Body Mass Index

Author: Kristina Magathova   Date Posted:14 January 2016 

Body Mass Index main image Body Mass Index image

better-than-bmi-main.jpgWeight determines our health. We all should be aware of our body composition – lean muscle mass but also fat we are carrying in our bodies.

BMI is probably the most common option for identifying risks associated with obesity or, on the other side, underweight.

Do you know what BMI means?

BMI means Body Mass Index – a simple index of weight vs. height. - one of the methods used to classify underweight, overweight and obesity, particularly in adults.



What is the purpose of measuring BMI?

This is a number that will assess your weight with respect to your height. In other words, the height will show you whether your weight is appropriate or not. The higher your BMI number is, the higher the category of medical risk you fall into.

How do I calculate BMI?

You can calculate your BMI by using the Quetelet index. It is very simple: BMI = weight in kg / (height in m) ². The result you get is a two –digit number that can be found in the table (chart) to indicate the suitability of your weight to your height.

How accurate is BMI?

The BMI formula is not entirely accurate; however it is not far from the correct result provided by specialists. Only a specialist would be able to identify your “perfect” weight.

Keep in mind, the number you get from the formula is likely to be very similar to the truth (difference can be +/- 3-4%).

Does BMI calculate body fat?

It is important to know that the BMI does not determine how much body fat is stored in your body. It is just an easy and inexpensive way to find out whether you are at normal weight or there are signs of overweight, possibly obesity.

Are there any exceptions?

BMI is good weight indicator only for people of typical stature and normal muscle distribution. BMI calculation does not apply to professional athletes who have a higher ratio of muscle mass than non-athletic people.

Loss of muscle mass, e.g. during extreme dieting, can also give inaccurate BMI readings.  BMI can indicate weight gain after dieting as normal; however this is typically increase in fat weight rather than the muscle mass previously lost.

What are the "good" numbers?


The best BMI numbers are between 20 and 25. This indicates a normal weight that is appropriate to your height. Numbers over 25 are considered as overweight and numbers below 20 underweight. The higher the number, the heavier you are in relation to your ideal weight.

If the number comes close to 30, you should consider seeing a specialist and perhaps making some lifestyle changes - start with diet & exercise. A number over 30 is a sign of obesity and only increasing movement and changing diet will help to establish a healthier lifestyle.


Active Mobility Systems has a wide range of scales, including scales that are able to measure BMI. With these scales you can regularly check your BMI and see your improvements. The number you get from these scales might be slightly different than the number you get from a specialist but the difference is usually only +/- 3-4%. For people who want more information about their state of health, they can consider a Body Composition Scale which tells them not only their weight but also:

  • Basal Metabolic Rate (BMR)
  • Total Body Water (TBW)
  • Fat Free Mass (FFM)
  • Fat Percentage
  • Fat Mass
  • BMI


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