Child's Measurements
Percentiles
Growth chart
Sources and method
Does race or ethnicity change the result?
No. Neither CDC nor WHO publishes race-specific growth charts, so this page doesn't ask for race. CDC states that race is not a factor in calculating BMI percentiles.
The CDC 2000 charts were built from five national surveys (NHES II and III, NHANES I, II and III, 1963 to 1994), with sample weights so the reference matches the age, sex and racial and ethnic makeup of US children.
WHO measured breastfed children raised in healthy conditions in Brazil, Ghana, India, Norway, Oman and the United States. Only 3% of the variation in length came from differences between sites, against 70% between individual children, which is why WHO pooled them into one international standard.
Some countries publish national charts for their own children. Those aren't included here.
Which reference to use
United States (CDC)
Follows the CDC and AAP recommendation: WHO growth standards from birth to 2 years, then the CDC 2000 growth charts from 2 to 20 years. Above the 95th percentile, BMI uses CDC's 2022 extended BMI-for-age method, which keeps percentiles and z-scores meaningful at very high BMI.
International (WHO)
WHO 2006 Child Growth Standards from birth to 5 years, then the WHO 2007 Growth Reference from 5 to 19 years. WHO publishes weight-for-age only up to 10 years, because it can't separate height from body mass during puberty; use BMI-for-age after that.
Weight-for-length
Both options use the WHO weight-for-length standard under 2 years (lengths 45 to 110 cm), the measure CDC and AAP recommend at that age. The international option adds WHO weight-for-height from 2 to 5 years (heights 65 to 120 cm). From 2 years in the US, and from 5 years for WHO, BMI-for-age takes its place.
Caveats
- A child's percentile can shift when the reference changes at 2 years (US) or 5 years (WHO). Compare like with like when tracking a child over time.
- CDC and AAP don't use BMI-for-age under 2 years; weight-for-length is the recommended measure. BMI under 2 is still shown, against the WHO standard.
- Weight-for-length compares weight with other children of the same length, whatever their age, so it doesn't flag a child who is short and light for age. Read it with length-for-age.
- The CDC 2000 charts leave out NHANES III weights for children 6 and older, so the reference predates most of the rise in childhood obesity.
- Percentiles describe where a measurement sits in a reference population. Interpret them with growth over time, parents' heights and the clinical picture.
Categories
CDC BMI-for-age, 2 to 20 years
| Category | Percentile |
|---|---|
| Underweight | Below the 5th |
| Healthy weight | 5th to below 85th |
| Overweight | 85th to below 95th |
| Obesity | 95th or higher |
| Severe obesity, class 2 | 120% of the 95th, or BMI 35 |
| Severe obesity, class 3 | 140% of the 95th, or BMI 40 |
Under 2 years in the US
CDC and AAP use the WHO charts with the 2.3rd and 97.7th percentiles (±2 SD) as cutoffs. Weight-for-length above the 97.7th is high and below the 2.3rd is low.
CDC doesn't name categories for weight- or height-for-age. This page flags values beyond ±2 SD (below the 2.3rd or above the 97.7th percentile).
WHO cutoffs
- Under 5, weight-for-length/height and BMI-for-age: above +1 SD possible risk of overweight, above +2 SD overweight, above +3 SD obesity; below −2 SD wasted, below −3 SD severely wasted.
- 5 to 19, BMI-for-age: above +1 SD overweight, above +2 SD obesity; below −2 SD thinness, below −3 SD severe thinness.
- Length/height-for-age: below −2 SD stunted, below −3 SD severely stunted.
- Weight-for-age: below −2 SD underweight, below −3 SD severely underweight.
How the numbers are worked out
L, M and S are the published values for the child's sex and age, interpolated linearly between table ages. For weight-for-length they are looked up by length instead, interpolated between rows 0.5 cm apart. WHO weight-based measures beyond ±3 SD use WHO's restricted LMS method.
With a birth date, age is the exact number of days divided by 30.4375, as in CDC's SAS program and WHO Anthro. With years and months, CDC's half-month convention adds 0.5 to the completed months.
Results were checked against 333 published values: CDC percentile tables, CDC extended-BMI z-scores and worked examples, and z-scores in WHO's own AnthroPlus survey data. All agree to the published rounding. Weight-for-length and weight-for-height were checked against 120 values computed from WHO's full 0.1 cm tables the way WHO Anthro does, and agree within 0.002 SD.
Sources
- Kuczmarski RJ, et al. 2000 CDC growth charts for the United States: methods and development. Vital Health Stat 11 2002;(246). CDC growth chart data files (LMS).
- CDC. Extended BMI-for-age growth charts, 2022. Data file and formulas.
- 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. CDC summary.
- CDC. Child and teen BMI categories.
- WHO Multicentre Growth Reference Study Group. WHO Child Growth Standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age, 2006. LMS tables from the WHO anthro package.
- de Onis M, et al. Development of a WHO growth reference for school-aged children and adolescents. Bull World Health Organ 2007;85:660–667. LMS tables from the WHO anthroplus package.
- WHO Multicentre Growth Reference Study Group. Assessment of differences in linear growth among populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl 2006;450:56–65. doi:10.1111/j.1651-2227.2006.tb02376.x.
For screening and education, not a diagnosis. A percentile says where one measurement falls in a reference population; growth over time matters more than any single value.