When Do Boys Stop Growing?

The age when boys stop growing depends largely on their puberty timeline. Experts explain what to expect, plus a few common height prediction methods doctors use.

Parents often wonder when boys stop growing, but there's not a set timeframe for when growing stops. Instead, the age boys reach their adult height varies from child to child. However, for many boys, growing ends before or around their 18th birthday.

Children naturally grow at different rates, and this is perfectly normal. However, there are some typical patterns that most kids follow. It's common knowledge that boys don't mature physically at the same pace as girls, but that growing gap isn't as wide before age 10.

Learn more about how boys grow in height, when they stop growing, and when they typically reach their final adult height. Additionally, we share three common height prediction methods used by pediatricians.

Editor's Note

While this article uses the terms "boy" and "girl," it's important to note that gender is a personal identity that exists on a spectrum, can change over the course of a person's lifetime—and most importantly—is something that a person defines for themselves. Sex, on the other hand, is assigned at birth based on the appearance of a baby's genitalia. While sex assigned at birth often matches a person's gender (called cisgender), sometimes, for transgender, intersex, and gender nonbinary people, it does not.

What’s the Average Boy Height?

According to the Centers for Disease Control and Prevention (CDC), the average height of adult men over 20 years old in the U.S. is 69 inches (5 feet, 9 inches). But that is just an average, meaning there will be boys who will be taller and boys who will be shorter when they reach their full adult height. Some boys will reach their full adult before age 17, while others may continue growing until age 20 or 21. They'll grow around 3 inches per year during puberty, which typically occurs between ages 9 and 14 for boys.

Note that most children who experience precocious (early) and delayed (late) puberty will develop normally—they'll just reach their ultimate height a little earlier or later than average. Interestingly, however, there is research that suggests that going through puberty earlier may lead to taller height attainment due to more potential years of rapid growth, particularly for kids that eat a diet rich in animal fat and protein.

The CDC Growth Chart for Boys (2–20 years old) provides a closer look at the average height of boys in the years leading up to reaching full adult height. Approximately half of boys are expected to be shorter and half will be taller than the median height (50th percentile) at each age.

CDC Stature-for-Age Growth Chart for Boys (50th Percentile)
Age (years) Median Height (inches) Median Height (centimeters)
8 50.4 in 128 cm
52.6 in 133.5 cm
10  54.5 in 138.5 cm
11  56.4 in 143.5 cm
12  58.7 in 149 cm
13  61.4 in 156 cm
14  64.6 in 164 cm
15  66.9 in 170 cm
16  68.3 in 173.5 cm
17  69.1 in 175.5 cm
18 69.3 in 176 cm
Data provided by the Centers for Disease Control and Prevention.

Factors That Influence Height for Boys

Height, just like every other physical trait, varies from person to person. To a certain extent, a boy's height as an adult is predetermined from birth. However, a variety of factors can influence how tall they will grow, according to the American Academy of Pediatrics (AAP). These factors include the following:

  • Genetics: Kids whose biological parents are shorter than average are more likely to end up short, while kids with taller biological parents are likely to be taller than average.
  • Genetic disorders: Genetic disorders such as Down syndrome, Cushing's syndrome, and Turner syndrome can influence height.
  • Growth hormone deficiency: Growth hormone deficiency, which is when the pituitary gland produces insufficient growth hormone, can stunt growth.
  • Medical conditions: Chronic medical conditions such as heart disease, lung disease, chronic stress, diabetes, kidney disease, cancer, celiac disease, or digestive tract conditions can all impact height.
  • History of malnutrition: Malnutrition during childhood can stunt growth, while nutrient-rich diets can promote growth and attainment of growth potential.
  • Medication: Some medications, such as stimulants like amphetamines (used to treat attention-deficit/hyperactivity disorder) or corticosteroids can impact height.

Some of these factors are within your control, however, others are not. If you have any concerns about potential factors that may impact your child's growth or adult height, check with their doctor.

When Do Boys Have Growth Spurts?

Boys will experience growth spurts periodically throughout their development, particularly during infancy, toddlerhood, and again in the tween and teen years. "Growth spurts aren't common in the 3–10 age range," explains Zoltan Antal, M.D., chief of pediatric endocrinology at New York-Presbyterian Komansky Children's Hospital and Weil Cornell Medicine. "Most prepubescent children grow 2 inches or 5 centimeters a year on average."

Girls do most of their growing at the start of puberty, which can be as early as age 8. They typically reach their final adult height around two years after their first period. Boys, on the other hand, experience peak acceleration of growth much later, usually between ages 13 to 15. They typically enter pubertal development around age 12 (though some "early bloomers" may start puberty at 9 or 10, says Dr. Antal). Some boys may start puberty a year or two later than average, as well.

According to the AAP, here are some early signs that your boy is starting to go through puberty:

  • Deepening of the voice
  • Development of pubic, facial, and/or underarm hair
  • Enlargement of testicles and scrotum
  • Getting acne
  • Increased body odor
  • Putting on a bit of weight or slimming down before rapidly growing in height, developing more muscle, and "filling out"

When Do Boys Stop Growing in Height?

The age at which children stop growing in height depends on their sex and other factors. Although male children get a later start compared to their female peers, they eventually catch up, and then some. Most girls stop growing taller by age 14 or 15. In contrast, after their early teenage growth spurt, boys continue gaining height at a gradual pace until around 18.

Note that some kids will stop growing earlier and others may keep growing a few years more. This variation is normal, but the average boy will stop growing by the end of high school. Essentially, when puberty stops, so does most of their growth.

Height Prediction Methods for Boys

While there's no 100% accurate way to determine how tall children will become in adulthood, there are three methods pediatricians commonly use to predict adult height for both boys and girls.

Research shows that while these methods (as well as others that have been developed) often produce valid estimates, they also have a wide range. This means that the estimate you end up with should be considered a possible height range spanning several inches rather than an exact expected height.

Accuracy of Height Prediction Methods

Future adult height estimates tend to be more accurate for healthy children in the middle height range. These tools may be slightly less accurate for shorter or taller children. Additionally, the various nutritional, medical, hormonal, or genetic issues that may impact a child's future adult height are not accounted for in these estimates. Your child's pediatrician can offer a more accurate height prediction as they will take all these factors into account when estimating your child's future height.

Mid-parental height calculator

Many doctors use what's known as a "mid-parental height calculator" to determine a range of how tall boys will grow to be, says Danton Kono, M.D., a pediatrician with Dignity Health Mercy Medical Group in California, though Dr. Kono is quick to add that the method is "still very inaccurate."

To get the estimated range, you take the boy's biological mother's height and add 5 inches, then average that number with the boy's biological father's height. The resulting height, plus or minus 3.35 inches, is how tall you can expect the boy to become. For instance, if their dad is 5'10" and their mom is 5'2", you would add 5'10" to 5'7" and divide that sum by two to get 5 feet 8½ inches. According to this method, the son should grow to be 5'8½", give or take a few inches.

Two times two method

The AAP recommends the "two times two" method. This simple approach starts with the toddler's height at age 2, then doubles it for a future adult height measurement. So, if your son is 2'11" at age 2, their predicted height as an adult is 5'10". The AAP notes, however, that "while this method has been around for a long time, no research exists to demonstrate its accuracy." However, it's an easy way to get a good rough estimate.

Growth chart

Dr. Antal prefers another method. "For a child who's going through puberty, you find their height percentile on a growth chart, and follow the corresponding curve out," he explains. For example, if you look at the CDC growth chart for boys 2 to 20 years, a 13-year-old boy who is 5'1" (61 inches tall) is in the 50th percentile. Based on that curve, they should reach an adult height between 5'9" or 5'10" (69–70 inches).

The CDC growth chart also shows weight-for-age percentiles that allow parents to estimate what their son might weigh in the future based on their current weight and age. Using the same example of the 50th percentile, a 13-year-old boy who weighs just over 100 lbs can expect to weigh roughly 155 by the time they're an adult if they continue developing at an average pace.

When to See a Doctor

If it seems like every other kid is growing but not your own, don't worry just yet. "Children with delayed growth, what's known as constitutional growth delay, experience slow and steady growth," says Dr. Kono. "In this scenario, even though a boy may not be maturing very fast, he's still going to be a 'normal' adult height."

However, if you have concerns about your child's growth, their pediatrician can do a bone age X-ray in the office to determine if your child's growth is on track. "If I get an X-ray of a 14-year-old boy and his bones look like those of a 12-year-old, that tells me he's still got five or six years of growth left and he won't achieve his final adult height until maybe even college age," says Dr. Kono.

However, if your son is falling off of the growth curve and not catching up with their peers, there could be something medically wrong, like a growth hormone deficiency, adds Dr. Kono.

"It's important to ask your pediatrician about where the child is in puberty and whether they are growing appropriately for their stage of puberty," says Dr. Antal. If you wait until your son is almost finished with puberty, there's not much an endocrinologist, a type of physician who specializes in conditions relating to hormones, can do to help.

Be sure to check in with your child's pediatrician if you have any questions or concerns about their growth. If treatment is necessary, growth hormone therapy can help boys reach their optimal height.

Key Takeaways

Typically, boys stop growing around age 18. However, when each individual child reaches their final height depends on a variety of factors including their personal puberty timeline, heredity, nutrition, and medical history.

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Parents uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Childhood Diet and Growth in Boys in Relation to Timing of Puberty and Adult Height: The Longitudinal Studies of Child Health and Development. Cancer Causes & Control. 2018.

  2. A Novel Method for Adult Height Prediction in Children With Idiopathic Short Stature Derived From a German-Dutch Cohort. J Endocr Soc. 2022.

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