Body Mass Index Calculator And BMI Reliability Analysis

BMI – What Does Body Mass Index Mean?

Body mass index (BMI) is a standard measure used to assess the amount of fat in the body in proportion to the height and weight of a person.

This is a medically accepted measuring standard to know whether a person is underweight, normal weight, overweight or obese.

BMI is very useful for assessing your weight loss requirements. You can decide upon the amount of weight that needs to be shed or how much weight to be put on if you are underweight to be healthy.

Manual Calculation Of BMI

There are some methods and formulas used for manually calculating BMI. Let us have a look at the two most commonly used BMI measurement methods.

1. Calculation Of BMI In Metric System

The calculation of BMI follows a simple metric system.

BMI is obtained by arithmetically dividing the total weight of your body with the squared sum of your height in meters.

Here is an example that will give you a better understanding of BMI measurement in the metric system.

BMI In Metric System

2. BMI Calculation In Imperial System

The BMI calculation steps followed in the imperial system is a bit different from the metric system of measurements.

STEP 1: The total weight of the body needs to be multiplied by 4.88, a fixed standard number.

The multiplied sum of the body weight in Step 1 needs to be divided by the squared value of the height.

Let us look at a practical example to understand this BMI calculation better.

BMI Imperial System

There are also other formulas used for measuring BMI.

BMI And Weight Categorization

The below-given charts will help you to identify your weight category.




Health Risks Warning From BMI

If your body weight is falling under the Underweight or Obesity level weight category, you need to make changes in your diet and nutritional habits; and if required suitable medical treatment for the same. The overweight category is also bad and needs your special attention to reducing body weight.

Your health is in very bad shape if your BMI is above 30; this is in the high-risk category of developing diabetes, cardiovascular diseases, heart attacks, stroke, etc.

The very low body mass index is as dangerous as the obesity category. They are highly prone to all common diseases and general weaknesses.

Is BMI A Reliable Health Indicator?


There is a divided opinion on the reliability of body mass index measurement. Many doctors and health experts say BMI is not a foolproof measurement to be relied upon.

There are numerous instances where people appeared to be overweight, but they continued to live healthy life with no health hazards.

There are also numerous cases where people with ideal BMI measurements are suffering from diseases associated with overweight and obese people.

Another valuable argument against BMI is its generalized result. The body weight is closely related to bones, muscle mass, fat, and water content in the body.

There are so many who weigh higher because of the large bone structure and heavy macular build-up.

Just, for example, a well-built and muscular athlete cannot be negatively categorized as overweight or obese because of the higher body weight.

However, BMI could be a good indicator of the health conditions of most adults who follow a common generic lifestyle.

BMI is not able to exactly pinpoint the amount of fat in the body and the location of the fat.

Mass, fat storage in different parts of the body does not have an equal amount of health hazards associated with it.

The belly fat is more dangerous than the fat on the hips.

Some argue that it is better to assess the fat in the body by measuring the waist circumferences in proportion to the height of the person.

Lastly, if you are not an athlete, an older adult, or a teenager, then BMI could certainly give you some basic understanding of the healthiness of your body and about body weight. BMI is only an indicator and not a reliable predictor of your health conditions.