On this page is a BMI percentile by age calculator for ages 2 years old and older in the United States. Enter an age range and a BMI to rank it in the BMI distribution by age. Select multiple age ranges to see how BMI distribution changes for citizens of different ages in the United States.
BMI, or Body Mass Index, is based on height and weight and estimates whether a person is in a healthy body composition range. Use our BMI Calculator to compute Body Mass Index.
BMI Percentile by Age Calculator for the United States
Data comes from 5,662 adults with valid BMIs in the CDC's 2015-16 NHANES survey. Heights and weights measured at a mobile examination center. Age ranges include between 313 (70-74) and 671 (18-24) samples.
Median and Average BMI by Age in the United States
In 2016, the United States adult BMI average was 29.3. The United States adult BMI median was 28.2.
BMI Statistics for Children in the United States, by Age Range
Note that BMI for children shouldn't be compared directly to adult BMIs.
While relative BMI is important, the CDC evaluates BMIs for children (and even young adults) with growth potential differently.
Here are summary BMI statistics for children under age 18 in the United States:
| Age Range | 25th Percentile BMI | Median BMI | 75th Percentile BMI | Average BMI |
| 2-3 | 15.6 | 16.3 | 17.2 | 16.5 |
| 4-5 | 15.3 | 16.1 | 17.3 | 16.5 |
| 6-7 | 15.0 | 16.1 | 18.4 | 17.2 |
| 8-9 | 15.8 | 17.3 | 19.8 | 18.3 |
| 10-11 | 16.8 | 19.2 | 22.4 | 20.2 |
| 12-13 | 18.2 | 20.6 | 25.1 | 22.0 |
| 14-15 | 19.4 | 22.0 | 25.6 | 23.4 |
| 16-17 | 21.2 | 24.1 | 27.8 | 25.3 |
BMI Distribution by Age for Adults in the United States
Here are the BMI statistics for adult age ranges in the United States:
| Age Range | 25th Percentile BMI | Median BMI | 75th Percentile BMI | Average BMI |
| 18-24 | 21.9 | 25.5 | 30.7 | 27.1 |
| 25-29 | 22.5 | 26.4 | 31.7 | 27.9 |
| 30-34 | 24.4 | 28.1 | 33.5 | 29.6 |
| 35-39 | 24.7 | 29.0 | 34.3 | 30.2 |
| 40-44 | 24.6 | 29.1 | 33.4 | 30.1 |
| 45-49 | 25.2 | 28.6 | 33.1 | 29.7 |
| 50-54 | 24.9 | 29.1 | 33.6 | 30.1 |
| 55-59 | 25.0 | 29.2 | 33.1 | 29.8 |
| 60-64 | 24.3 | 28.9 | 34.2 | 30.5 |
| 65-69 | 25.7 | 29.0 | 33.8 | 30.0 |
| 70-74 | 25.6 | 28.6 | 33.0 | 29.8 |
| 75+ | 24.1 | 27.5 | 31.2 | 28.1 |
American BMI Distribution by Age
Disclaimer: nothing on this site is medical advice! BMI is best used contextually, and BMI readings for still-growing youth mean something different than for adults at terminal height. Consult a professional if you have any concerns about BMI.
As I've noted in this post, you can't directly compare BMI between children and adults who are still growing versus adults who have stopped. However, comparing adult BMIs is an interesting exercise.
In the United States, average BMI goes from around 27 in the 18-24 age range up to 30 for all ages 35-74.
It's only for ages 75 and up that we see a reduction in average BMIs again. Some of this is survival bias - all cause mortality increases significantly at higher BMIs, which will show in the older populations. Further, some of the reduction is a loss of lean mass in older age. Muscle mass decreases with age which can inappropriately skew results lower.
As we mentioned in our BMI distribution for all Americans and BMI Distribution for men and women posts, BMI isn't the best indicator of physical health for an individual. Other measures, such as body fat percentage, are better for measuring body composition.
