Child Growth Percentile (WHO 0–2 + CDC 2–20)
Look up weight-for-age and length/height-for-age percentiles for children 0 to 20 years using WHO standards (0–2 y) and CDC reference growth charts (2–20 y).
LMS parameters interpolated from WHO Child Growth Standards (0–2 years, MGRS 2006) + CDC 2000 Reference Growth Charts (2–20 years), per CDC 2010 recommendation. Z-score: z = ((Y/M)^L − 1) / (L·S). Percentile from standard normal CDF. Sparse age points are interpolated linearly — use a clinical chart for between-visit precision. The 3rd–97th percentile band is conventional normal range; below or above warrants pediatric follow-up.
General calculation reads
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About this tool
Pediatric growth percentiles compare a child to a reference population. Per the CDC 2010 recommendation (still current), US clinicians use the WHO Child Growth Standards for ages 0–24 months and CDC 2000 Growth Reference Charts for ages 2–20 years. The WHO standards are based on the Multicenter Growth Reference Study (Brazil, Ghana, India, Norway, Oman, USA — exclusively breastfed infants under optimal conditions) and represent how children should grow. The CDC charts are based on US population data and represent how children did grow in NHANES surveys. Both charts use the LMS method (Lambda-Mu-Sigma) where each age/sex point has three parameters: L (skewness), M (median), S (CV). The z-score formula is: z = ((measurement/M)^L − 1) / (L × S) when L ≠ 0, or z = ln(measurement/M) / S when L = 0. The percentile is the standard normal CDF of the z-score × 100. Clinically, a percentile between the 3rd and 97th is considered normal range; below 3rd or above 97th warrants follow-up. Trends across visits matter more than any single percentile.
How to use it
- Enter the child age (years), sex, weight (kg), and height/length (cm).
- See weight-for-age and height/length-for-age percentiles.
- A percentile is the % of same-age, same-sex peers below this measurement.
- Below 3rd or above 97th — discuss trend with your pediatrician.
Frequently asked questions
- What is a "good" percentile?
- Any consistent percentile between the 3rd and 97th is normal. A 10th-percentile child who tracks at the 10th over time is healthy. A child dropping from the 50th to the 10th over 6 months warrants evaluation.
- Why WHO under 2 and CDC over 2?
- CDC recommendation 2010: WHO standards reflect optimal breastfed growth under 2 and are a prescriptive standard. CDC charts over 2 reflect actual US growth patterns and are descriptive. The two transition smoothly at 24 months.
- Are these still current?
- The CDC published an extended BMI-for-age chart in 2022 for severe obesity (above 97th percentile) but the base 2000 charts remain in use. WHO standards are unchanged since 2006.
- Does this work for premature babies?
- No — use a separate preterm growth chart (Fenton 2013) until the child reaches corrected age 50 weeks, then transition to WHO standards by corrected age.
- Is data sent anywhere?
- No. All math runs in your browser.