EMG Health Numbers: Body Mass Index

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Man on Scale

Body Mass Index (BMI) is a popular method, which health care professionals use to evaluate body composition based on an individual’s height and weight. A BMI below 18.5 is considered underweight. A normal BMI ranges between 18.5 and 24.9. A BMI between 25 and 29.9 is overweight. A BMI greater than 30 is obese.1

To determine your BMI, enter your information into EMG’s BMI Calculator with height in inches and weight in pounds. The chart below categorizes the ratios and provides a description.


Limitations of Body Mass Index

While BMI is a well-known method for measuring body composition, it is not necessarily the best. BMI does not take into account an individual’s body type or composition (the ratio of muscle mass to fat mass. This causes the ratio to be inaccurate for men with a higher percentage of muscle mass and a lower percentage of body fat.1

For example, a man who loses 10 lbs of fat and gains 10 lbs of muscle will have the exact same BMI but will likely be much healthier. Therefore, BMI may not be an accurate predictor of common health problems such as diabetes, high blood pressure, and heart disease in certain individuals. Another, potentially more accurate numerical assessment of overall health is the waist-to-height ratio (See EMG Health Numbers: Waist to Height Ratio). 

Body Mass Index


<18.5 Underweight
18.5 – 24.9 Normal Weight
24.9 – 29.9 Overweight
30.0 – 34.9 Obese (Class 1)
35.0 – 39.9 Obese (Class 2)
> 40.0 Morbidly Obese

EMG Health Numbers Homepage: Health Numbers

External Resources: National Institute Of Health: BMI

Updated: May 12, 2015


1. Osama H. Obesity. http://emedicine.medscape.com/article/123702-overview: Medscape Reference; 2012.