When Do Boys Stop Growing? Growth Spurts and Puberty

One minute they’re babies; the next they’re heading off for college.

They grow up so fast! But when do boys stop growing?

We dive deep into genetics, lifestyle, and the complex world of male puberty to give you the answer as your boy masters new heights.

Read on to learn more about how boys grow in height, when do they reach their limit, and what are the signs of a growth spurt.

In this article: 📝

When do boys stop growing taller?

Whether we like it or not, puberty comes for us all and your little boy is no different.

And it is the age they enter this stage that determines when they will stop growing.

The rate this happens, however, can be a little harder to pin down but it’s a good indicator of when you can expect your boy to stop growing.

Generally speaking, boys tend to fall into the ‘early bloomer’ or ‘late bloomer’ category.

Early bloomers may start to notice changes in their bodies as early as age 10, whereas late bloomers may start at age 14.

Of course, these changes could easily fall anywhere in between.

Boys who entered pubertal development at 12 can expect to reach peak growth acceleration between 13 to 15 (although some boys start puberty as early as 9). [1]

Those who started on the later side, can expect to keep reaching new heights until the age of 18.

What are the main signs of puberty in a boy?

It’s no secret that puberty has a significant effect on male growth, as well as the development of facial hair and a lower voice — none of which are particularly subtle.

We can thank those rising levels of testosterone.

But puberty has many stages, each of which brings its own challenges and confusion.

This huge transformation can be equal parts exciting, terrifying, and emotional for your adolescent boy.

All the more reason to know the stages of male puberty so you can better help them navigate the unexpected:

Physical changes

Puberty begins with the enlargement of the testicles and scrotum.

At this stage, boys will start to experience more erections which may also include wet dreams at night.

No need for embarrassment, this is a solid sign a growth spurt is en route.

Hair growth

Pubic hair begins to grow, followed by underarm and facial hair.

You may even notice hair on the arms and legs.

Deepening voice

The famous voice cracks appear as your boy goes from a soprano to a baritone (try to keep mimicking and giggling to a minimum).

Change in body composition

Perhaps the highlight of any growing young man is the increase in muscle size.

This is usually more noticeable in the mid-teens but boys can start to appear heavier just before puberty begins.

Breast development

While it may surprise your kiddo, a common part of male puberty is the development of breast tissue.

It’s usually down to a hormonal imbalance called gynecomastia, where the testosterone has converted to estrogen. [2]

Not to worry, this tends to resolve itself within one to two years.

Discussing sensitive topics during puberty

Adolescence is a very troubling time for young men and they will be confronting many body issues.

With locker room talk and romantic interests, young men may have concerns about their muscles, body hair or genitals.

And they may have a harder time coming to you with these worries — after all, no one feels more misunderstood than a teenager.

It’s not easy for parents to talk about bodily changes with their growing children but it is important and the benefits far outweigh the initial awkwardness.

To help you get through any questions your son may have, we answer them here for you first:

When do boys’ penises stop growing?

This is hardly the type of question that a young man will ask his mom, but kudos to you if he feels comfortable enough!

If you’re sitting down and having that ‘birds and the bees’ talk, you can subtly assure him that this can carry on until the age of 18.

Of course, it’s probably best for him to consult with a male figure in his life, but try to encourage him not to fall into any comparison pitfalls — this could lead to bullying or insecurity.

When do boys develop chest hair?

Unlike other direct indicators of puberty, chest hair can take longer to develop — with some men not seeing any until age 20.

If your son is concerned that he doesn’t have any chest hair, you can reassure him this could be down to genetics.

For example, those with naturally higher levels of testosterone have hairier chests, so if his father wasn’t hairy, he may not be either.

Be warned, this may trigger the follow-up question “when do men stop growing?”

When do men grow beards?

Beard growth in men parallels with chest hair growth — it is generally related to testosterone, and some men may struggle to grow a beard at all.

Remind your son that either way is perfectly normal, and stress the importance of a good grooming routine!

Wherever or however your talk takes place, we encourage the use of scientifically correct terminology.

Bodies are beautiful, fascinating and above all natural.

Getting you and your boy comfortable with the lingo from the outset takes the stigma out of essential conversations and avoids any potential misunderstandings.

When do boys get a growth spurt?

In the midst of this rapid hormonal and physiological change, your boy is gathering inches and fast — which most are only too happy about.

Boys generally tend to develop around two years later than girls, so you might notice a growth spurt between the ages of 12 and 15.

Turns out the playground talk that girls mature faster than boys is actually true!

So if you’re wondering why your little man suddenly can’t fit into his pants, it’s down to a ‘growth spurt’ mama.

At an increase of around three inches in this critical stage, they’ll be towering over you in no time (eep!)

Wait, so how many growth spurts do boys have?

Leading up to age 10, you may see growth spurts of around 2 inches per year.

And while we can’t give you a definitive number, there are some things you can look out for to identify if a growth spurt is in the works:

• Increase in appetite
• Sleeping more than usual
• More accident-prone (blame that shift in center of gravity)
• Weight gain
• Pants are shorter on the legs

Does genetics really affect height?

Genetics has a huge role to play in when men stop growing.

Studies suggest that hereditary characteristics make up for about 80% of your son’s growth patterns, while the other 20% comes down to environmental factors.

You can generally try to average out your son’s full height by comparing the parents.

Start by adding Mom and Dad’s heights together, then divide by two.

For males, add a further 2.5 inches, and you’ll have a reasonable guess.

It’s not an exact science though, and environment does play a part!

How do you trigger a growth spurt?

You might find yourself crying, “when do boys stop growing?!” as you reach into your purse for yet another pair of jeans.

But don’t forget – this can be a very sensitive time for young men.

As testosterone starts to develop, men may feel more competitive around their male peers, while adolescence is prime for teenage angst (remember those days?). [3]

If your little man is worried about his height, there are some gentle lifestyle factors you can introduce.

You might have other concerns — such as when do boys’ feet stop growing — but this all runs in parallel with their height, so some lifestyle changes may help.

Broach the topic sensitively with your little guy and suggest things such as:

• Eating a balanced diet: Think plenty of fresh fruit and vegetables, wholegrains, protein, and dairy
• Increasing their protein consumption: Chicken and milk for the win!
• Getting enough sleep: Between 8 and 11 hours during puberty (we doubt you’ll have trouble convincing your kid of this one).
• Staying active: Encourage your son to try stretching exercises like yoga
• Practicing better posture: Difficult in the computer age, but not impossible!

Can a 17 year old boy still grow?

While 16 is considered the average cut-off point for growth in most males, it’s not a guarantee. In particular, if your son is a late bloomer, you may notice growth of up to an inch.

When do men stop growing?

Never mind 17 – what about 18 and after?

By age 18, the majority of young men stop growing as their ‘growth plates’ will have fused by this point.

A growth plate is a layer of cartilage found on either end of the longest bones in your son’s body — so they reach a certain point and stop. [4]

However, growth delays can happen and it is not entirely impossible for a young man to continue growing even up to until age 20.

So, can a man still grow after 21?

Growing after 21 is extremely rare, but again, not impossible.

Don’t forget that growth isn’t always about height.

Young men are still developing mentally through puberty and beyond.

In fact, research suggests that the brain doesn’t develop fully until age 25.

Better still, men’s muscles don’t stop growing – if you’ve got a budding Mr. Universe on your hands, he’ll be delighted to know that peak muscle mass can develop as late as age 30!

What happens if a boy starts puberty earlier?

Puberty can begin as early as nine which can be quite alarming to your little man, especially if none of his friends are sharing the same timeline.

If your child is an early bloomer, here are a few things you can do to ease their mind:

Talk it out in a safe environment

For a child on the cusp of adolescence, being in any way different from their peers can feel traumatic.

We look to others to reassure ourselves that our experiences are normal and nowhere is this more important than when experiencing rapid physical and emotional changes.

Providing a safe space for your child to share their worries and fears is one of the best things you can do as a parent — brownie points if you come with knowledge at hand.

Talk to your GP

If your child is showing signs of being an early bloomer before 9, you may be dealing with precocious puberty. [5]

Precocious puberty happens when the brain hormone controlling reproduction is released too early, causing your little one to reach sexual maturity at a younger age.

There are many factors that can contribute to this, including hormonal disorders, genetics, and brain abnormalities.

There are treatments in place for precocious puberty so best to talk to your healthcare provider as soon as possible.

Reassure, reassure, reassure

Puperty, growth spurts, and bodily changes are not easy.

And let’s not forget navigating friendships, school, and first crushes.

Being there to reassure your growing boy that the changes he is going through are both normal and sure signs that manhood is on the horizon is the best move you can make as a mom.

This includes being open to lending hygiene advice, a safe haven, and gentle guidance for their greatest upheavals.

Remember, you are not alone.

Same goes for your not-so-little boy.

Need more advice on raising your teen?

If your little guy is going through these changes in life, it can be just as much of a struggle for you.

For support, guidance, and advice from other mamas, join Peanut.

Find out more about when girls stop growing and get your daughter in on the conversation early.