This version was machine-translated from German and has not been medically reviewed. The authoritative version is the German version.

CDC Extended BMI

BMI-for-age 2–20 years incl. values above P95 and % of P95

About this calculator

BMI percentile and z-score according to the extended CDC BMI curves (2022), which also give meaningful values above the P95. In addition, BMI as a percentage of the P95 for classifying obesity classes.

The z-score (SDS) describes the deviation from the median in standard deviations; the percentile is the proportion of the reference population with a smaller value.

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Reference and license

CDC Extended BMI – 2–20 years.
Wei R, Ogden CL, Parsons VL, Freedman DS, Hales CM. A method for calculating BMI z-scores and percentiles above the 95th percentile of the CDC growth charts. Ann Hum Biol. 2020;47(6):514–521. Hales CM et al. Use of extended BMI-for-age growth charts. Pediatrics 2022. License: Public domain (US federal agency). Source
Below P95 identical to CDC 2000; above it, half-normal distribution according to Wei 2020. In addition, the BMI is given as a percentage of P95.

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Note

Calculation aid for healthcare professionals. Percentiles and z-scores describe the position of a measured value in the reference population; clinical assessment remains with the treating physician.

Review date of the German original: 2026-11-05 · Methodology

For parents (in German): Percentile calculator (kinderarzt.net)

Frequently asked questions

Why is the classic CDC BMI curve not sufficient?

Above P97, the LMS curves of 2000 no longer yield meaningful z-scores. The extended curves (Wei et al. 2020, Hales et al. 2022) model the range above P95 with a half-normal distribution.

What does percent of P95 mean?

The BMI is expressed relative to P95 for age and sex: from 100 % obesity is present (class 1). Class 2 starts at 120 % of P95 or a BMI of 35 kg/m², class 3 at 140 % or a BMI of 40 kg/m² – the lower of the two thresholds is decisive in each case (CDC, American Academy of Pediatrics).