π Child Height Percentile Calculator
CDC stature-for-age percentile for ages 2 to 20.
Growth screening only. Discuss growth concerns with your pediatrician.
Is your child short, tall, or right on track? The answer is a percentile: the CDC's stature-for-age chart compares your child's height to same-age, same-sex peers using the LMS method, the same statistical engine behind BMI percentiles. Enter age, sex, and height for the exact percentile, the median height for comparison, and guidance on when the number warrants a pediatrician's look.
How to Use This Calculator
Measure height carefully, enter age and sex, and read the percentile.
Measure without shoes, back and heels against a wall, looking straight ahead. Morning is tallest; evening can read half an inch shorter.
Enter exact age (8.5 for eight and a half) and sex. The CDC tables shift monthly.
Read the percentile. Between the 3rd and 97th is the typical range; outside it, or a big shift across percentiles, deserves a pediatrician visit.
Pair with weight percentile and BMI percentile for the full growth picture.
The CDC Stature-for-Age Method
Height percentiles use the same LMS machinery as BMI percentiles: for each month of age from 2 to 20, each sex, the CDC publishes the L (skew), M (median), and S (spread) parameters fitted from national survey data. This page embeds the actual published values at each year and interpolates between them. The z-score converts any height into standard deviations from the median, and the normal curve turns that into a percentile.
Unlike BMI, height has no "healthy band" with hard cutoffs: the 3rd to 97th percentile range is the convention for typical, and being at the 2nd or 99th is a flag for evaluation, not a diagnosis. Genetics dominate: mid-parental height predicts a child's percentile corridor, and pediatricians get more signal from whether a child follows their own curve than from which curve they are on.
Worked Example
An 8-year-old girl, 127 cm (50 inches). CDC parameters for 8-year-old girls: L = -0.09, M = 127.35, S = 0.0459. z = ((127/127.35)^-0.09 - 1) / (-0.09 x 0.0459) = 0.06, percentile 47.6: almost exactly median. Now a boy the same age at 120 cm: parameters L = 0.47, M = 127.63, S = 0.0451, z = -1.34, percentile about 9: short-ish but inside the typical range, worth watching only if he is falling off his own curve. The same 120 cm at age 6 would be near the 50th: age changes everything.
What Matters More Than the Number
Growth velocity beats any single percentile. A child who has tracked the 25th percentile for years is following their curve; a child who drops from the 50th to the 15th in a year is telling you something, even though the 15th is "normal." Pediatricians plot serial measurements for exactly this reason, and they compare against mid-parental height: a child of two short parents at the 10th percentile is usually just genetics, while the same percentile in a child of tall parents raises eyebrows.
Puberty timing scrambles the chart temporarily: early developers shoot up the percentiles, then peers catch up; late developers linger low, then surge. Bone age X-rays resolve the question when it matters. True growth concerns, crossing percentiles downward persistently, or height below the 3rd with no family explanation, prompt evaluation of thyroid, growth hormone, chronic disease, and nutrition. Most short kids are healthy; the workup exists to find the few who are not.
Measuring Right
Home measurements routinely err by half an inch or more: slouching, thick hair, measuring in the evening, or a soft tape instead of a wall. Use a hard floor, a wall, a book pressed flat on the head, and a pencil mark. Measure twice and average. Record the date, because velocity needs time between points: remeasure no more often than every 6 months, since monthly checks just manufacture noise and worry. Bring your home log to well-child visits; pediatricians would rather see your data than hear your worry.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
What is a normal height percentile for a child?
Between the 3rd and 97th percentile is the typical range on CDC charts. The 50th is the median. What matters most is following a consistent percentile curve over time, not which percentile it is.
How is height percentile calculated?
With the CDC LMS method: z = ((height/M)^L - 1)/(L x S), using the L, M, S parameters for the child's sex and exact age in months, then converting the z-score to a percentile. This calculator uses the actual published CDC parameters.
My child is in the 5th percentile for height. Should I worry?
Not necessarily. A child consistently tracking the 5th percentile, especially with shorter parents, is usually just small and healthy. Worry more about falling across percentile lines over time, or height below the 3rd percentile without family explanation. Discuss with the pediatrician.
Can you predict adult height from a child's percentile?
Roughly. Children tend to stay near their percentile corridor: mid-parental height formulas ((father + mother)/2 +/- 5 inches, +/- for boys/girls) predict adult height within about 4 inches for most kids. Bone age X-rays refine it when needed.
Why does my child measure shorter in the evening?
Spinal discs compress during the day under gravity; everyone is tallest in the morning and up to half an inch shorter by evening. Measure in the morning for consistency, and always compare morning to morning.
Do boys and girls use different height charts?
Yes. The CDC publishes separate stature-for-age LMS tables by sex, reflecting different growth timing and final heights. This calculator selects the right table automatically.
What causes a child to drop height percentiles?
Possibilities include hypothyroidism, growth hormone deficiency, chronic disease (celiac, kidney, heart), poor nutrition, and late puberty (which usually resolves). Persistent downward crossing of percentiles warrants pediatric evaluation.
How often should I measure my child's height?
Every 6-12 months at home; more often just adds noise. Pediatricians measure at well-child visits. Growth velocity needs time between measurements to be meaningful.
At what age do height percentiles stop being used?
The CDC charts run to age 20. After growth plates close (usually 14-18 depending on sex and puberty timing), adult height is set and percentiles no longer apply.
Does nutrition affect height percentile?
Severe malnutrition stunts growth, but in well-fed populations genetics dominate. No food, supplement, or exercise meaningfully increases final height beyond genetic potential. Adequate sleep, nutrition, and treating illness let a child reach their potential.