Most people stop growing in height during late adolescence, typically when growth plates in the bones fuse. This process varies by sex, genetics, and health factors.

Girls' Growth Timeline

Girls usually experience their main growth spurt between ages 9.5 and 13.5, adding about 3.5 inches in the peak year. They generally reach adult height around 14-15 years old , or roughly 2-2.5 years after their first menstrual period, as puberty accelerates then halts long-bone growth. By age 16-18, growth fully stops for most.

Average heights by age (girls, approximate global averages):

Age| Height (inches/cm)
---|---
12| 59.4 / 151 1
13| 61.8 / 157 1
14| 63.2 / 160.5 1
15| 63.8 / 162 1
16+| 64 / 162.5 (plateaus) 1

Boys' Growth Timeline

Boys' growth spurt hits later, often ages 12-15, with rapid increases around 13.5 (up to several inches yearly). They typically stop around 16-18 years old , though some continue until 20-21 if puberty starts late. Full maturity by 18 for most, with growth plates fusing shortly after.

Key factors:

  • Puberty timing : Early starters may finish sooner; late bloomers grow longer.
  • Genetics : Accounts for 60-80% of height; parental heights predict outcomes.
  • Nutrition & health: Deficiencies or conditions (e.g., hormone issues) can delay or stunt.

Exceptions and Variations

Rarely, growth persists into early 20s (e.g., small spurts at 20-21), but not beyond as plates ossify. Disorders like gigantism allow prolonged growth until treated. Forum chatter, like Reddit teens worrying at 18, often reassures: many still add inches post-18 if plates are open (check via X-ray).

"Boys experience the fastest growth... around age 16 and reach full physical maturity by 18."

Real-Life Story

Imagine a boy hitting 5'5" at 15, fretting like that Reddit poster—yet family history showed his dad grew till 19. With good diet and sleep, he added 4 inches by 17. Always consult a doctor for personalized scans if concerned.

TL;DR : Girls ~14-15, boys ~16-18; varies individually—nutrition and genes matter most.

Information gathered from public forums or data available on the internet and portrayed here.