The abbreviation "BMI" stands for Body Mass Index. The United States Centers for Disease Control and Prevention, or CDC, use BMI as a measure of body fatness based on height and weight. By calculating your BMI, you can begin to assess your risk for diseases and health problems related to body fat and obesity.
Calculating BMI
To calculate your BMI using measurements in pounds and inches, divide your weight in pounds by your height in inches, squared. Then multiply that value by 703. For example, if you weigh 135 pounds and you measure 60 inches tall, divide 135 by 3600, the square of 60, and multiply the resulting value by 703. You should find that you have a BMI of 26.3625.
Interpreting BMI
The CDC website lists guidelines for interpreting adult BMI values. These guidelines classify adults with BMI values under 18.5 as underweight and adults with BMI values over 30.0 as obese. Adults with BMI values between 18.5 and 24.9 have normal or healthy weight, and adults with BMI values between 25 and 29.9 are overweight. These guidelines only apply to individuals 20 years old or older.
BMI for Children And Teens
You can calculate the BMI value for a child or teen the same way you would for an adult. However, the CDC provides age- and gender-specific BMI interpretation guidelines for children and teens. To find out more about the BMI of a specific child or teen, visit the CDC's online "BMI Percentile Calculator for Child and Teen" (See References). When you enter the child or teen's weight and height and calculate her BMI value, you can then view a personalized growth chart for that child or teen.
BMI Inconsistencies
A woman with the same BMI value as a man will often have more body fat than the man. Women naturally have higher body fat percentages than men. Trained athletes with increased muscle mass will often have lower body fat percentages than average individuals with the same BMI value.
Related Considerations
The CDC points out that you should consider other factors in addition to BMI when assessing your risk for diseases related to obesity and high weight. These other factors include waist size, physical activity and preexisting conditions.
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