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Smart BMI Calculator

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 obesity statistics and research. Smart BMI is an improved measure of the standard BMI that factors in age and gender to provide a more comprehensive result.

To calculate your Smart BMI, fill out your details below.


The Body Mass Index (BMI) is a standardized method to express a person's body weight. The Smart BMI (SBMI) was created by biologist Christian Bachmann, in cooperation with David Fäh, M.D. and Heinrich von Grünningen, M.D. This site is not affiliated with Bachmann, Fäh, or von Grünningen and not the equivalent of their Smart BMI Calculator.

The Smart BMI data is based on the best studies available, using the closest possible match between the graphical result feedback and the study results. For some population groups, such as very old people, the data is sparser and thus less reliable.

Among the many advantages of Smart BMI is that age-related height loss and age-related muscle loss are factored in. The Smart BMI index also factors in sex differences, accounting for women's overall higher tendency to accumulate body fat.

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

As the publishers of this free online test, which allows you to find out your Smart BMI and your health risk according to peer-reviewed scientific papers and the general improvements made to the WHO BMI indices, we have strived to make the test as reliable, valid, and comprehensive as possible, by subjecting it to statistical controls and validation. Please note that free online tests and quizzes such as this 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 Smart BMI Calculator is provided to you for free and will allow you to obtain your Smart BMI (sBMI) to see whether you are underweight, of normal weight, overweight, or obese, according to the classification employed by the World Health Organization (WHO) and further improved by Bachmann, Fäh, and von Grünningen.

2. Based on peer-reviewed research. Although BMI, as any measure, is not wholly comprehensive, the present values and charts of this Smart BMI Test are based on adjusted values found in peer-reviewed studies and papers.

3. Improved measure of the WHO BMI. The WHO’s measure of BMI has been subjected to sustained criticism for many years. Smart BMI proposes to rectify some of these critiques.

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.