This calculator can be used to calculate a person´s body mass index and its corresponding weight range according to the World Health Organization classification or the classification of Centers for Disease Control and Preventions.
The body mass index (BMI) or Quetelet index is a simple index based on weight and height that can be used to classify low weight, overweight and obesity. It´s a measure of an individual´s fat.
 The BMI
 It can be defined as the weight of a person in kilograms divided by the square of its height in meters (kg / m2).
 It can be used as an indicator of disease risk; The higher your BMI, the higher your risk of certain diseases, such as heart disease, high blood pressure, diabetes, gallstones, respiratory problems and certain cancers.
 This measure is only an estimate that does not take into account age, physical activity or sex.
 The weight category
 In adults, the weight category is evaluated by comparing the BMI with certain fixed thresholds.
 In children and adolescents, the weight category is evaluated by comparing the BMI with certain statistical values (percentiles or zscore) for children of the same sex and age.
 WHO weight categories:
 Adults:
Category  IMC 

Thin (extreme)  <16 
Thin (moderate)  1617 
Thin (light)  1718,5 
Normal  18,525 
Overweight  2530 
Obese (class I)  3035 
Obese (class II)  3540 
Obese (class III)  >40 

 Children and adolescents between 5 and 19 years old.
Category  IMC s / age 

Thin (extreme)  <3SD 
Thin  <2SD 
Overweight  >+1SD 
Obese  >+2SD 
* BMI by age greater than 2 standard deviations above the median WHO growth reference.
 CNC weight categories:
 Adults: the same as OMS.
 Children and adolescents between 2 and 20 years old.
Category  Percentile 

Thin  <5% 
Normal  5%85% 
Overweight  85%95% 
Obese  >95% 