How Is BMI Calculated, & Why Is It Important?
to Know Your Health Status
One of the tools used to measure your health (at least an aspect of it) is the body mass index (BMI) or BMI calculator. The calculator uses a BMI formula that allows you to know whether you’re considered underweight, normal, overweight, or obese.
When it comes to your health, you should never neglect any inconsistency and indication of possible illness.
In this article, you’ll learn what BMI means, how it’s calculated using the Body Mass Index formula, and how you can use this information to improve your health.
What is Body Mass Index (BMI)?
The body mass index takes both your height and weight in relation to your age to indicate whether your current body weight is within a healthy range. With this information, you’ll be able to determine whether you are malnourished, underweight, normal, overweight, or obese.
You can use a BMI chart to determine your category. The Adult Body Mass Index (BMI) chart created by the University of Vermont is considered a standard example. Knowing your BMI and how to calculate it will make you aware of your bodily limitations. As more and more people adopt a sedentary lifestyle, your BMI score can serve as a warning for people to start taking their health more seriously.
What is the Purpose of Knowing Your BMI?
Your BMI score (depending on how high it is) can be an early detection sign of many diseases including:
(Many of these diseases are chronic conditions associated with obesity: obesity and cancer, obesity and type 2 diabetes, and sleep apnea and obesity).
- High blood pressure
- Cardiovascular problems
- Type 2 diabetes
- Musculoskeletal problems
- Malnutrition
- Anemia
- Osteoporosis
- Sleep apnea
- High cholesterol
- Liver disease
- Arthritis
- Cancer
Unfortunately, the more obese or overweight you are, the more susceptible you are to breast cancer, prostate cancer, and colorectal cancer.
Data from the World Health Organization show that around three million people die each year due to obesity.
Does obesity cause strokes? Yes, obesity poses a greater risk of stroke.
What Is the Formula for Calculating BMI?
You’ll be surprised to know that calculating BMI is quite simple.
All you need is the following information:
- Height in meters or inches
- Weight in kilograms or pounds
Here is the BMI formula: BMI = weight (kg)/height (m)2.
Or you can use this BMI formula instead if you prefer: BMI = weight (lb)/height (in)2 x 703.
To provide you with a hypothetical example, consider this: Josie is a 25-year-old woman working as a banker. In her latest medical exam, she was 170 centimeters (1.7 meters when converted to calculate the BMI) and weighed 70 kilograms. Her BMI result was 24.22, a healthy score.
BMI = 70 kilograms / 1.7 meters2
BMI = 24.22 (HEALTHY)
If you don’t have the time to determine your BMI, you can always use our BMI calculator, which is designed to give you accurate and quick results.
Use the Adult Body Mass Index chart to check if your BMI falls within the healthy range.
What If BMI Tools Indicates You’re Overweight or Obese?
Don’t worry, you don’t need to panic. As mentioned earlier, BMI is just one health indicator among many. There are many factors that can influence your BMI ratio too.
The best thing to do next is to book an appointment with your physician and share your BMI results.
Remember the BMI calculator is not a diagnostic tool for any diseases, but it can be a warning.
Here are more tips for maintaining or losing weight for a healthier you:
- Talk to your physician to get the most suitable weight loss program for you. A lot of programs promise instant weight loss, but many of them are “too good to be true” and don’t really work for everyone. It might even do you more harm than good.
- Engaging in 120-150 minutes of moderate aerobic exercise will help you break a sweat. Be careful, though, as not all exercises are appropriate for everyone. Ask your doctor first to determine whether you should avoid certain physical activities.
- Write down your eating habits. Keeping a food diary will make you more conscious of the food choices you make. As such, it’s easier to tweak habits that prevent you from reaching your optimum health.
What are the Limitations of Body Mass Index (BMI) Calculators?
Although a BMI calculator comes in handy, it isn’t an absolute measure of health.
A CDC study showed that age, sex, ethnicity, and muscle mass could affect overall BMI correlation and body fat.
Other factors that can skew your normal BMI result are:
- Muscle mass
- Body fat percentage
- Muscle and bone composition
Nevertheless, using a BMI calculator and BMI chart can give you a bird’s eye view of your current health status, which is valuable insight into how you can start to break bad habits and start healthier ones.

I do not use BMI as a sole criterion in determining one's candidacy for surgery.
As all patients have individual differences and surgical nuances, a high BMI score should not prevent them from achieving their plastic surgery goals.

Nick Masri MD
Double Board Certified Plastic Surgeon