The same number on the scale can have different meanings. 80 kg with a height of 190 cm is the norm. But the same 80 kg at 160 cm is already too much, especially for a woman. So focusing on kilograms alone is not enough. Ideally, a person's height, gender, age and lifestyle should be taken into account. In this regard, to determine the norm and pathologies, they use such a concept as BMI.
What is it
BMI is an abbreviation for body mass index. In English it sounds like Body Mass Index (BMI). This is a parameter that reflects the degree to which a person’s weight and height correspond. Allows you to objectively assess whether he has extra pounds, whether he is suffering from exhaustion, or whether everything is normal. Most often used in two cases.
Secondly, calculating BMI is necessary in order to control your figure, correct it and, if it deviates from the norm, take appropriate measures.
Generally accepted formula
Now the BMI formula is officially used, developed in the middle of the 19th century by Adolphe Quetelet, a sociologist and statistician from Belgium. It takes into account only two parameters - height and weight, which does not make it ideal for identifying excess or missing kilograms. And yet, for many decades it has been used in medicine.
The Quetelet calculation formula looks like this:
- m (weight) = 80 kg;
- h (height) = 1.6 m;
- square meters: 1.6 x 1.6 = 2.56;
- I = 80 / 2.56 = 31.25.
This completes the calculation of the body mass index: it is equal to 31.25. We remember this figure and compare it with normal indicators, according to the table below.
Norm and deviations
On the official WHO website there is a special table that shows both the BMI norm and deviations. Using it, we look for which category we fell into with our I = 31.25.
We did not fall into the normal body mass index, and the table no longer shows just extra pounds, but class I obesity (an overview of obesity classifications can be found).
So calculating BMI and comparing the data obtained with the norm is not at all difficult. The problem is that the formula is already outdated, and the WHO table does not reflect all factors. This means that the results may not be entirely correct.
For adults
Since weight is influenced by gender and age factors, tables have appeared in which you can see the norm and deviations from it separately for women and men, and even taking into account age. As experts note, here the data is more accurate and correct.
For men based on age
For women, taking into account age
Depends only on gender
Depends only on age
Anything below normal is underweight. This means that you urgently need to gain the missing kilograms. If the result exceeds the parameter indicated in the table by 5 units, you have overweight. If the difference is more than 5, you should seek qualified help, since we are most likely talking about.
For children
To calculate BMI for children, you will need the same formula, but the table, accordingly, will be different. In a child, metabolic processes proceed much faster, and energy costs are several times higher than in adults. Therefore, it is imperative to use other standards.
For boys
For girls
The jumps from 7 to 9 years are explained by the body’s preparation for adolescence and puberty.
Regular determination of a child’s BMI allows parents to control his weight and promptly prevent both exhaustion and the appearance of extra pounds(read about the characteristics of childhood obesity).
Ideal weight calculation
Find out your ideal mass bodies can be calculated using various formulas that use different parameters for calculations.
General designation (R - height):
- Bornhart index: R in centimeters x (multiply) by chest circumference in centimeters / (divide) by 240;
- Breitman index: R in centimeters x 0.7 - 50 kg;
- Broca–Bruksht index: for women R in centimeters – 100 – (R in centimeters – 100) / 10; for men R in centimeters – 100 – (R in centimeters – 100) / 20;
- Davenport index: weight in grams / R in centimeters squared;
- Korovin index: you need to measure the thickness of the skin fold near the 3rd rib (normal 1-1.5 cm) and at the level of the navel (normal 1.5-2 cm);
- Noorden index: R in centimeters x 420 / 1,000;
- Tatonya index: R in centimeters - (100 + (R in centimeters - 100) / 20).
There is also a small addition to the Broca-Bruckst formula: after the result obtained, you need to measure the volume of the wrist, and if it is less than 15 cm, subtract 10% from the ideal weight; at 15–18 cm we do not change anything, if more than 18, we increase ideal weight, obtained according to the formula, by 10%.
Using any formula, calculating your ideal body weight is easy. The main thing is to draw objective conclusions after comparing the results obtained with real numbers. If the difference in both directions (more/less) is more than 5 kg, then there are problems that are better to start solving immediately.
Important note!
We draw your attention to the fact that in different sources, data on the norm and deviations of BMI for men, women and children, taking into account age, may differ quite noticeably with the exception general table recommended by WHO. The fact is that the parameters are calculated according to different methods and formulas - this is where the difference within one comes from. In this regard, all parents are recommended to use the data for children only as a guide and, in case of doubt, be sure to consult a pediatrician without taking any independent measures.
Thanks to propaganda healthy image In life, many of us think about the ideal balance between weight and height. Helps resolve this issue special formula. The body mass index calculated from it, although it does not give a complete picture, still allows one to determine: is obesity occurring?
What is BMI (body mass index)?
This concept was introduced into use by the Belgian sociologist and statistician Adolphe Quetelet. BMI or BMI (in English the wording sounds like “body mass index”) is a value that allows you to correlate a person’s weight with his height and understand how they correspond to each other: is the weight normal, or is it below (above) the optimal level . BMI helps doctors decide whether a patient needs weight adjustment.
BMI calculator
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// Function for calculating the mass index
//Start function Calculation
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{
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$index_mass=substr($index_mass, 0, 5);
?>
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?>
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}
//End function Calculation
if (!empty($_POST[‘calculation’]))
{
if(!$height)
$info ='
Enter your height.
if(!$weight)
$info = '
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if(count($info) == 0)
{
calculation($height, $weight);
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}
echo implode($info);
Formula for calculating BMI
BMI is calculated extremely simply: body weight, expressed in kilograms, must be divided by height, expressed in meters and raised to the second power (BMI is measured in kg/m?).
As an example, let's calculate the BMI for a person weighing 90 kg and height 165 cm:
90 kg/1.65x1.65= 31.22
The calculated indicator indicates the presence of the first stage of obesity (this can be understood by studying the table below).
Interpretation of BMI indicators
BMI Explanation
Up to 16 kg/m? Severe underweight
From 16 to 18.5 kg/m? Underweight
From 18.5 to 25 kg/m? Normal body weight
From 25 to 30 kg/m? Pre-obesity condition (overweight)
From 30 to 35 kg/m? First stage of obesity
From 35 to 40 kg/m? Second stage of obesity
From 40 kg/m? and above Third stage of obesity
Don’t be upset if the table categorizes you as, to put it mildly, overweight people. Thus, according to a study by Israeli scientists, men with a BMI equal to 25-27 kg/m2 (the concept corresponds to the presence of excess weight) live longer than thinner or fuller representatives of the stronger half of humanity.
How relevant is BMI?
It's worth remembering that
BMI
does not always correctly reflect the state of affairs. Men who have significant muscle mass can be classified as obese. Meanwhile, their fat tissue content is often lower than usual.
Race also matters. So, in 2000, WHO decided to reduce the obesity threshold for representatives of the Mongoloid races by 5 units (to 25 kg/m?). At the same time, researchers propose raising the obesity threshold for representatives of the Negroid race and for Polynesians (up to 32 kg/m?). To avoid mistakes, experts recommend simultaneously determining the central obesity index. You can also use the body volume index.
To determine optimal body weight, a number of other indices are used:
1. For people whose height ranges from 155 cm to 170 cm, the Broca index is ideal (this formula, by the way, is most often used in clinical practice). The formula looks like this: height in centimeters, subtract 100 and subtract 10-15%.
2. The Bornhardt index is suitable for athletes (it is calculated taking into account chest volume). The formula takes the following form: multiply height in centimeters by chest circumference and divide by 240.
3. The Davenport index is of interest. Weight expressed in grams must be divided by height squared, expressed in centimeters (if the resulting index is more than 3, then this indicates the presence of obesity).
What is central obesity?
Central obesity is excessive deposition of adipose tissue in the abdominal area. It is determined by the ratio of waist and hips. For women, the indicator should not exceed 0.9, and for men - one. An overhanging belly increases the risk of cardiovascular diseases and contributes to changes in blood sugar levels (higher risk of developing diabetes). This is why it is so important to use the formula for calculating central obesity when determining body mass index.
Currently, body mass index is increasingly criticized. According to calculations, an elderly person with a pronounced tummy, but no muscle mass, may have a minimum BMI, and a bodybuilder will be considered a person suffering from the third stage of obesity. You should not completely and completely trust formulas and calculations - everything is too individual.
BMI is an abbreviation of the term Body Mass Index in English, which translates as “ body mass index". BMI is a ratio of body weight to height, which determines whether a person is underweight, normal or overweight.
BMI is one of the important methods for determining physical condition, but, unfortunately, it is not always enough. An important addition to body mass index is measuring the amount of abdominal fat—too much can mean dangerous abdominal obesity, even with a normal BMI. In addition, as counterintuitive as it may sound, research shows that people with a slightly elevated index tend to be healthier and live longer than those who are in the normal range (have a “normal weight”). There are even suggestions that the WHO threshold for overweight (25) may be too low.
BMI calculation
The formula is very simple:
BMI = body weight in kilograms divided by height in meters squared.
For example, for a person with a height of 1.82 m and a weight of 76 kg, the BMI will be:
76 kg: (1.82 m)² = 76: (1.82 x 1.82) = 22.9
Using the Body Mass Index calculator, you can easily determine the amount of fat in your body. Just enter your height in centimeters and weight in kilograms.
BMI calculator online
Table characterizing body mass index indicators
Ideal body mass index (BMI)
Taking into account the difference in muscle mass between the average man and woman (we do not take athletes into account), the best indicator is considered to be:
- 20-22 for women;
- 23-25 for men.
The body mass index coefficient (number) for men and women is the same, but the program interprets the result differently - you receive a calculation depending on your gender.
For example, a man with a BMI of 18 or higher has nothing to worry about, but women should not drop their weight to a BMI of 19 or lower. So the program will tell a man with a BMI of 18.5 that everything is fine, and a girl with the same body mass index will indicate that she is underweight.
BMI - 18 or less
If you are clearly not eating enough, then you should normalize your diet as soon as possible.
Do you feel like you're eating enough? Then you need to visit a doctor as soon as possible and undergo an examination in order to exclude dangerous diseases.
A body mass index of less than 16 is more dangerous to health than 30+.
BMI - 25 or more
Don't be upset or worried about having a high body mass index. This indicator is very average and is not suitable for everyone. Children and athletes should not rely on it at all.
It's another matter if the imperfections of your figure are visible to the naked eye. Before starting a diet, you should definitely consult your doctor. Tests may be needed to make sure your excess weight is not due to a medical condition.
And only after making sure that there are no contraindications can you begin to lose weight.
For those who do not have time to visit a doctor, we can advise you to minimize the consumption of salty, fried and fatty foods, and also start doing simple exercises. This alone will seriously reduce the risk of developing cardiovascular diseases and significantly improve the overall condition of the body.
How is body mass index calculated?
You can do this yourself. A regular calculator will simplify this task. Double divide your weight in kilograms by your height in meters.
Example for a person 180 cm tall and weighing 75 kg.
- Height 180cm is equal to 1 meter and 80 centimeters, that is, 180cm = 1.8m.
- 75/1,8 = 41,6
- 41,6/1,8 = 23,1
- Body mass index is 23,1
Body mass index and the army
Height less than 150 centimeters or body weight less than 45 kg grants a conscript a one-year deferment. If, after examination and/or treatment, body weight does not increase, then such a man is exempt from conscription.
The right to defer for half a year is granted to conscripts with a body mass ratio of less than 18.5 (aged 18-25 years) and below 19 (for men over 25 years old).
Ideal weight according to Kreff's formula
Calculates your ideal weight based on your age and body type. It is an improved version of the Broca index.
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 basis for the concept of BMI was 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:
Index | Description | Life risk level | ||
|---|---|---|---|---|
| Up to 25 years | Over 25 years old | |||
| Being underweight may indicate a poor diet, an eating disorder, or another health problem | High. It is possible that anemia may develop, bone loss may occur, and in women, problems with conception may occur. The functioning of the immune system deteriorates, the body does not fight infections | You should forget about restrictions on food intake, improve the quality of your diet, and also eliminate stress and physical activity, that is, the body should receive more calories than it expends | ||
| Up to 22.9 | From 20 to 25.9 | Norm | Absent, provided that the waist circumference does not exceed 80 cm for women and 94 cm for men | To maintain indicators within normal limits, it is enough to maintain the same dietary regimen and do not forget about daily warm-up (walking, cycling, exercises) |
| 23-27,4 | 26-27,9 | Overweight | Elevated, possible development of metabolic syndrome | It is necessary to balance your diet by excluding high-calorie and fatty foods, and it is also recommended to radically change your lifestyle - devote sufficient time to sports, proper sleep and active pastime |
| 27,5-30 | 28-31 | Obesity (1st degree) | Very tall. There is a risk of developing type 2 diabetes, as well as the formation of malignant tumors | A specialist consultation is required, as well as a full examination of the body, including diagnosis of the thyroid gland, heart and blood vessels |
| 31-35 | 32-35,9 | Obesity (2nd degree) | ||
| 35,1-40 | 36-40,9 | Obesity (3rd degree) | ||
| ≤40,1 | ≤41 | Obesity (4th degree) | ||
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.
