BMI Calculator: Calculate Your Body Mass Index (BMI)

What is the BMI?

The full form of BMI is Body Mass Index. Body mass index ( BMI ) is a calculation method developed to help us understand whether we are at a healthy weight for our height.

Body mass index (BMI ) can be used as a screening tool, but is not intended to determine the proportion of body fat in an individual. It is just a method of getting a general idea about whether the person is underweight, fat, obese, or not at ideal weight.

How is BMI calculated?

In a very basic way, the BMI can help us to know the thinness or corpulence that a person can have. For this, it will be necessary to have two main data: your height and your weight. Starting from this information and applying a simple calculation, the person can be classified as normal, underweight or overweight; as well as identifying if there is any health risk.

Although this calculation may vary depending on some aspects, such as the age of the person, their gender and the geographical region to which they belong, a BMI formula that has been accepted by many doctors to determine this information in adults is the following:

The imperial BMI formula = Weight (LBS) x 703 ÷ Height (Inches²)
The metric BMI formula = Weight (KG) ÷ Height (Metres²)

For example
If you are 175cm (1.75m) in height and 75kg in weight, you can calculate your BMI as follows:

BMI = weight (kg) / height (m)2

BMI = 75kg / (1.75m²) = 24.49kg/m²

However, we must be aware that it is not exact and unique data to conclude that a person is or is not healthy in terms of physical complexion. It must be taken into account that an athlete, for example, depending on the discipline he practices, could have a higher or lower BMI, without this implying a health risk. This is because your muscles increase in volume to adapt to the demands of your physical activity, making you heavier than a person with a considerable amount of body fat.

Similarly, a person with a bone density higher than average could have a BMI with a tendency to be in the obesity range, without actually being a health risk.

BMI Calculator

Body Mass Index Charts

After performing the personal calculation of the BMI, the doubt may arise. The result I get, how do I interpret it?

This is a totally valid question because by observing only some digits we cannot deduce anything if we do not compare it with some other reference value. To give you a better idea, the most appropriate thing is to resort to the BMI tables, where we find some ranges so that you can identify where your result is located. Just like our BMI calculator does automatically for your convenience. In this way, you will be able to know if your weight is considered adequate or not according to the agreement of the world health organization.

General table of BMI (Body Mass Index)
DescriptionBMI (Body Mass Index)
Severe malnutrition<16
Moderate malnutrition16.1 – 18.4
Underweight18.5 – 22
Normal weight22.1 – 24.9
Overweight25 – 29.9
Type I obesity30 – 34.9
Type II obesity35 – 39.9
Type III obesity> 40


Although the general table can be helpful, as we have mentioned, the BMI is affected by the gender of the person. Remember that women naturally have an accumulation of fat in areas such as the chest and hips, which are part of their natural anatomy. For this reason, it is considered better to use the corresponding table of BMI. In this case we show the one that has been used in the Spanish Society for the Study of Obesity (SEEDO).

Under weightless than 20
Normal weight20 – 23.9
Mild obesity24 – 28.9
Severe obesity29 – 37
Very severe obesitygreater than 37


Below we can see the values ​​in the table for men.

Underweightless than 20
Normal weight20 – 24.9
Mild obesity25 – 29.9
Severe obesity39 – 40
Very severe obesityover 40

BMI in children

In case you want to determine the BMI for children, we must note that, although there is a general table, to study the data in a more precise way this method is not ideal.

Let us remember that in the first months infants can increase in height and weight rapidly, then they have periods of stability that alternate with others of accelerated growth and these may be different in each child. In addition, gender is also a factor that makes a big difference.

In these cases, what doctors usually use is a percentile method, where the height and weight of the child are compared against the statistic determined by health organizations, to deduce if their development is adequate.

Overweight Risks

Exposing the human body to excess body fat has clear health consequences that cannot be ignored. These problems are associated, among m

any other things, with the decrease in life expectancy, causing numerous deaths at an early age. For this reason, health organizations in each country are increasingly concerned about the high body mass indices in the general population, because they are related to various implications that affect people’s daily performance.

If we analyze from the simplest risks, we can notice are the body pain, mainly in the legs. Well, it is the part of the body that will bear all the weight when standing and walking. We can also mention the discomfort or even inability to perform simple daily tasks such as getting dressed, carrying out adequate personal hygiene and moving from one place to another if that implies a considerable effort.

It can also be commonly associated with impaired heart function, as the heart has to work harder to provide blood supply to every corner. For this reason, the blood pressure in the arteries increases causing gradual damage to vital organs such as the kidneys, liver, gallbladder, etc.

At the same time, the mobility of the individual is hindered, which leads to a lower daily caloric intake, which creates the ideal conditions for the overweight index to continue to increase little by little over time.

But this is not all, a person who is overweight also faces other health problems related to their mood. Your self-esteem can deteriorate to levels of depression and anxiety, which aggravate health problems and can lead you to eat nervously or abuse medications designed for weight control.

Severe Thinness Risks

In the ranges established for the body mass index, the extreme opposite to being overweight is not healthy either, since it is associated with poor assimilation of nutrients, a consequence of various problems that can be attributed to an inadequate diet or internal disorders of the body.

In very broad terms, the body cannot maintain the volume considered healthy for its organs and aggregates, for this reason, it will be forced to conserve its energy to perform the most essential functions, such as: maintaining brain function, making the heart can and digestion takes place. In addition, the longer this problem exists, as with obesity, the more severe and irreversible the health effects will be.

Among the most common health problems that are related to a low BMI is the general weakness of the person, which leads them to experience exhaustion even without having done any physical activity. In children, it can slow growth and development, while in adolescents it can prevent sexual maturation from taking place normally.

Likewise, in adult women it can interfere with fertility cycles, preventing pregnancy from being achieved, or it can be the cause of spontaneous abortion since the body does not consider the gestation process as a priority activity and classifies it as a vital risk.

Bone fractures are also common in people with a low body mass index, as the bone structure is also weakened very often. This is because, in the event of a low supply or assimilation of calcium, the body will take it from this source.

In addition, those who suffer from this problem will have a greater chance of presenting severe symptoms in simple infectious diseases, because their immune system cannot fight the agent that is attacking it.

As we can conclude, it is always appropriate to observe our BMI from time to time to detect any variation that represents a risk. This will make it easier to attend to it in a timely manner before it becomes a health problem.

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