Body Mass Index (BMI) is a method of calculation that relates a person's weight to his/her height. This revolutionary method was invented between the years of 1830 and 1850 by Adolphe Quetelet, who was a Belgian polymath. For this reason, it is often referred to as the Quetelet calculator.
It is a widely-used diagnostic tool to identify the health of a person. This calculation technique does not measure a person's percentage of body fat, but can be used to gauge a healthy body weight in relation to height. BMI has 3 basic categories of weight―underweight, healthy, and obese. It thus identifies if a person has any kind of weight problem.
The basic formula used is the division of an individual's body weight by the square of his or her height. The result obtained from this calculation is unit measure of kg/m2. This is then related to a BMI chart or graph, which shows BMI as a relation between weight on the horizontal axis and height on the vertical axis.
These are simple steps to calculate one's BMI:
- Multiply your weight in pounds by 703.
- Divide that answer by your height in inches.
- Divide that answer by your height in inches again.
This chart can be used to assess what category your BMI falls into, and steps can be taken if you are underweight or overweight.
|18.5 - 24.9||Healthy|
|25.0 - 29.9||Overweight|
|30.0 - 39.9||Obese|
|Over 40||Morbidly obese|
The BMI method has come under a lot of fire as it is too generalized and not suitable for everyone. People such as bodybuilders or any person having significant muscle mass may have a high BMI, and yet not be overweight. It is also a known fact that muscle weighs more than fat.
While assessing the weight of children, age plays an important factor, and so this is often considered an inappropriate approach to evaluate a child. Similarly, for the elderly, different factors come into consideration. One such factor is that a slightly higher BMI may help those older that 65 from osteoporosis.
As an answer to many of these issues, the advanced BMI calculator was developed. Most advanced calculators include age and gender in the formula. One calculator includes very important factors of gender, waist, and hip size. It thus takes into consideration the waist to hip ratio.
While an advanced calculator may provide you with a better assessment of your health, it is best to consult your doctor. Only a medical practitioner can assess if you are truly healthy. To ascertain good health, several other factors also such as blood pressure and cholesterol need to be taken into consideration.
If you are overweight, and wish to find out your percentage of body fat, certain other tests such as bioelectric impedance assay (BIA) or hydrodensitometry (underwater weighing) may be carried out. The American Council on Exercise says that the acceptable body fat percentage for adults is 18 - 24% for men and 25 - 31% for women.