Growth percentiles (CDC 2 to 20 years)

Weight, stature, and BMI-for-age percentiles and z-scores, with BMI category and severe obesity class by percent of the 95th percentile.

Version 0.1.0

Inputs

SexUsed by the equation
Age from
2 to 20 years
Optional if height is entered
Standing height. Optional if weight is entered

Sex, weight, and height are shared with every calculator.

When to use
  • Children and adolescents 2 to 20 years old at well visits, nutrition assessment, and obesity follow-up.
  • Stature should be standing height; use the WHO infant calculator under 2 years.
Pearls and pitfalls
  • Weight status: BMI below the 5th percentile underweight, 5th to below 85th healthy weight, 85th to below 95th overweight, 95th or above obesity.
  • Severe obesity: class 2 at 120% of the 95th percentile or more, class 3 at 140% or more. Percent of P95 tracks change better than z-scores at very high BMI.
  • Above the 95th percentile this uses the CDC 2022 extended BMI-for-age method; the 2000 LMS z-score compresses at high BMI and is shown for comparison.
  • Values far from the median (modified z beyond CDC limits) are flagged as possibly implausible; recheck the measurement first.
Formula

z = ((X/M)^L − 1) ÷ (L × S) (or ln(X/M) ÷ S when L = 0); percentile = Φ(z); L, M, S interpolated by age. BMI above the 95th percentile (CDC 2022 extended): percentile = 90 + 10 × Φ((BMI − P95) ÷ sigma), z = Φ⁻¹(percentile ÷ 100); % of P95 = BMI ÷ P95 × 100

Evidence

  1. Primary Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC Growth Charts for the United States: methods and development. Vital Health Stat 11. 2002;(246):1-190. PubMed 12043359
  2. Primary Hales CM, Freedman DS, Akinbami L, Wei R, Ogden CL. Evaluation of alternative body mass index (BMI) metrics to monitor weight status in children and adolescents with extremely high BMI using CDC BMI-for-age growth charts. Vital Health Stat 1. 2022;(197):1-42. PubMed 36598420
  3. Supporting 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. PubMed 32901504
  4. Guideline Grummer-Strawn LM, Reinold C, Krebs NF. Use of World Health Organization and CDC growth charts for children aged 0-59 months in the United States. MMWR Recomm Rep. 2010;59(RR-9):1-15. PubMed 20829749

Reference data: CDC growth chart data files and CDC-hosted WHO Child Growth Standards tables (public domain). API: POST /api/v1/calculate/growth-cdc with sex, ageMo (months), and measurements.

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