A person’s weight in kilograms divided by their height in meters is known as their BMI. It is a low-cost, simple-to-use approach of identifying people who may be at risk for health concerns due to their weight.

The term “BMI-for-age” refers to the BMI calculation for children and adolescents that takes into account both their chronological age and their gender. Obesity and other health problems can occur in youngsters who have an excessive amount of body fat. A person’s health can also be jeopardized if they are underweight.

A high body mass index (BMI) may be a sign of excessive body fat. It is not possible to directly quantify body fat using the BMI, although other measures of body fat are strongly connected with the BMI.

## How is a child’s BMI calculated?

The procedures for calculating BMI using the BMI Percentile Calculator are as follows:

- Calculate your height and weight. For more information, see Measuring Children’s Height and Weight Accurately At Home.

- To determine BMI, use the Child and Teen BMI Calculator. Standard formulas are used to compute the BMI.

## What Is a BMI Percentile, and How Does It Affect Your Health?

After the BMI for children and teenagers is calculated, it is expressed as a percentile using either a graph or the percentile calculator given below. These percentiles represent a child’s BMI in comparison to US youngsters who took part in national surveys between 1963 and 1994. Weight and height, as well as their relationship to body fatness, alter as people grow and develop. As a result, a child’s BMI must be compared to other children of the same gender and age.

The BMI-for-age percentile growth charts are the most widely used indicator in the United States for determining the size and growth trends of children and teenagers. Expert committee suggestions were used to create BMI-for-age weight status groups and percentiles, as shown in the table below.

Weight Status Category | Percentile Range |
---|---|

Underweight | Less than the 5^{th} percentile |

Healthy Weight | 5^{th} percentile to less than the 85^{th} percentile |

Overweight | 85^{th} to less than the 95^{th} percentile |

Obesity | Equal to or greater than the 95^{th} percentile |

The following is an example of how a 10-year-old boy’s BMI values may be interpreted:

## How is BMI used with children?

BMI is not a diagnostic tool for children and teenagers. Instead, it’s utilized to check for possible weight and health problems. If a child’s BMI is high for his or her age and gender, a health care provider may do additional tests to evaluate if extra fat is an issue. Skinfold thickness measurements, dietary and physical activity evaluations, family history, and other appropriate health exams are examples of these assessments. Beginning at the age of two, the American Academy of Pediatrics recommends using BMI to screen for overweight and obesity in children. Consult the World Health Organization (WHO) guidelines for children under the age of two.

## How can I tell if my child is overweight or has obesity?

Children and adolescents ages 2 to 19 should be screened for obesity and overweight using BMI, according to the CDC and AAP. Consult the WHO criteria for children under the age of 2 years old. As a screening measure for overweight and obesity in children and teenagers, body mass index (BMI) is not diagnostic. A more thorough evaluation by a medical specialist is required to identify whether or not the youngster has an excessive amount of body fat.