growth velocity

Growth velocity is how fast a child is growing, measured as centimeters of height gained per year. It is the speedometer of growth: where a single height tells you where the child is, velocity tells you where they are heading.

Velocity changes predictably with age. It is very high in infancy, settles to a steady pace of roughly five to six centimeters per year through mid-childhood, and then surges again during the pubertal growth spurt before tapering to zero as the growth plates fuse. Each phase has its own expected normal range.

Clinically, velocity is often more revealing than absolute height. A child who is short but growing at a normal velocity is usually fine, whereas a child of normal height whose velocity has fallen and who is crossing downward through growth-chart percentiles is sending an early warning, sometimes the first sign of growth hormone deficiency, hypothyroidism, or chronic illness.

A practical caveat is that calculating velocity requires accurate, consistent measurements separated by enough time, ideally at least four to six months, because short intervals and measurement error can create misleading swings. This is why careful serial plotting on a growth chart is the foundation of assessing a child's growth.