What is Body Mass Index?

Body Mass Index (BMI) is an indicator of the amount of body fat for the average person. It’s used as a tool to identify if an adult is at a healthy weight and healthy body fat level.

Before we dive into BMI, let’s first review the benefits of maintaining a healthy weight: 

  • More Energy 
  • Less Joint Pain 
  • Better Sleep  
  • Better regulation of blood pressure (better heart health) 
  • Decreased Risk of Diabetes 
  • Longevity 

These are just a few of the benefits of maintaining a healthy weight, but what does BMI have to do with your weight and what does it mean?

For years, BMI has been used by healthcare providers as a measurement to define if a person has too much body fat, and if so, whether it “presents a risk to health.1 

How to Calculate Your BMI

Since we know maintaining a healthy weight is beneficial for your health, let’s take a look at how to calculate body fat by just using your weight and height.

Calculation: Divide a person’s weight in pounds, by their height in inches. Divide the answer by height in inches. Multiply the answer by 703 (703 is the conversion factor to change units from metrics (meters and kilograms) to imperial (inches and pounds).  

Example: Weight is 140lbs and Height is 5’7” or 67in 

140lbs / 67in = 2.089  

2.089 / 67in = .0311 

.0311 x 703 = 21.9 

BMI = 21.9 


BMI is not a perfect measure and everyone’s body composition is different. BMI is a simple tool of weight-for-height and everyone’s height and weight varies. Therefore, this means BMI is not directly measuring body fat.  

Muscle and bone are denser than fat, which means BMI is not accurately addressing body fat. If an athlete or a muscular person calculated their BMI, their BMI might be high because they have more muscle.

According to BMI calculations they would be considered overweight, however, they don’t have too much fat on their body. Since most people are not athletes, BMI might be a good gauge for body fat.  

Healthy BMI Range 

So, what does this mean for you? The World Health Organization states that a healthy BMI range for adults is between 18 and 24.9. Overweight range for BMI is between 25 and 29.9, and obesity range for BMI is 30 or higher.1 These BMI ranges in adults are the same for men and women, regardless of their age. 

How to Use Your BMI

How should you use BMI? Use it as a gauge or a measure. Our very own LA Fitness Registered Dietitian has some helpful tips on lowering BMI; read about it here.   

If you would like to take your health and body composition to the next level, let us help you achieve your goals with our Pro Results® certified personal trainers. Pro Results® trainers can help identify your personal fitness goals and design a customized workout plan to reach those goals.  

When you make an appointment to start your fitness assessment, it will cover:  

  1. Your current fitness levels 
  2. A body composition test (if desired) 
  3. A personalized timeline to achieve your goals 
  4. An overview of cardio and weight equipment 
  5. And, a quick one-on-one workout 


  1. World Health Organization. Obesity and Overweight Fact sheet detail. February 2018 



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