Young peoples' bones stop growing by approximately age 20, somewhat earlier in women and somewhat later in men. Long bone growth, that is, in the arm, forearm, thigh, and leg, ceases later and smaller bone growth, that is, in the hands, feet, and spine, ceases earlier. In essence, you're as tall as you're going to be by your mid- to late teens, and at the latest, by approximately age 20 or so. Read more