What is my BMI?

Body mass index or BMI, indicates whether or not an individual is of a healthy weight. BMI is based on a person’s height and weight. Medical and health care professionals use BMI to determine whether someone is underweight, overweight, obese, or healthy.

BMI is calculated with a simple formula: weight in kilos divided by height in metres squared.

So a person who is 1.8 metres tall and weighs 140 kilos, would calculate their BMI as follows:

1.8 x 1.8 = 3.24
140/3.24 = 43.2

The BMI of this individual is 43.2

A person’s BMI will fall into one of five categories, which are underweight, ideal, overweight, obese, and very obese.

Underweight 18.5 or lower
Ideal 18.5-25
Overweight 25-30
Obese 30-40
Very obese 40 or greater

BMI is not always an accurate indicator of an individual’s health. Athletes, for example, have muscle masses that may push them into the overweight or even obese categories, despite the fact that this is clearly not the case. Pregnant women will also have inaccurate results when measuring their weight using BMI.

BMI may not be accurate in some cases because it fails to take body fat percentages into consideration. Despite the fact that it is not accurate for everyone, the average person can use it as a reliable guide when determining how healthy their weight is.

BMI can be an important factor in weight loss surgery. Most surgeons will not perform weight loss procedures on patients who do not have BMI’s above 30. A patient’s BMI may also play a role in which weight loss procedure the surgeon chooses to perform. Those with extremely high BMI’s may not qualify for invasive surgeries due to potential health risks.

The BMI was created for adults, however because childhood obesity is on the rise many parents are looking for ways to determine whether their children are overweight or obese. BMI can be used to determine whether children or teens are at a healthy weight, however, physicians or other health professionals may have more age specific charts or tables.