The Body Mass Index - BMI for short - indicates the ratio of body weight to height. It is an indication of normal weight or whether a person is underweight or overweight. This definition is based on the WHO standard values. It is calculated using the BMI formula: BMI = weight (kg) / height² (m).


BMI calculator - Woman


BMI calculator - Man


BMI calculator - Child


BMI calculator -


All information is without guarantee

Use calculator:

  • Choose whether you want to calculate the Body Mass Index for women, men, children or babies.
  • Enter your weight in kilograms.
  • Enter your height in centimeters.
  • Enter your age in years.
  • Click on

BMI table for women

ageNormal weight
19 to 24 years19 to 24
25 to 34 years20 to 25
35 to 44 years21 to 26
45 to 54 years22 to 27
55 to 64 years23 to 28
Older than 64 years24 to 29

BMI table for men

ageNormal weight
19 to 24 years19 to 24
25 to 34 years20 to 25
35 to 44 years21 to 26
45 to 54 years22 to 27
55 to 64 years23 to 28
Older than 64 years24 to 29

BMI table for children

Children's ageNormal weight (girls)Normal weight (boys)
8 years13 to 1914 to 19
9 years14 to 2014 to 19.5
10 years14 to 20.514.5 to 21.5
11 years14.5 to 20.514.5 to 21
12 years15.5 to 21.515 to 22
13 years16 to 2216 to 21.5
14 years17 to 2316.5 to 22.5
15 years17.5 to 2318 to 23
16 years18 to 2318.5 to 23.5
17 years18 to 23.518.5 to 24
18 years18.5 to 23.518.5 to 24

BMI table for babies

Baby ageBMI (normal weight)
12 months15.6 to 18.2
13 months15.5 to 18.0
14 months15.4 to 17.9
15 months15.3 to 17.8
16 months15.2 to 17.7
17 months15.1 to 17.5
18 months15.0 to 17.4
19 months14.9 to 17.3
20 months14.9 to 17.3
21 months14.8 to 17.2
22 months14.7 to 17.1
23 months14.7 to 17.0
24 months14.6 to 17.0

BMI classification

The World Health Organization (WHO) has drawn up a classification for the Body Mass Index or ideal weight.

The value of the index is thus divided into six categories:

  • under 18.5: underweight
  • 18.5 to 24.9: normal weight
  • 25 to 29.9: overweight
  • 30 to 34.9: Obesity grade I (obesity)
  • 35 to 39.9: Obesity grade II
  • 40 and over: obesity grade III

The tables for normal weight per gender and age can be found in the respective calculator.

The body mass index, also known as body mass index or BMI, clarifies whether your body weight corresponds to your height. From this it can be deduced whether the body weight should be reduced for health reasons.

BMI calculation

The BMI is calculated as follows: Body weight in kilograms divided by height squared.

This results in the following guide values:

  • 18.5 - 24.9 Normal weight
  • 25 - 29.9 Overweight
  • over 30 obesity

The World Health Organization (WHO) has divided the BMI values into different classes, resulting in different tables. Age and gender also play a role here. Both genetically and hormonally, men have a larger amount of muscle than women, so the sexes are also considered separately in the table. These tables with guide values are for adults, as the body composition changes for children due to growth, they are not listed, or the values are determined by the pediatrician in a different way.

For example, the BMI value does not take into account the distribution of body fat or muscle mass. An athlete with a lot of muscle mass, for example, can have the same BMI as people with a lack of exercise and little muscle and a lot of body fat. So the BMI value of a bodybuilder can be the same as that of an obese person with a lack of exercise.

To summarize: The Body Mass Index is intended to monitor the normal weight of an adult in order to prevent obesity and consequently dangerous medical conditions or complications, including

Disease patterns associated with obesity

The following conditions can arise in connection with obesity:

Back pain

Obesity can lead to back pain due to a lot of weight on the back and joints, which can cause increased wear and tear and restricted movement.

Cardiovascular diseases

An unbalanced and unhealthy diet consisting of saturated fats and high-calorie foods plays a particularly important role in cardiovascular diseases. As a result, the blood vessels become calcified and the risk of a heart attack increases.


Type 2 diabetes is also associated with obesity. The body can no longer produce insulin itself and it must therefore be supplied artificially. People with type 2 diabetes have to calculate the exact contents and quantities of all meals in order to supply the sick body with the right amount of insulin. This is very demanding and complicated.


The risk of a stroke can increase with obesity. The risk increases due to circulatory disorders, similar to heart attacks.

Further information can be found online here:


Health problems can be prevented and/or reduced with a healthy diet, plenty of exercise such as fitness training or walks and calculations or sporadic measurements of BMI values either on special scales or with the help of a trainer in a fitness center.


Calculator | Table

On this website, calculations, formulas and sample calculations with simple explanations are provided online free of charge by the author.