Girls Growth Chart Calculator
Find where a girl’s growth falls on the CDC growth charts. Enter her age (2 to 20 years), height and weight, and the tool computes her BMI plus her height-for-age, weight-for-age and BMI-for-age percentiles with z-scores, using the actual CDC LMS reference tables, the same data behind the charts pediatricians plot. This is a screening aid, not a diagnosis: discuss any result with her pediatrician.
For girls aged 2 to 20 using the CDC 2000 growth reference. Under 2 years, pediatricians use the WHO growth standards instead. Percentiles are screening tools, not diagnoses.
Quick Answer
For the pre-filled example, a girl aged 10 years 0 months, 140 cm tall and 35 kg: BMI is 17.86, height-for-age is the 60.43th percentile (z = 0.26), weight-for-age is the 61.16th percentile (z = 0.28), and BMI-for-age is the 65.29th percentile (z = 0.39), inside the CDC healthy weight range of the 5th to below the 85th percentile. Change any input and press Calculate percentiles to get her numbers.
How to Use This Calculator
Three measurements and her exact age are all the tool needs. Measure height standing, without shoes, heels and back against a wall, and weigh her in light clothing on a level floor.
Enter her age in years plus any extra months, then her height and weight in metric or imperial units. Press Calculate percentiles. The result shows her BMI, all three percentiles with z-scores, a plain-language note for each one, and the BMI weight-status band. Copy or share the result straight from the results box if you want to take it to an appointment. One honest limit: the tool gives a snapshot for one date. Growth is a trend, so the same numbers mean more when you repeat them every few months and watch the line she follows.
How the Percentiles Are Computed: The CDC LMS Method
A percentile is not a percentage score. It is her rank against the CDC reference population of girls the same age.
The CDC publishes three parameters for each measure at each half-month of age: L (the Box-Cox power that corrects skew), M (the median) and S (the generalized coefficient of variation). For a measurement X, the z-score is z = ((X / M)^L – 1) / (L x S), with a log form used if L were 0. The percentile is the standard normal cumulative probability of that z-score. This tool embeds the published girls tables for stature, weight and BMI, interpolates L, M and S linearly between the half-month rows for her exact age, and adds 0.5 months to her completed age, the CDC half-month convention the data files themselves specify. Her BMI is computed first, as weight in kilograms divided by height in meters squared, and then looked up in the BMI table the same way. Every LMS row in this tool was checked against the CDC percentile data files during the rebuild of this page: all 655 rows match the official girls values.
Worked Example, Checked Against This Exact Tool
The worked example is the pre-filled one, so you can reproduce it in seconds. A girl aged 10 years 0 months, height 140 cm, weight 35 kg.
BMI = 35 / 1.40^2 = 17.86. At an age of 120.5 months (10 years plus the half-month convention), the tool interpolates the girls tables and returns: height-for-age 60.43th percentile (z = 0.26), weight-for-age 61.16th percentile (z = 0.28), BMI-for-age 65.29th percentile (z = 0.39). All three sit near the middle of the chart, and the BMI percentile falls in the healthy weight band. If your run shows different numbers, check the unit switches next to height and weight first: entering 140 as inches or 35 as pounds changes the result completely, and the tool validates only for implausible ranges, not for a wrong unit choice.
What Each Percentile Means
Each of the three percentiles answers a different question, and they are not interchangeable. Height-for-age shows how her stature compares with girls her age and is the slowest-moving of the three. Weight-for-age mixes height and build together, which is why the CDC treats it as a tracking aid rather than a weight-status measure. BMI-for-age adjusts weight for height and age, and it is the CDC’s preferred screening measure for weight status from age 2.
| BMI-for-age percentile | CDC category | What it usually means |
|---|---|---|
| Below the 5th | Underweight | Worth discussing at the next visit, sooner if she is also falling on height. |
| 5th to below 85th | Healthy weight | The expected range for most girls. Trend still matters more than one point. |
| 85th to below 95th | Overweight | A prompt to review activity, sleep and family habits with her pediatrician. |
| 95th and above | Obesity | A screening flag for a fuller assessment, not a verdict on health by itself. |
Two cautions belong with any single reading. First, puberty timing moves percentiles: an early developer can ride high on height and BMI for a few years and settle back. Second, percentiles compress at the extremes, so above the 97th percentile the z-score is the more informative number, which is why this tool always shows both. For a different kind of percentile at the same visits, the blood pressure percentile calculator places a child’s reading against its own age, sex and height reference.
Why Under-2s Are Excluded
The CDC and the American Academy of Pediatrics recommend the WHO growth standards, not the CDC charts, from birth to 2 years. The two references were built from different populations: the WHO standards describe how breastfed infants in six countries actually grew under good conditions, while the CDC charts describe how US children did grow in surveys from 1963 to 1994.
A CDC percentile for a baby would compare her with the wrong reference entirely, so this tool shows an explanation and declines, rather than print a misleading number. If she is under 2, her pediatrician is already plotting her on the WHO charts at her checkups.
What Competing Calculators Miss
The official CDC calculator computes BMI-for-age only, so it cannot tell you her height or weight percentile. Baylor’s well-known children’s calculator adds energy requirements but still leads with BMI. Several third-party girls chart pages publish rounded milestone tables labelled as approximations, or bury the method entirely, and at least one popular page used invented linear formulas instead of reference data. This tool’s differences are concrete: all three percentiles plus z-scores in one run, the real published LMS tables rather than an approximation, an explicit refusal under age 2 instead of a fabricated baby percentile, and a stated half-month age convention you can audit. The mirror image for boys is the boys growth chart calculator, which uses the separate boys tables. Families who use pediatric tools at home may also meet the amoxicillin pediatric dosing calculator at the same visits; dosing, like growth, should always be confirmed with the clinician who knows her.
Frequently Asked Questions
From the CDC LMS tables: z = ((measurement / median)^L – 1) / (L x S) at the child’s exact age in months, then the percentile is the normal-distribution probability of that z-score. This tool interpolates L, M and S between the published monthly rows, which is the method the CDC itself describes for ages between table rows.
There is no good value: the 50th percentile is average by definition, and a healthy girl can track anywhere along the chart. Pediatricians watch for values below the 5th or above the 95th percentile, and especially for a child crossing percentile lines over time.
The CDC weight-status categories for ages 2 to 20 are: below the 5th percentile is underweight, 5th to below the 85th percentile is healthy weight, 85th to below the 95th percentile is overweight, and the 95th percentile and above is obesity. These are screening categories, not diagnoses.
The CDC growth charts cover ages 2 to 20. From birth to age 2, the CDC and the American Academy of Pediatrics recommend the WHO growth standards, which were built from breastfed infants in six countries, so this tool declines rather than compute a percentile against the wrong reference.
A z-score is the number of standard deviations a measurement sits from the median for that age and sex. A z-score of 0 is the 50th percentile, +1.64 is about the 95th percentile, and -1.64 is about the 5th. Clinicians prefer z-scores for tracking change because they stay meaningful at the extremes, where percentiles bunch up.
A single shift like that can be normal variation, measurement error, or an early or late growth spurt. The classic reason pediatricians investigate is a drop crossing two or more major percentile lines, or a percentile paired with symptoms. Bring the trend over time to the visit, not one point.
No. Growth patterns differ by sex, so the CDC publishes separate reference tables for girls and boys. This tool uses only the girls tables; the separate boys growth chart calculator uses the boys tables.
Pediatricians plot premature babies by corrected age, their age from the due date rather than the birth date, until about age 2. After that most children are plotted by chronological age. Enter the corrected age here for a child under 2, and confirm the approach with her pediatrician.
The CDC publishes LMS values at half-month points and describes interpolation as the way to get values at finer age intervals. The error from interpolation is far smaller than ordinary measurement error from posture, time of day, or a wiggly child.
No. A percentile is a screening result that says how a measurement compares with the reference population. Diagnosing a growth disorder takes a clinician, a growth history over time, and often lab work or a bone-age X-ray.
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References
- Centers for Disease Control and Prevention. Growth Charts: Percentile Data Files with LMS Values. The official LMS tables and the interpolation method this tool uses. Accessed October 21, 2026.
- Centers for Disease Control and Prevention. Growth Charts: Clinical Growth Charts. The printed girls stature, weight and BMI charts for ages 2 to 20. Accessed October 21, 2026.
- Centers for Disease Control and Prevention. Child and Teen BMI Calculator. The official BMI-only calculator and the CDC weight-status categories. Accessed October 21, 2026.
- Centers for Disease Control and Prevention. Healthy Weight and Growth. CDC guidance on child growth, BMI screening and when to talk to a clinician. Accessed October 21, 2026.
- Centers for Disease Control and Prevention. 2000 CDC Growth Charts: Features and Data. How the reference population and smoothed curves were built. Accessed October 21, 2026.
- Centers for Disease Control and Prevention. Growth Charts: WHO Growth Standards Data Files. The birth-to-2-years reference the CDC recommends instead of the CDC charts. Accessed October 21, 2026.
- World Health Organization. Child Growth Standards. The WHO standards for children under 5 and how they were collected in six countries. Accessed October 21, 2026.
- Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC Growth Charts for the United States: Methods and Development. Vital and Health Statistics, Series 11, No. 246, 2002. The primary methods paper behind the charts. Accessed October 21, 2026.
- American Academy of Pediatrics, HealthyChildren.org. Growth Charts: By the Numbers. A parent-facing explanation of percentiles from the AAP. Accessed October 21, 2026.
- Centers for Disease Control and Prevention. CDC Extended BMI-for-Age Growth Charts. Background on BMI percentiles above the 95th percentile and why standard percentiles compress at the extremes. Accessed October 21, 2026.
- National Center for Health Statistics. CDC Growth Charts: United States. Advance Data No. 314, 2000. The original release of the revised charts. Accessed October 21, 2026.
Disclaimer: This calculator is a screening aid for education only. It does not diagnose any condition. Discuss any growth concern, and any single result that worries you, with her pediatrician, who can plot her growth over time.