Body mass index (BMI) purports to be a measure of body fat based on height and weight that applies to both adult men and women.
BMI Categories:
The idea of this page is that the standard Body Mass Index (BMI) is inherently flawed because it assumes that a body's mass increases as the square of the height. Generally mass increases with the cube of the linear dimensions, so a formula using the square will skew to higher BMI's for tall people. The formula for the standard BMI in inches and pounds is taken from the National Heart, Lung, and Blood Institute web page; this is the same as used at the Center for Disease Control page.
BMI = 703 * (weight / height^2)
For mass varying with the cube of height we would use this formula:
BMI = 47804 * (weight / height^3)
Actually, though, the mass does not increase by the cube of the height except when all dimensions of an object grow proportionately. For humans this is generally not the case, and somewhere (perhaps in T.W. Körner's The Pleasures of Counting, but perhaps not) the author read that the correct value should be 2.2. Thus the final BMI is calculated with the formula:
BMI = 1634.771687 * (weight / height^2.2)
Here is the applet which does these calculations.
These BMI's must be normalized: to do so we take a "healthy" BMI for a 68 inch (172.72 cm) 151.283 pound (68.7 kg) person to be 23.0; i.e., for such a person all three BMI's will be 23.0.
Of course, this is all rather meaningless for an individual, as any such simple formula ignores relevant factors in what should be should be considered a healthy weight. A Google search for "Body Mass Index" will find more than you can read.
Note: The applet should appear in the box above. If a red X appears, then you need to install the Java Plug-in, which happens automatically when you install Java (click on "Get It Now"). You can find more information at the Java Plug-in home page .
This applet was developed by Glenn Murray around the turn of the millenium when he was learning Java (note the lurid colors!). Glenn is rather tall.