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When do boys stop growing?
Updated 13 October 2026 · Educational guide, not medical advice
Most boys stop growing between 16 and 18, though some grow a little into their late teens. Their fastest growth is typically between 13 and 14.
When boys grow fastest
Boys usually start puberty between 9 and 14. The first sign is normally growth of the testicles, which parents often don't notice. The growth spurt comes later in puberty than it does for girls, typically peaking around 13 to 14, when boys can grow 8 to 10 cm in a year.
That's why girls are often taller at 11 or 12. Boys start roughly two years later, but their spurt lasts longer and is bigger, so they usually overtake girls by 14 or 15.
Late bloomers
Some boys start puberty at 13 or 14 and can look small next to their friends for a while. This is very common and often runs in families. Late bloomers usually keep growing for longer, and many end up at an adult height that matches their parents.
A doctor can check bone age with a hand X-ray if there's any worry. It shows how much growing time is left.
Signs a boy is close to his adult height
- His voice has fully broken and settled.
- He's shaving regularly and has adult-pattern body hair.
- His height has changed very little over the last 6 to 12 months.
- His shoe size has stopped changing. Feet usually stop growing before height does.
Typical heights for boys in their teens
| Age | Average height (UK) |
|---|---|
| 10 | 139 cm (4'7") |
| 12 | 149 cm (4'11") |
| 14 | 163 cm (5'4") |
| 16 | 173 cm (5'8") |
| Adult | about 176 cm (5'9") |
These are approximate middle (50th centile) values from UK growth charts. Half of boys are taller and half are shorter. See the full table in our average child height by age guide.
How tall will my son be?
Parents' heights are the best single guide. A quick estimate for boys is (Dad's height + Mum's height + 13 cm) ÷ 2, give or take about 8.5 cm. Try our free height calculator for the range in cm or feet and inches.
What helps a boy reach his natural height
- Sleep: 8 to 10 hours for teenagers. Late nights on phones are the most common thing that cuts into this.
- Enough food: teenage boys in a growth spurt really do need more. Protein and calcium at every meal help.
- Activity: about an hour a day. Supervised strength training is safe for teens and doesn't stunt growth.
None of these will make a boy taller than his genes allow, but they help him grow to his own potential.
When to see a GP
- Signs of puberty before 9, or none by 14.
- He seems to have stopped growing early.
- He's dropping across growth chart lines or is much shorter than family members.
How tall will your child be?
Enter Mum's and Dad's heights for an estimated adult height range. Free, takes 10 seconds.
Try the height calculatorFrequently asked questions
Do boys grow after 18?
Most boys have reached their adult height by 18. A few, usually late bloomers, grow a little more, typically only a centimetre or two.
At what age do boys have their growth spurt?
Typically between 12 and 16, with the fastest growth around 13 to 14.
Does lifting weights stunt growth?
No. Supervised strength training is considered safe for teenagers and doesn't affect adult height.
More guides
Sources
- RCPCH: UK-WHO growth charts, 2–18 years
- NHS: Early or delayed puberty
- CDC: Growth charts
- Tanner JM, Whitehouse RH. Clinical longitudinal standards for height, weight, height velocity and stages of puberty. Archives of Disease in Childhood, 1976.
This guide is for general information only and isn't medical advice. If you're worried about your child's growth or development, speak to your GP or health visitor.