Children grow at different rates, and the growth chart is how clinicians tell whether a child’s height is typical for their age. The chart does not give a “right” height; it shows the spread among children of the same age and sex. This calculator turns a measurement into a percentile and a z-score using the CDC 2000 stature-for-age charts, which cover boys and girls aged 2 to 20, and shows the range of heights from the 5th to the 95th percentile for the child’s age.
A percentile is a position, not a grade. A child at the 10th percentile who has been there for years is following a healthy curve.
How to use the child height percentile calculator
- Choose the child’s sex.
- Enter the age in years, using a decimal for months (for example 9.5 for nine and a half).
- Enter the standing height in centimetres, inches or feet.
- Read the percentile, z-score and range. The 5th to 95th percentile heights show where most children fall.
Height percentile formula (the LMS method)
Percentile = Φ(z) × 100
Height at a given z: M × (1 + L × S × z)1/L
L, M and S are the skewness, median and coefficient of variation in the CDC tables for each age in months and sex; the calculator interpolates between ages. Φ is the standard normal distribution. Source: Kuczmarski RJ et al., 2000 CDC Growth Charts for the United States: Methods and development, Vital and Health Statistics Series 11, No. 246, 2002.
Worked example
A boy aged 8 years 1.5 months (97.5 months) is 128.6 cm tall.
- At 97.5 months the CDC median for boys is M = 128.61 cm.
- His height equals the median, so z = 0.00 and the percentile is 50th.
- The 5th to 95th percentile range at this age is 119.2 to 138.4 cm.
CDC heights by age: 5th, 50th and 95th percentiles
| Age (years) | Boys 5th | Boys 50th | Boys 95th | Girls 5th | Girls 50th | Girls 95th |
|---|---|---|---|---|---|---|
| 2 | 81 cm | 87 cm | 93 cm | 80 cm | 85 cm | 91 cm |
| 3 | 89 cm | 95 cm | 102 cm | 88 cm | 94 cm | 101 cm |
| 4 | 96 cm | 103 cm | 110 cm | 94 cm | 101 cm | 108 cm |
| 5 | 101 cm | 109 cm | 117 cm | 100 cm | 108 cm | 116 cm |
| 6 | 107 cm | 116 cm | 124 cm | 107 cm | 115 cm | 124 cm |
| 7 | 113 cm | 122 cm | 131 cm | 113 cm | 122 cm | 131 cm |
| 8 | 119 cm | 128 cm | 138 cm | 119 cm | 128 cm | 138 cm |
| 9 | 124 cm | 134 cm | 144 cm | 123 cm | 133 cm | 144 cm |
| 10 | 128 cm | 139 cm | 150 cm | 127 cm | 138 cm | 150 cm |
| 11 | 132 cm | 144 cm | 156 cm | 132 cm | 144 cm | 156 cm |
| 12 | 137 cm | 149 cm | 162 cm | 139 cm | 151 cm | 163 cm |
| 13 | 144 cm | 156 cm | 169 cm | 146 cm | 157 cm | 169 cm |
| 14 | 151 cm | 164 cm | 177 cm | 150 cm | 160 cm | 171 cm |
| 15 | 157 cm | 170 cm | 182 cm | 151 cm | 162 cm | 173 cm |
| 16 | 161 cm | 174 cm | 185 cm | 152 cm | 163 cm | 173 cm |
| 17 | 163 cm | 175 cm | 187 cm | 152 cm | 163 cm | 174 cm |
| 18 | 164 cm | 176 cm | 188 cm | 152 cm | 163 cm | 174 cm |
| 19 | 165 cm | 177 cm | 188 cm | 153 cm | 163 cm | 174 cm |
| 20 | 165 cm | 177 cm | 189 cm | 153 cm | 163 cm | 174 cm |
Reading the result
- Between the 5th and 95th percentile includes 90 percent of children and is usually normal.
- Tracking matters. Compare with earlier measurements; crossing two major percentile lines is the signal to check.
- Parents’ heights count. The Child Height Predictor estimates an adult height target from the parents’ heights.
- Weight and height together. Use the Child Weight Percentile Calculator and Child & Teen BMI Calculator.
This page is for information only and is not medical advice. A single measurement does not diagnose a problem; growth is judged over time. Talk to your child’s doctor about any concern.
Sources
- Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC Growth Charts for the United States: Methods and development. Vital Health Stat 11(246), 2002.
- Centers for Disease Control and Prevention. Growth Chart Training: stature-for-age LMS parameters, 2–20 years.
Frequently asked questions
What does a height percentile mean?
It compares a child’s height with children of the same age and sex in the CDC reference group. A child at the 30th percentile is taller than 30 out of 100 children of that age and shorter than 70. It describes position, not health.
Which growth chart does this use?
The CDC 2000 growth charts, based on US national surveys from 1963 to 1994, which the CDC recommends for children aged 2 to 19 in the United States. The charts for under 2 years use the WHO standards; see the Baby Growth Percentile Calculator.
When should I worry about my child’s height?
Speak to a doctor if your child is below the 3rd percentile, has dropped across two or more major percentile lines, is growing less than about 4 cm a year after early childhood, or is much shorter or taller than parents would predict. Many healthy children are simply tall or short.
Why do children sometimes change percentile in puberty?
Children who start puberty early grow quickly sooner and may move up the chart, then slow earlier; late developers do the opposite. The charts do not account for pubertal timing, so some shifts are normal.
How should I measure height?
Stand barefoot against a wall with heels together, back straight and eyes level. Mark the top of the head with a flat object and measure to the floor. Measure at the same time of day, because height can vary by a centimetre or so through the day.