BMI Calculation

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Your BMI is:

BMI Chart

Weight Status Body Mass Index
Underweight Below 18.5
Normal 18.5 to 24.9
Overweight 25.0 to 29.9
Obese 30.0 and Above

What is BMI?

BMI or body mass index is defined as the body weight in kilograms divided by the square of the height of the body in meters. The standard unit of body mass index is kilograms per square meter. The body mass index is a rule of thumb devised by a Belgian mathematician and philosopher in the early 19th century. It was originally created for population study and not an individual medical examination. The value of the body mass index gives a very broad idea about the health of a person based on the tissue mass. Body mass index can be calculated using a graphic chart or a table. It is important to keep in mind that BMI is not a diagnostic procedure, but merely a norm.


Body mass index measures the size of a human body taking into account the height and weight. It is not a diagnostic measure. However, it is very convenient for medical professionals to apply a rule of thumb to the general public. Body mass index allows medical professionals to broadly classify a person as Underweight, Normal, Overweight or Obese. Diets and exercise plans are recommended by dieticians on the basis of the body mass index value. High body mass index values have been directly correlated with higher risk of vascular diseases, diabetes, abnormal blood pressure etc. Low values of body mass index are correlated with eating disorders, chemical imbalances etc. Thus abnormal values of body mass index are suggestive of the disorder, which allows the appropriate diagnostic tests to be conducted. However, it is to be remembered that there are exceptions to this thumb rule. For example, athletes with high muscle mass can get high values of BMI, without having any disorders.

BMI Calculations

Body mass Index is found directly by dividing the body mass in kgs by the square f height in meter square. The inferences that can be drawn from the specific body mass index value is presented in the form of a table or a chart. This table or chart gives the range of the BMI values that represent a body type.  BMI value below 18 shows that the subject is underweight; a value between 18 and 25 shows that the subject has a normal weight with respect to his or her height; a value between 25 to 30 shows that the subject is overweight and a value above 30 classifies the subject as obese. The limits of these ranges can vary a little according to the test administrators, race, age, sex etc. The chart offers a more detailed analysis. It is divided into various sub zones inside the main categories of underweight, normal, overweight and obese.


A variety of inferences can be drawn from the body mass index. The chart allows you to plot the exact difference between the healthy body state and the current state. This allows for recommendation of diet plans etc. Broad inferences such as risk of diabetes, blood pressure, cardiovascular disease etc. can also be drawn from the body mass index value. Medical professionals can also predict a general tendency of weight gain from the BMI value, also known as weight stability. Online BMI calculators are, however, much less reliable. They do not take into account fat ratios, waist dimensions and lean muscle mass. This may lead to many erroneous results. Factors affecting body mass index include alcohol consumption, smoking and any other drug consumption. These factors must be considered before recommending effective diet and exercise plans.

BMI Dependence on age

Body mass index values and conclusions from them depend upon the age of the person. As the age increases, the zones of the BMI ranges keep shifting towards the positive side. So a teen and a man in his fifties having the same body mass index value will not lie in the same zone. Much research has been conducted and exact curves of healthy BMI values with respect to age have been found.  Considering these curves give much more accurate results. BMI is also dependent on the sex of the person along with many other genetic factors as well as habits.

BMI Dependence on race

The inferences to be drawn from body mass indexes also depend on the ethnicity of the subject. Generally, people of Asian ethnic origins have a higher percentage of fat when compared to Caucasian Latin American counterparts. Therefore, a similar body mass index may represent higher risks of disease for people of Asian origins. Various studies have compared the obesity tendencies, transition rates and tendencies of other cardiovascular diseases among various races.


Body mass index is an important indicator of a person’s health, and general body trends. It helps medical professionals broadly categorise a person and thus get a directive for beginning diagnosis. However, it is crucial to remember that BMI is not a diagnostic test in itself and must not be relied upon to reach inferences.