Calculation of BMI taking into account age and gender. How to calculate your normal weight: BMI will help

Body mass index has become especially relevant in Western countries, where the problem of obesity has become quite acute. At the very beginning, the BMI calculation was developed for sociological research, so making a medical diagnosis using these calculations is not entirely correct.
However, the accessibility and ease of calculation made this calculator very popular among the population. If the index exceeds the number 30, then this most likely indicates obesity.
It is important to understand that body mass index is not useful for making a diagnosis, but it can help as a guide when trying a new fitness program or diet.
The BMI calculator will determine the starting point and allow you to track changes in body weight.

Formula for calculating body mass index (BMI)

In order to find out your BMI, you only need to divide your weight in kilograms by the square of your height in meters.

BMI = WEIGHT / HEIGHT 2

The formula does not take into account the gender and age of the person, despite the fact that the BMI of men is higher than the BMI of women, and the BMI is higher in middle-aged people, and in children and the elderly this figure is lower.

Summary table of values

Interpretation of BMI indicators, in accordance with the recommendations of the World Health Organization (WHO)

Keeping your body in shape is a key point in preventing heart and vascular diseases. Calculating your body mass index (BMI) is one way to check your healthy weight. This indicator will show how much weight corresponds to a person’s height, and whether such a proportion poses a threat to life.

The basics of the concept of BMI were developed by the Belgian scientist Adolf Quetelet, but the term itself was first coined after the publication of an article on obesity in the Journal of Chronic Diseases in 1972.

This index was created to determine the amount of fat, muscle and bone mass in each individual in order to further classify his weight as underweight, normal or overweight.

BMI (from the English “body mass index”) has a direct relationship with the normal functioning of the whole organism. Because being overweight increases your risk of developing diseases such as:

• ischemic disease;
• type 2 diabetes;
• hypotension;

How to calculate your BMI?

The Quetelet index, better known as the body mass index, is a value determined by the formula: a person’s weight divided by his height in square meters.

For example, for a girl weighing 65 kg and whose height is 172 cm, the calculation will be made as follows: 65/(1.72) 2 = 21.97. According to table No. 1, it can be determined that this indicator is within the normal range.

To simplify the calculation, you can use special online calculators that independently calculate body weight according to specified parameters.

If you use pounds and inches to calculate BMI, the formula is: weight (pounds)/height (inches squared)*703.

More information on how to calculate the mass index and decipher the results obtained can be seen in this video:

Decoding data: BMI table

According to the generally accepted classification, the Quetelet index has the following ranges:

According to studies by American scientists, 1% of men and 2.5% of women suffer from underweight. At the same time, the maximum life expectancy is observed in guys whose BMI is 25-27 kg/m2.

BMI: what to pay attention to?

It should be remembered that calculating the mass index is not the basis for making a diagnosis. For some people, particularly athletes, their BMI can be misleadingly high compared to their actual body fat levels.

For example, the ideal weight for a girl 175 cm tall is 75 kg. But, if she has a thin physique, her norm should be calculated according to the following scheme: 75 kg-10% = 68 kg. Conversely, obese people should add 10% to their current weight.

The World Health Organization does not take into account a person's age and gender when calculating BMI. For children over 2 years old, the index is calculated according to the same scheme as for adults.

Studies conducted by British scientists have proven that the BMI of girls 12-16 years old is, on average, 1 kg/m2 less than the BMI of boys of the same age category.

Also, when calculating the mass index, the principle of distribution of fat deposits in the body is not taken into account. That is, the indicators may be overestimated due to the accumulation of fat in the lower part of the body, which, in principle, is not life-threatening. And at the same time, a person with a normal index should be more concerned about health if excess fat is based in the abdominal area.

In matters related to obesity, in addition to BMI, it is necessary to consider:

Application of BMI in the world

In 2005, Singapore found that the percentage of fat in Asians is relatively higher than that of Europeans, as a result of which the former are more likely to suffer from diabetes and cardiovascular diseases.

Recently, the authorities of France, Italy, Israel and some other countries made changes to the legislation, according to which models with an index below 18 are not eligible to participate in fashion shows. In this way, a healthy lifestyle is popularized and anorexia is prevented among young people.

According to the laws of the Russian Federation, if a conscript’s Quetelet index deviates from the stipulated standards (both up and down), he has the right to receive a deferment from military service for up to six months. During this period, the conscript is required to undergo examination and bring the indicators back to normal. For comparison, in Taiwan, conscripts with a low or high BMI are immediately disqualified.

Calculation of excess weight using BMI

Using BMI, it is easy to calculate excess weight; to do this, it is enough to correct the already known formula as follows:

Weight (kg) – normal BMI (see table) * height (m 2)

For example, for a man under 25 years old and weighing 115 kg, the normal BMI indicator will be the number 22. That is, his excess weight is: 115-22 * (1.75 2) = 47.6 kg

This formula shows that normal weight in this case should not exceed 67 kg.

So, body mass index is an important indicator designed to monitor the weight and health of each person. Despite some inaccuracy, BMI has been used in world practice for many decades for the primary diagnosis of obesity in patients of all age groups.

14,103 Views

Our online Quetelet body mass index calculator allows you to determine for free the weight according to the height of an adult. BMI shows how much mass 1 meter of body area contains. The calculation formula was developed by the Belgian sociologist Adolphe Quetelet in 1869.

"var message7="

Obesity 3 degrees. Excess weight threatens your life, consult a doctor. Use diets and other methods of weight loss only under the supervision of a specialist.

" // END message output

ENTER YOUR DETAILS

• Calculate

YOUR BODY MASS INDEX

(BMI) shows whether your weight is medically normal.

The BMI indicator is used by the World Health Organization to roughly estimate the normal body weight of a person. There are no exact criteria.

This value does not take into account the characteristics of age categories, so calculating BMI is only suitable for non-growing people 17-60 years old.

And in some cases, assessing physique using Quetelet’s formula is useless. For example, the body mass index of a professional athlete will be higher than normal due to developed muscles.

To verify the presence of excess weight, a body mass index calculator is carried out simultaneously with an online calculator.

How to find out the mass index

Body mass index can be calculated independently using the formula. When evaluating the results, remember that these characteristics are approximate and do not constitute a medical diagnosis. If your BMI differs from the norm, do not rush to condemn yourself as “obese” or “.”

Discuss concerns about excess weight with your dietitian. Age, gender and lifestyle influence the predominance of fat or muscle in the body. It is likely that the result obtained is the norm for you.

Calculation of BMI using the formula is designed taking into account a person’s weight and height: BMI = Weight kg/height m2

In addition to Quetelet’s formula, you can determine whether body weight corresponds to the norm using other indices:

• You can calculate Broca's Index with a height of 155 to 170 cm. The calculation is made using the formula: (height (cm) – 100) ± 10%.
• Calculation of weight norms according to the Breitman index: height (cm) multiplied by 0.7 - 50 kg.
• The Bernhard index is calculated as follows: height (cm) multiplied by chest circumference (cm) and divided by 240.
• The Davenport index can be calculated using the formula: mass (g)/height (cm2). A high result (more than 3.0) means the presence of excess weight.
• Calculation of the Oder index: multiply the distance from the parietal zone to the symphysis (cm) by 2 - 100.
• You can find the value of the Noorden index using the formula: height (cm) multiplied by 420 divided by 1000.
• Calculation of the Tatonya index: height (cm) – (100+(height (cm)-100)/20).

How to calculate BMI results

When you calculate the index and get the result, compare it with the indicators in the table.

Calculating BMI is conventionally divided into 3 ranges: underweight, normal and overweight, each of which includes several stages of body composition assessment.

• BMI less than 16– severe lack of weight, you need to consult a doctor. Most likely, the doctor will diagnose anorexia and prescribe a course of enhanced nutrition and psychotherapy. Anorexia is an eating disorder that leads to exhaustion of the body and can be fatal.
• BMI less than 18.5– slight lack of weight. You need to eat more and include more fats in your diet. It’s better to contact a nutritionist to draw up a therapeutic program.
• BMI 18.5-24.9– normal weight. Maintain the average value of this range, try not to go beyond the limits, this way you will maintain a slim figure without signs of thinness and obesity.
• BMI 25-29.9– an indicator of excess weight. Obesity is a long way off; body weight can be reduced with exercise and a healthy diet. Eliminate sugar from your diet and move more.
• BMI 30-34.9– . Consult a nutritionist, there is a risk of developing cardiovascular disease, atherosclerosis and diabetes.
• BMI 35-39.9– 2nd degree obesity. Contact a nutritionist, lose weight urgently, the chance of developing diseases associated with excess weight increases by 3 times.
• BMI over 40– 3rd degree obesity. Excess weight threatens your life, consult a doctor. Use diets and other methods of losing weight only under the supervision of a specialist.

BMI tables based on age and gender

Interpretation of the Quetelet mass index is indicative. The calculation results for men and women, children and adolescents need to be adjusted and clarified. Pay attention to the tables for decoding BMI taking into account age and gender.

For women

Body mass index for women can be calculated in a similar way, using Quetelet's formula. But correct interpretation of the results is important; age also affects the result obtained:

• 19 – underweight;
• 20-25 – within normal limits;
• 26-30 – excess;
• 31+ is a sign of obesity.

BMI tables are useless during pregnancy - the result will not correspond to the norm, even if you have an excellent physique.

Men

A too low or high body mass index for men causes a six-month deferment from military service. When examined at the military registration and enlistment office, the correct calculation of BMI will determine the fate of the conscript. What mark will the doctor give - fit or not?

• 18 – underweight;
• 18.5-23.8 – within normal limits;
• 23.9-28.5 – overweight;
• 29+ is a sign of obesity.

For athletes

When calculating the index using the classical formula, they do not take into account that one type of tissue predominates in the body: muscle or fat. An athlete has more muscle mass, so his BMI is always high. Professional athletes use other norm indices.

For example, to calculate body proportions, divide your waist size by your hip size. The male norm is coefficient 1, the female norm is 0.85.

For children and teenagers

Children's bodies grow and change, so the adult BMI formula is not suitable for children. Weight standards for children and adolescents are different. Calculations must be made taking into account the age category and gender of the child.

To determine the BMI of a child or adolescent, centile tables are used.

Centile table for determining BMI in girls under 10 years of age:

Centile table for determining BMI in boys under 10 years of age:

Each column of the centile table shows the normal limits in percentages or centiles. The average value characterizes the normal weight of a healthy child. The normal limits correspond to the range of 25-50-75%. Adjacent intervals respectively mean: 10-25% - below and 75-90% - above the average.

Centile table for determining BMI in teenage girls:

Centile table for determining BMI in teenage boys:

Every modern person needs to know how to calculate body weight and draw correct conclusions about the state of the indices that show whether you have obesity or a predisposition to this disease. We provide you with basic methods on how to calculate your body weight using simple formulas and tables.

Human body weight and its excess

A person’s body weight is the most important indicator of our health, determining whether nutrition meets the body’s needs. A distinction is made between normal, overweight and underweight.

Naturally, obesity necessarily presupposes the presence of excess body weight formed due to the accumulation of fat.

However, the concept of excess body weight is not synonymous with obesity and has an independent meaning. So, many people have a slight excess of body weight that does not reach the level of disease, that is, obesity. In addition, excess body weight is caused by developed muscles (in athletes or people engaged in heavy physical labor) or fluid retention in the body due to a number of diseases.

In the same way, lack of body weight does not always reach the level of disease - protein-energy malnutrition. Many methods have been developed to control body weight. They are usually aimed at comparing height and body weight and comparing the result with standard indicators calculated on the basis of various formulas or given in special tables. Previously, in domestic medicine, body weight that exceeded the norm for a given adult by 5-14% was called excess, and that exceeded the norm by 15% or more indicated obesity as a disease. At the same time, in foreign medical practice, obesity was considered to be excess body weight that reached 20% or more compared to the norms adopted in tables or obtained using calculation formulas. As a result, obesity rates in our country were higher than in other countries.

Broca's formula

Broca's formula, proposed over a century ago by the French surgeon and anatomist Paul Broca, is still famous. According to this formula, the following normal indicators are obtained.

Normal body weight

For men of average build:

• with a height of up to 165 cm, the norm of body weight in kilograms is equal to the height in centimeters minus 100;
• with a height of 166-175 cm - minus 105;
• with a height of 175 cm or more - minus 110.

Fatness or obesity: methods for assessing body weight

Women of the appropriate height and build should have a body weight that is approximately 5% less than men.

A simplified version of the calculation is also proposed:

• for women under the age of 35, normal body weight should be equal to height in centimeters minus 110;
• over 35 years old - height in centimeters minus 100.

In people with a narrow chest (asthenic physique), the obtained data decreases by 5%, and in people with a wide chest (hypersthenic physique) it increases by 5%.

I note that the formula “height in centimeters minus 100,” popular due to its simplicity, and used for people of any height, distorts Broca’s index.

How to determine BMI: calculating body mass index

Currently, a very informative indicator is used in international practice - the calculation of body mass index (BMI), also called the Quetelet index. In 1997 and 2000 WHO recommended assessing body weight based on BMI, which Russian doctors agreed with. However, in the report “Prevention, diagnosis and treatment of primary arterial hypertension in the Russian Federation” (2000), experts from the Scientific Society for the Study of Arterial Hypertension, the All-Russian Scientific Society of Cardiologists and the Interdepartmental Council on Cardiovascular Diseases made an amendment: as the lower limit of BMI, characterizing normal body weight, it is proposed to consider 20 kg/m2 instead of the WHO recommended indicator of 18.5 kg/m2 shown in the table. The reason for this proposal is simple: a number of studies have found that among people with low BMI values ​​(less than 19-20 kg/m2), there is a higher mortality rate not only from cancer or chronic obstructive pulmonary diseases, but also from cardiovascular diseases.

Before determining BMI, existing body weight in kilograms is divided by height in meters squared:

BMI = body weight (in kilograms) / (height in 2 meters).

Body Mass Index Score Chart

The body mass index table allows you to assess your health status and anticipate possible risks of developing chronic diseases. It provides characteristics of body mass index (BMI) indicators. We caution you that body mass index assessment should be carried out by a qualified physician, taking into account your individual characteristics.

I will demonstrate the application of the formula using a specific example. Let's assume your height is 165 cm and your weight is 67 kilograms.

1. Convert height from centimeters to meters - 1.65 m.
2. Square 1.65 m and it becomes 2.72.
3. Now divide 67 (weight) by 2.72. Your result is 25.7 kg/m2, which corresponds to the upper limit of the norm.

You don’t have to calculate BMI individually, but use a special table developed by D. G. Bessenen in 2001.

Please note that it has a number of disadvantages: there are no BMI indicators below 19 kg/m2, and BMI characterizing different degrees of obesity are given in abbreviated form in the table.

Table - Body mass indices according to height and body weight:

Waist hip index

In recent years, it has been found that the risk of developing a number of diseases depends not only on the degree and duration of obesity, but also on the nature of the distribution of fat in the body.

Depending on the location of fat deposits, there are:

• abdominal obesity (also called visceral, android, “upper”, “apple” type, male type) - excess fat is located mainly in the abdomen and upper torso. This type of obesity is more common among men;
• gluteofemoral obesity (also called gluteofemoral, gynoid, “lower”, “pear” type, female type) - excess fat is located mainly on the hips, buttocks and lower torso, which is typical for women.

With abdominal obesity, even minimal excess body weight increases the risk of cardiovascular disease and death from it. The likelihood of coronary disease increases, as well as its three main risk factors: arterial hypertension, type 2 diabetes mellitus and lipid metabolism disorders (increased blood cholesterol and other indicators). The combination of these diseases and conditions is called metabolic syndrome. Its treatment, including with the help of diet therapy, is a task of paramount importance. Moreover, treatment is indicated not only for diagnosed abdominal obesity, but also for significant excess body weight (BMI - 27-29.9 kg/m2), if fat is deposited mainly in the upper part of the body.

Waist hip index- this is the ratio of the waist circumference (measured above the navel) to the largest circumference of the hips (measured at the level of the buttocks).

In contrast, gluteofemoral obesity is not associated with significant additional risk and poses minimal medical consequences. Its treatment is mainly cosmetic. Let me note that we are talking about obesity without concomitant diseases, especially without type 2 diabetes mellitus and arterial hypertension.

To determine the type of obesity, it is necessary to determine the waist/hip index (WHI).

It is permissible to measure only the waist circumference. It is recognized that the risk of developing metabolic syndrome:

• increases moderately with a waist circumference of 80 cm or more in women, 90 cm or more in men;
• increases sharply with a waist circumference of 88 cm or more in women, 102 cm or more in men.

Modern data require new approaches to assessing body weight. In particular, it turned out that underweight is a risk factor for increased mortality from certain non-communicable diseases. The idea of ​​adipose tissue as metabolically inert and exclusively an energy depot has also changed. It has now been established that adipose tissue is a diffuse endocrine gland that produces a number of hormones and biologically active substances

Table - Biologically active substances secreted by adipose tissue:

Leptin and obesity

It is worth mentioning leptin, a hormone produced by fat cells, discovered in 1995. Its level in the blood reflects the energy reserves of adipose tissue, affects appetite, energy consumption and expenditure, and changes the metabolism of fats and glucose. Leptin and obesity are closely related: this substance slows down metabolism, but if there is a deficiency, it can cause a malfunction in the body.

According to the scientific data obtained, only excess body weight that has not reached the level of obesity plays a positive role in the normal functioning of the body.

Lack of fat reserves and leptin deficiency can impair reproductive function in women with sharply reduced body weight, for example, after fasting or with anorexia nervosa, which is often accompanied by amenorrhea. Don't think that science is trying to rehabilitate obesity.

Thus, women with preserved menstrual function and excess body weight have a lower likelihood of developing breast cancer, bone resorption (destruction of bone tissue) and postmenopausal osteoporosis. The negative effect of excess body weight (without obesity) on lipid and carbohydrate metabolism, as well as on blood pressure levels in practically healthy men and women, has not been established. Foreign studies conducted by insurance companies found the lowest mortality rate among people whose body weight exceeded the norm by 10%.

Specialists from the Research Center for Preventive Medicine of the Russian Ministry of Health, who observed men and women aged 40-59 years for 20 years, discovered a dependence of life expectancy on BMI. Thus, 50% of the “thin” and “overweight” subjects died earlier than those who had an average BMI of 20 to 30 kg/m2. At the same time, “thin” men and women died earlier than “overweight” ones. Why this happens and whether people with low body weight have other risk factors is not yet known.

Even more on the topic