CDC Height for Age Percentiles for Boys (2 - 20 years)

Z Score  
Decimal Precision:
Height for Age Percentile Interpretation
Percentile < 5:Short stature
Percentile >= 5 and < 95:Normal stature
Percentile >= 95:Tall stature
In some cases, including consideration of pharmacotherapy, more stringent definitions of short or tall stature are used, with thresholds of < 3rd percentile or < 1st percentile for short stature, and > 97th or > 99th percentile for tall stature.
At the extremes (> 97th percentile or < 3rd percentile), small differences in percentiles represent clinically important differences in height. At these extremes, the z-score is a more precise reflection of how far the measurement deviates from the mean, and is a useful tool for tracking changes.
Z-scorePercentile equivalent
- 3.00.3
- 2.02.5
+ 2.097.5
+ 3.099.7

  1. Percentile conversion from Z-Score is done by table look-up in the standard Normal Table. Percentiles are provided for Z Scores between -3.09 and 3.09. Values beyond these extremes return percentiles of 0.1 and 99.9 respectively.
  2. LMS Parameters for Boys: Height for Age. National health and nutrition survey (NHANES), CDC/National Center for Health Statistics.
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