A growth spurt is a period of rapid physical growth in height and weight that occurs during adolescence, marking the transition from childhood to adulthood. It is one of the most visible signs of puberty, driven by a surge in hormones that accelerate the body’s development. The growth spurt represents the final significant increase in height before reaching adult stature. The amount of height gained during this time is highly variable among individuals, but scientific averages provide a clear expectation for the potential increase.
When Growth Spurt Occurs
The timing of the adolescent growth spurt is closely tied to the onset of puberty, and this process shows a clear difference between sexes. On average, girls begin their growth acceleration earlier than boys. The onset of the pubertal growth spurt typically begins around age 9 in girls, with the period of fastest growth, known as Peak Height Velocity (PHV), generally occurring at a mean age of 11.5 years.
Boys experience a later growth phase, with the growth spurt beginning around age 11 and PHV usually reached at a mean age of 13.5 years. The entire period of intense pubertal growth usually lasts for two to three years. This difference in timing means that girls often appear taller than boys for a short period during early adolescence, before boys catch up and surpass them due to their later, generally greater, growth magnitude.
Total Height Gained During the Spurt
The total height gained throughout the entire pubertal phase is substantial and represents approximately 17% to 18% of a person’s final adult height. The most intense part of this growth is the Peak Height Velocity (PHV), which provides the highest rate of increase per year.
For boys, the total height gained during the growth spurt typically ranges from 10 to 12 inches (25 to 30 centimeters). Their maximum growth rate during the PHV averages around 3.5 to 4 inches (9 to 10.3 centimeters) per year. This velocity is generally higher than that seen in girls, contributing to the greater average height difference between adult males and females.
Girls generally experience a total height gain of about 9 to 11 inches (23 to 28 centimeters) throughout their pubertal growth phase. Their PHV, the fastest rate of growth, averages around 3 to 3.5 inches (8.3 to 9 centimeters) per year. Individual growth can fall outside these ranges due to varying genetic and environmental factors.
Key Factors That Influence Maximum Growth
The maximum height achieved is influenced by several interconnected variables. The most significant determinant of final height is genetics, which is estimated to account for 60% to 80% of the variation in adult stature. A child’s adult height potential is often predicted based on the average height of their parents, with the final height typically falling within a range of about four inches above or below that mid-parental average.
Adequate nutrition is necessary for achieving full growth potential. The rapid bone and tissue production during the spurt demands sufficient intake of specific nutrients. Protein is needed to build new tissues, while minerals like calcium and vitamin D are required for proper bone mineralization and structural strength.
Hormones are the direct chemical drivers of the growth spurt. Growth Hormone (GH), released by the pituitary gland, stimulates the production of Insulin-like Growth Factor 1 (IGF-1), which directly promotes the division and growth of bone cells. The sex hormones, testosterone and estrogen, also contribute to the acceleration of growth and are responsible for the differences in the timing and magnitude of the spurt between boys and girls.
The End of Height Gain: Growth Plate Closure
The process of gaining height comes to a definitive end when the growth plates in the long bones of the body fully mature. These structures, known as epiphyseal plates, are layers of cartilage located near the ends of the long bones, such as those in the legs and arms. Longitudinal bone growth occurs as the cartilage cells within these plates multiply and are gradually replaced by hard bone tissue.
The rising levels of sex hormones during puberty, particularly estrogen, signal the final maturation and fusion of these plates. Estrogen acts by accelerating the transformation of cartilage into bone. Once this cartilage is completely replaced by solid bone, the growth plate is considered “closed,” and no further increase in height is possible. Girls typically complete this closure process earlier than boys, reaching their final adult height around ages 15 to 17, while boys often continue growing until ages 16 to 18.