At the extremes of the charts, predicted percentiles (and Z-scores) much over the 95th percentile using the CDC charts may be inaccurate.

The PediTools CDC 2 - 20y calculator has been updated to classify obesity using the BMI relative to the 95th percentile BMI for more severe obesity. In brief, categories of obesity for children or adolescents >2 years of age (per Styne 2017):

• Overweight, for BMI >= 85th but <95th percentile
• Obese, for BMI >= 95th percentile
• Extremely obese if the BMI is >=120% of the 95th percentile or >=35 kg/m2

Thanks to the dietician who provided this feedback!