Is Body Mass Index (BMI) Obsolete?

Body Mass Index (BMI)has been used over the years as an indicator of one’s health.

John Iovine


The formula for calculating BMI was developed in 1832 by Belgian astronomer and mathematician Adolphe Quetelet.

To calculate BMI, you take your height in meters square and divide it by your weight in kilograms.

To convert the formula using imperial measurements of pounds and inches, take your weight in pounds, multiply that by 703, and divide by your height in inches squared.


The results of this calculation will give a BMI number that will classify the person in one of four categories:

A BMI of 18.4 or lower puts one into the “underweight” category.

A BMI of 18.5–24.9 is the “normal” range.

A BMI of 25–29.9 is the “overweight” category.

A BMI of 30 or greater is the “obese” range.

What’s Your BMI?

Let do a basic BMI calculation to see how this works. Our example is a 200 lb male with a height of 5'10".

For imperial, covert the height 5'10" to inches we have 70".

Plug these numbers into the formula:

(200 x 703)/702 = 140600/4900 = 28.7 BMI

In metric

To convert 70 inches to meters, we divide by 39.37, which equals 1.79 meters

To convert 200 pounds to kilograms, we divide by 2.2, which equals 91 kilos.

Plug those numbers into the formula;

91/ 1.792 = 91/3.2 = 28.4 BMI

The slight differences in the BMI is due to rounding off errors

BMI to Access Health was Never Correct

BMI doesn’t discriminate between the body’s lean muscle mass and fat. Because of this, it easily misclassifies people as being obese. Imagine declaring a bodybuilder with 10% body fat classified as obese because of their BMI. It’s happened.

In 1985 the National Institute of Health (NIH) first tied a person’s BMI to determine obesity.



John Iovine

Science writer, thinker, self-experimenter, focusing on personal development and health —