how long does it take to grow an inch?
Height Growth Rates 0–12 months: Grows about 10 inches (25 cm) 1–2 years: Grows about 5 inches (13 cm) 2–3 years: Grows about 3 1/2 inches a year most children will double their birth height by 3–4 years of age. 3 years to puberty: Grows about 2 inches (5 cm) a year. Hair growth flourishes from a clean, healthy scalp.