Children's Nutrition Research Center

Body Composition Calculators


Software Tools Designed for Public Use 


One important aim of a laboratory in a center such as the Children’s Nutrition Research Center is the dissemination of information to other investigators as well as to the general public. This pertains not only to data produced in the Body Composition Laboratory, but also to ancillary parameters closely related to body composition.

One example of such a measure is body mass index (BMI), a parameter that has come into common use as an anthropometric index of weight status and obesity. Although normative data, such as for BMI, are available and in the public domain, the interpretation of such data is not always intuitive, even to trained professionals.

We have designed and made available, through the Baylor College of Medicine web site, several online tools to allow users to assess Z-scores and percentiles for certain pediatric health measures. These include BMI, height, weight, blood pressure, and various DXA parameters such as bone mineral density and percent fat. The tools use data from normative national references such as NHANES – data that are available but not simple to use. These tools have been and are still being used by many investigators and by the general public.

Body Composition Calculators

Body Mass Index (BMI) and DXA bone density calculators, based on data from the National Health and Nutrition Examination Survey (NHANES), are available to help interpret weight and bone mineral data in children. The Blood Pressure (BP) calculator, based on the childhood BP database to which new NHANES data have been added, can be used to evaluate pediatric hypertension. Please note the DXA and BP calculators are intended for use by medical professionals.

  • Kids' BMI and Growth – Body Mass Index (BMI) is used as a screening tool to identify possible weight problems in children. BMI is calculated from a person's weight and height. Growth curve references for weight and height are available as well. 
  • Pediatric DXA References – Normative references for bone mineral content and density, body fat, and fat-free mass from DXA scans are available (for ages 8 - 20 years). The references are based on age and also on height.
  • Pediatric Blood Pressure – Hypertension (high blood pressure) is an important health issue in children because of its association with obesity. High blood pressure (BP) is considered a risk factor for heart disease and stroke, and high BP in childhood has been linked to high BP in adulthood. This calculator can help to determine whether a child has a healthy BP for his/her height, age and gender. The tool uses the most recent guidelines from the American Academy of Pediatrics (AAP) that incorporate normative pediatric BP tables based on normal-weight children.