BMI for girls at 20 years

At 20 years, the median BMI for girls on the CDC 2000 growth charts is 21.7 kg/m²: half of girls this age have a lower BMI and half a higher one. The middle half of girls, from the 25th to the 75th percentile, falls between 19.8 and 24.4 kg/m², a spread of 4.6 kg/m². The outer lines of CDC’s BMI-for-age chart, the 5th and 95th percentiles, sit at 17.8 and 31.8 kg/m².

Since 19 years, the median has risen by 0.2 kg/m² over 1 year.

For boys at 20 years the median is 23.0 kg/m², 1.3 kg/m² more than for girls, which is why the charts are drawn separately by sex.

CDC uses BMI-for-age, not weight-for-length, from age 2. At 20 years the 85th percentile for girls is 26.5 and the 95th is 31.8 kg/m². Above the 95th percentile, CDC's 2022 extended charts replace the original curve, so the 99th percentile here is 41.8 kg/m², computed with the extended method.

Reading the table: a girl at 20 years with a BMI of 23.5 kg/m² is at about the 68th percentile, meaning that out of 100 girls this age, about 68 have a lower BMI.