/m2. Depending on how low or high this value is, a person is usually classified as underweight, of normal weight, overweight, or obese.

The BMI index was created between 1830 and 1850 by Adolphe Quetelet, a Belgian scientist and mathematician. While not a fully comprehensive way of assessing one's physical health, it is widely known and used due to its simplicity. Because it accounts for not just mass but also height, it gives a more accurate picture of one's health than does simply measuring body mass alone. Since the 1980s, the BMI has been used as a standard by the World Health Organization (WHO) in calculating national obesity statistics.

Various systems of expressing one's raw BMI value as a weight class exist; a commonly used one is that of the WHO. According to the WHO, a BMI under 18.5 is underweight, and sometimes indicative of malnutrition, an eating disorder, or other health problems. A BMI between 18.5 and 25 is considered healthy weight, while a BMI over 25 is seen as overweight and one exceeding 30 is obese. An excessively high BMI is a risk factor for various diseases including coronary artery disease, hypertension, stroke, and cancer.

The present test is intended for educational and entertainment purposes only. IDRlabs International and the present test are independent from any researchers, organizations, or their affiliated institutions. Free online tests such as this are merely a beginner's exploration into the concept being examined and cannot provide entirely accurate assessments of your physical health. This test is to be used for screening purposes only. Any potential diagnoses can be made only by a physician or other health professional.

As the publishers of this free online test, which allows you to find out your BMI and what your body class is according to the WHO classification, we have strived to make the test as reliable, valid, and comprehensive as possible, by subjecting this test to statistical controls and validation. Though developed and statistically validated by psychology professionals, free online tests and quizzes such as the present one do not provide professional assessments or advice of any kind; the present test results are provided “as-is.” For more about this test or any of our other online tests, please consult our Terms of Service.

Why Use This Test?

1. Free. This online BMI Calculator is delivered to you at no charge and will allow you to obtain your Body Mass Index (BMI) to see whether you are underweight, of normal weight, overweight, or obese according to the classification employed by the World Health Organization (WHO).

2. Validity and reliability. Although BMI, as any measure, is not wholly comprehensive and should ideally be used in combination with other metrics like waist circumference, it is a valid and reliable measure of body weight and potential associated health issues. Used by the WHO, it is one of the most popular body weight metrics worldwide, thanks to its ease of use and its inclusion of body weight and height as its criterions.

3. Relevant to increasing health awareness. Rates of obesity in Western countries have raised serious public health concerns. The present test can be useful to those involved.

4. Statistical controls. User results for the present test are logged into an anonymized database, and statistical analyses are performed to ensure results are as valid and reliable as possible.