Child height percentile and growth chart

Enter your child's height at one or more ages to see where it falls against the WHO growth standards, the US CDC growth charts or China's national standards, with the measurements plotted on the chart. Add the parents' heights and, if a doctor has measured it, the bone age, to see what adult height the numbers point to — and how uncertain that is.

How to use it

Choose boy or girl, and the growth reference. WHO is designed for international use; the CDC charts are used in the United States for children from 2; the Chinese standards describe Chinese children.
Enter at least one measurement: age in years and months, and height in centimetres. Children under two are measured lying down (length); from two, standing (height). Add earlier measurements from health records to see the growth track.
Optionally enter both parents' heights, and a bone age if your child has had a hand X-ray read by a doctor.
Read the percentile, the projections and the chart. The chart shows the median and the ±1 and ±2 standard deviation lines for the chosen reference, your measurements in red and, if you entered the parents' heights, their target range on the right.

Where the curves and the estimates come from

Three sets of growth references

The WHO Child Growth Standards describe how healthy, breastfed children grow from birth to 5 years in good conditions; the WHO growth reference for 5 to 19 years continues them to adulthood. The US CDC growth charts cover ages 2 to 20. Both publish L, M and S parameters for every month of age, from which the tool calculates the exact z-score for any height with the LMS method: z = ((height ÷ M)^L − 1) ÷ (L × S). China's health commission publishes WS/T 423-2022 for children under 7 and WS/T 612-2018 for ages 7 to 18, as tables of height at −2, −1, 0, +1 and +2 standard deviations; the tool interpolates between the table points. All three data sets were taken directly from the official files.

The percentile is the share of children of the same age and sex who are shorter. A z-score of 0 is the median (50th percentile); −2 is about the 2nd percentile and +2 about the 98th. China's WS/T 612-2018 grades height as below −2 SD, −2 to −1 SD, within ±1 SD, +1 to +2 SD and above +2 SD, and the tool uses the same bands for every reference.

Parents' target height

Children's adult height is strongly related to their parents'. The American Academy of Pediatrics gives the mid-parental height as the average of the parents' heights, plus 5 inches (12.7 cm) for a boy or minus 5 inches for a girl, and says about 95% of children reach an adult height within 4 inches (10.2 cm) of it. The approach goes back to Tanner, Goldstein and Whitehouse (1970), who showed that allowing for parents' height makes growth charts considerably more precise.

Projection and bone age

The adult-height projection assumes the child keeps the same z-score to the end of the reference: 18 for the Chinese standards, 19 for WHO and 20 for CDC. Bone age, read from a hand X-ray, measures how mature the skeleton is. A child whose bone age is ahead of their real age has used up more of their growth, so the tool, when you give a bone age, also calculates the z-score for the bone age instead of the real age. This is a rough adjustment. Clinical methods such as Bayley-Pinneau, Tanner-Whitehouse (TW3) or China's CHN method use specific tables and must be applied by a doctor to the X-ray.

Examples

Boy, 8 years, 129 cm	z-score	Percentile	Adult if percentile holds	With bone age 9
China standards	−0.28	39th	169.7 cm at 18	164.9 cm
WHO	0.31	62nd	178.8 cm at 19	172.2 cm
US CDC	0.19	58th	178.2 cm at 20	171.6 cm

The same child is below average on the Chinese standards and above average on WHO and CDC. The reason is visible in the medians: Chinese boys of 8 are taller on average (130.7 cm) than the WHO reference (127.3 cm), but their adult median is lower — 171.4 cm at 18 against 176.5 cm at 19 for WHO. Which reference you use changes both the percentile and the projection, so compare like with like.

With a father of 175 cm and a mother of 160 cm, a boy's target height is (175 + 160 + 12.7) ÷ 2 = 173.9 cm, with a range of 163.7 to 184.0 cm; a girl's is 161.2 cm, range 151.0 to 171.3 cm.

Limits

Projections are uncertain, especially before puberty. Children often move between percentiles, and the timing of puberty shifts height a great deal. Treat the adult figure as a rough indication, not a forecast.
Bone age must come from a doctor. The tool only uses a bone age you enter; it cannot estimate one. The adjustment it makes is simpler than clinical prediction methods.
Two Chinese standards meet at age 7. WS/T 423-2022 ends at 6 years 9 months and WS/T 612-2018 starts at 7 years; the lines show a small step there because they come from different surveys.
Premature babies should be plotted at corrected age in the first years; enter the corrected age.
Not a diagnosis. Height well below the lines, growth that crosses percentile lines, or early or late puberty should be assessed by a paediatrician.

Frequently asked questions

What percentile is normal for height?

Most healthy children are between the 3rd and 97th percentiles. What matters most is that a child keeps growing along roughly the same line over time.

How do I predict my child's adult height?

Two simple methods: keep the current percentile to adulthood, or use the parents' target height. The tool shows both; a doctor can add a bone-age-based prediction.

Should I use the WHO or the Chinese growth chart?

Use the reference your child's doctor uses. Chinese children are compared with the Chinese national standards in China; WHO is the international reference.

What is bone age?

A measure of skeletal maturity read from an X-ray of the left hand and wrist. If it is ahead of real age, less growth remains; if behind, more.

Is my child's data stored?

No. Everything is calculated in your browser and nothing is saved.