Body Mass Index

Body Mass Index is used to figure out how lean or fat you are. It uses a simple formula to calculate a number from your height and weight. It is a variation on the old weight tables that people used to determine if they were under weight or overweight. The old tables had if you were slight framed, average framed and large framed. Then you would look at the combination for your height and weight. With BMI, you just look at your height and weight and it gives you a number. If it is with in a certain range you are normal. Below that you are underweight. Above a range you are overweight. Above that you are obese. The BMI information below is for adult men and women, not children.

How is BMI calculated?

First you need to weigh yourself and measure your height.
Next you need multiply your weight (in pounds) by 703. Call that "A"

Then you take your height (in inches) and square that. Call that "B"
Now you divide "A" by "B".

If you are using metric measures, then just divide the weight (in kilograms) by the height (in meters) squared.

BMI Formulas

For people using pounds and inches, use the following formula.

BMI = ( Weight in pounds x 703 ) / ( Height in inches x Height in inches )

For people using the Metric System, use the following formula.

BMI = Weight in kilograms / ( Height in meters x Height in meters )

BMI Scale

Once you have the number you will want to learn where you stand in the ranking. The BMI scale below will help you understand where you are and where you want to be. Using a BMI calculator is a good way to get you number quickly - calculate your BMI. You can use the BMI chart below to get an idea where you are.

  • Severely underweight less than 16.5
  • Underweight 16.5 to 18.5
  • Normal = 18.5 to 24.9
  • Overweight = 25 to 29.9
  • Obesity Class 1 30.0–34.9
  • Obesity Class 2 35.0–39.9
  • Morbid Obesity 40.0–49.9
  • Super Obese greater than 50

BMI Chart

Body

BMI Disclaimer

BMI is good for average adults who are young. If you are athletic or do body building you will get incorrect results. Also the aged will get incorrect results from using BMI calculations. In athletes and people with muscular builds your body fat may be overestimated. In older people who have less muscle mass, the amount of fat will be underestimated.