When do boys stop growing?
The typical boy is close to done growing taller at 17 and has all but finished by 18. On the CDC growth charts the median boy reaches 98% of his age-20 height at 16 and 99% at 16 years 11 months, and from 16 years 10 months on he gains less than 1 cm (0.4 in) a year. Boys who start puberty later keep growing later. These are population figures, not a prediction for any one boy or medical advice.
Growth left, year by year
Enter an age to see the CDC growth-chart height for boys at each birthday up to 20. Add a height to follow that percentile line.
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Typical growth left
Enter an age and press Show growth left by year. Without a height the table follows the median (50th percentile) line.
Boys’ height by age: how much growing is left
We calculated this table directly from the CDC 2000 stature-for-age data for boys. It shows the median height at each birthday, how much the median rises in the following year, and how much of the age-20 height is already reached.
| Age | Median height | Gain in the next year | Share of age-20 median | 5th – 95th percentile |
|---|---|---|---|---|
| 8 | 127.9 cm (4′2″) | 5.6 cm | 72.3% | 118.6 – 137.6 cm |
| 9 | 133.5 cm (4′5″) | 5.1 cm | 75.5% | 123.6 – 143.9 cm |
| 10 | 138.6 cm (4′7″) | 4.9 cm | 78.4% | 128.0 – 149.7 cm |
| 11 | 143.5 cm (4′9″) | 5.5 cm | 81.2% | 132.2 – 155.3 cm |
| 12 | 149.1 cm (4′11″) | 7.0 cm | 84.3% | 137.1 – 161.6 cm |
| 13 | 156.1 cm (5′1″) | 7.8 cm | 88.3% | 143.3 – 169.1 cm |
| 14 | 163.8 cm (5′5″) | 6.1 cm | 92.6% | 150.3 – 176.7 cm |
| 15 | 169.9 cm (5′7″) | 3.6 cm | 96.1% | 156.4 – 182.3 cm |
| 16 | 173.5 cm (5′8″) | 1.8 cm | 98.1% | 160.6 – 185.4 cm |
| 17 | 175.3 cm (5′9″) | 0.9 cm | 99.1% | 163.0 – 187.0 cm |
| 18 | 176.2 cm (5′9″) | 0.4 cm | 99.6% | 164.2 – 187.8 cm |
| 19 | 176.6 cm (5′10″) | 0.2 cm | 99.9% | 164.8 – 188.3 cm |
| 20 | 176.8 cm (5′10″) | – | 100.0% | 165.0 – 188.5 cm |
How to read it: “gain in the next year” is how far the median line rises over the following 12 months. “Share of age-20 median” is the median at that age divided by the median at 20. The last column is the 5th to 95th percentile of height at that age. The CDC charts come from surveys that measured many different children once each, so they smooth out individual growth spurts: a single child’s fastest year is usually faster, and their slow-down sharper, than the median line suggests.
What the table says
- The fastest stretch of the median line is the 12 months starting at about 12 years 10 months, when it rises 7.8 cm.
- The median boy passes 95% of his age-20 height at about 14 years 8 months.
- Yearly gain on the median line drops below 2 cm at about 15 years 11 months, below 1 cm at about 16 years 10 months and below 0.5 cm at about 17 years 10 months.
- After the 18th birthday the median line rises about another 0.7 cm by 20. The CDC charts end at 20, so they say nothing about later ages.
Why the age is different from one boy to the next
Growth in height ends when puberty ends, and puberty does not start on a fixed birthday. According to the US National Institutes of Health, the physical changes of puberty typically begin in boys between ages 9 and 14. The American Academy of Pediatrics describes the growth spurt as arriving as boys move further into puberty, with its peak in the later stages. A boy who starts at 9 and a boy who starts at 14 can both be developing normally and still finish growing several years apart.
Height itself stops increasing when the growth plates, the areas of new bone growth near the ends of the long bones, harden into solid bone. Nemours KidsHealth puts this at around ages 15 to 17 in boys. Whether a particular boy’s growth plates have closed can only be seen on an X-ray read by a doctor, which is not normally done without a medical reason.
Signs that growth is slowing
The most direct sign is the measurement itself: the same person, measured the same way at the same time of day, a year apart. In the CDC data a yearly change under 1 cm is what the median line shows from about 16 years 10 months onward. A small yearly change does not prove growth has ended, and a calculator cannot tell you that. To see how much the typical boy of a given age still gains, use the tool above or Am I done growing?
When to talk to a doctor
- Puberty has not begun by age 14, or it began but is not progressing. MedlinePlus lists both as reasons to contact a health care provider, along with a slow growth rate.
- Signs of puberty appear before age 9, which the NIH defines as precocious (early) puberty in boys.
- Height has moved across percentile lines on the growth chart instead of following one. You can check a single measurement with the height percentile calculator, but the trend over several visits is what a pediatrician reads.
This page cannot tell whether any of these apply to a particular child. It only describes the reference data.
Common questions
- Do boys grow after 16?
- On the CDC charts, yes: the median line rises 3.3 cm (1.3 in) between the 16th birthday and age 20, most of it before 18.
- Do boys grow after 18?
- A little on average: the median line rises about 0.7 cm between 18 and 20. Individual boys who entered puberty late can have more left than the median.
- At what age do boys grow the fastest?
- The steepest part of the CDC median line for boys begins at about 12 years 10 months (7.8 cm in 12 months). An individual boy’s peak can come a few years earlier or later.
- How tall will he be when he stops?
- That is a different question from when. The height predictor estimates adult height from age, height, weight and the parents’ heights, and the how tall will I be quiz asks the same things one at a time.
- Is it different for girls?
- Yes, girls finish about two years earlier on the same charts. See when do girls stop growing.
Sources (web pages checked 2026-11-12): growth figures: Kuczmarski RJ, et al. “2000 CDC Growth Charts for the United States: methods and development.” Vital and Health Statistics 11(246), 2002; stature-for-age LMS data file from cdc.gov/growthcharts. Puberty age range and early puberty: NICHD (US National Institutes of Health): About puberty and precocious puberty. Growth spurt timing: American Academy of Pediatrics, HealthyChildren.org: Physical development in boys. Delayed puberty and when to contact a provider: MedlinePlus Medical Encyclopedia: Delayed puberty in boys. Growth plates: Nemours KidsHealth: Growth plate fractures (section “What is a growth plate?”).