Boys typically stop growing in height around the age of 16, with most reaching full physical maturity by 18. However, the exact timing varies because puberty can start at different ages for each boy, usually between 8 and 14 years old. Boys experience their fastest growth spurt 1 to 2 years after puberty begins, and puberty itself can last 2 to 5 years. Some boys who start puberty later may grow faster for a shorter time to catch up. While most boys stop growing by 16 to 18 years, some rare cases show continued, though minimal, growth into the early 20s. This late growth occurs because growth plates in the bones, which allow lengthening, close at different times for different individuals. Once the growth plates have fused, growth in height stops. In summary:
- Most boys stop growing by age 16
- Full physical maturity usually reached by age 18
- Some rare cases continue minimal growth into early 20s
Growth in other areas such as muscles can continue into the 20s, but height growth mainly ends by 18.
