BMI is Used Differently with Children Than it is With Adults

In children and teens, body mass index is used to assess underweight, overweight, and risk for overweight. Children’s body fatness changes over the years as they grow. Also, girls and boys differ in their body fatness as they mature. This is why BMI for children, also referred to as BMI-for-age, is gender and age specific.1, 2 BMI-for-age is plotted on gender specific growth charts. These charts are used for children and teens 2 ö 20 years of age. For the 2000 CDC Growth Charts and Additional Information visit CDC’s National Center for Health Statistics.

Each of the CDC BMI-for-age gender specific charts contains a series of curved lines indicating specific percentiles. Healthcare professionals use the following established percentile cutoff points to identify underweight and overweight in children.

Underweight BMI-for-age < 5th percentile
At risk of overweight BMI-for-age 85th percentile
to < 95th percentile
Overweight BMI-for-age 95th percentile


BMI decreases during the preschool years, then increases into adulthood. The percentile curves show this pattern of growth.
What does it mean if my child is in the 60th percentile?The 60th percentile means that compared to children of the same gender and age, 60% have a lower BMI.


Let’s look at the BMI for a boy as he grows. While his BMI changes, he remains at the 95th percentile BMI-for-age.

Age BMI Percentile
2 years 19.3 95th
4 years 17.8 95th
9 years 21.0 95th
13 years 25.1 95th

We see how the boy’s BMI declines during his preschool years and increases as he gets older.

Why is BMI-for-age a useful tool?
BMI-for-Age is used for children and teens because of their rate of growth and development. It is a useful tool because

  • BMI-for-age provides a reference for adolescents that can be used beyond puberty.
  • BMI-for-age in children and adolescents compares well to laboratory measures of body fat.
  • BMI-for-age can be used to track body size throughout life.

For the 2000 CDC Growth Charts and Additional Information visit CDC’S National Center for Health Statistics.

For more information on how to use the growth charts visit The Growth Chart Training Modules.


Hammer LD, Kraemer HC, Wilson DM, Ritter PL, Dornbusch SM. Standardized percentile curves of body-mass index for children and adolescents. American Journal of Disease of Child. 1991; 145:259-263.

Pietrobelli A, Faith MS, Allison DB, Gallagher D, Chiumello G, Heymsfield, SB. Body mass index as a measure of adiposity among children and adolescents: A validation study. Journal of Pediatrics. 1998; 132:204-210.

What is BMI?

Body Mass Index or BMI is a tool for indicating weight status in adults.1 It is a measure of weight for height. For adults over 20 years old, BMI falls into one of these categories:

BMI Weight Status
Below 18.5 Underweight
18.5 – 24.9 Normal
25.0 – 29.9 Overweight
30.0 and Above Obese

Note: BMI for Children and Teens is based on gender and age specific charts.

BMI correlates with body fat. The relation between fatness and BMI differs with age and gender. For example, women are more likely to have a higher percent of body fat than men for the same BMI. On average, older people may have more body fat than younger adults with the same BMI.2

For more information about overweight among adults, see Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Bethesda, MD: NHLBI, 1998.

How does BMI relate to health?

The BMI ranges are based on the effect body weight has on disease and death.3 As BMI increases, the risk for some disease increases. Some common conditions related to overweight and obesity include4

  • Premature death
  • Cardiovascular disease
  • High blood pressure
  • Osteoarthritis
  • Some cancers
  • Diabetes

BMI is only one of many factors used to predict risk for disease. BMI cannot be used to tell a person if he/she has a disease such as diabetes or cancer. It is important to remember that weight is only one factor that is related to disease.

BMI for Adults

  • BMI Formula
  • BMI Calculator
  • What Does This All Mean?
    You have calculated your BMI ÷ now what? This page helps you look at your BMI and find out what it may mean.


Garrow JS and Webster J. Quetelet’s index (W/H2) as a measure of fatness. International Journal of Obesity1985;9:147ö153.

Gallagher D, et al. How useful is BMI for comparison of body fatness across age, sex and ethnic groups? American Journal of Epidemiology 1996;143:228ö239.

World Health Organization. Physical status: The use and interpretation of anthropometry. Geneva, Switzerland: World Health Organization 1995. WHO Technical Report Series.

Calle EE, et al. BMI and mortality in prospective cohort of U.S. adults. New England Journal of Medicine 1999;341:1097ö1105.

BMI: Body Mass Index


The term BMI is often used when discussing the obesity epidemic, but what is BMI?

BMI stands for Body Mass Index. It is a number that shows body weight adjusted for height. BMI can be calculated with simple math using inches and pounds, or meters and kilograms. For adults aged 20 years or older, BMI falls into one of these categories: underweight, normal, overweight, or obese.

Note: BMI for Children and Teens based on gender and age specific charts.

BMI for Adults

  • What is BMI?
    How to determine BMI for adults and how it relates to health.
  • BMI Formula
  • BMI Calculator
  • What Does This All Mean?
    You have calculated your BMI ÷ now what? This page helps you look at your BMI and find out what it may mean.

BMI for Children and Teens
Important information on determining weight status for children and teens (2 ö 20 years) and how BMI is interpreted differently than in adults.

Frequently Asked Questions
Find answers to your questions here.

The Food Guide Pyramid…Your Guide to Food Variety

From A to Z–apricots to zucchini, adzuki beans to ziti–every food fits into the Food Guide Pyramid!

The Pyramid is meant for all healthy people from age two on up. It offers practical advice to enjoy the diverse array of foods available in today’s marketplace.

With its five food groups, the Pyramid has many kinds of foods that promote health. Chosen carefully, all foods can be part of your healthful eating style.

Follow the Pyramid’s advice. You’ll consume the nutrients and energy you need…without too many calories, or too much fat, cholesterol, or sugars.

Enjoy different foods within each food group. Even similar foods differ in their nutrition content. That’s another reason for making food variety part of your eating style!

Enjoy your favorite foods and your favorite places to eat. After all, no foods or meals are “good” or “bad.” The foods you choose for the whole day, even several days, are what counts.

Eat at least the lowest number of servings recommended for each food group daily. And enjoy just a bit from the Pyramid tip.

For more information on how you can fit the Food Guide Pyramid into your daily eating plan.

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