Boys come in all different shapes and sizes. No matter how broad the spectrum is for normal growth, a parent's most common question is, "What size should my son be?" Parents worry whether their son is too small to make the dean's list. They question whether their son too small to play basketball. These questions have led to the development of growth charts so that doctors can assess children's height and weight accurately.
Doctors use a growth chart to evaluate and keep track of children's growth. Often times there is a variation in an average boy's progress. Growth charts were developed by measuring and weighing thousands of children. These statistics were then broken up by sex and age. A curved line was then drawn. The curved line represents the 50th percentile, according to Kids Growth. The National Center for Health Statistics published two charts for boys, birth to 36 months, and 2 to 20 years of age.
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Comparing Growth Charts to Weight and Height
According to Kids Growth, a child should consistently be in the normal range for height and weight. This means that a boy should fall between the 10th and 90th percentile consistently throughout his lifetime. If a child fails to fall between the normal range, it is best to seek a doctor's advice.
Averages for Boys Birth to 36 Months
According to Keep Kids Healthy, at birth an average boy weighs anywhere from 3-10 lbs. and ranges from 18-21 ½ inches long. By 6 months, a boy has normally doubled in weight, and is between 25 and 27 ½ inches long. By 1 year old, the normal size for boys is 20 to 27 lbs. and 28 to 31 inches in length. At 2 years old, the range for a normal boy begins to widen, developing a larger discrepancy between the 10th percentile and 90th percentiles. At 3, a boy should weigh between 27 ½ to 36 ½ lbs., and his height is between 35 to 39 inches.
Averages for Boys 3 to 18 Years Old
Keep Kids Healthy cites that at 5 years old, the normal weight for a boy is between 30 to 45 lbs. The ordinary height for a 5-year-old is 40 to 45 inches. At 10, the range grows and the variation is 50 lbs. A normal 10-year-old boy weighs between 40 to 90 lbs. His height is between 50 and 58 inches. At 15, a boy should weigh between 100 and 160 lbs. He normally will be between 61 and 72 inches tall.
Factors that Play a Role in Growth
According to KidsHealth, puberty plays in important role in the growth of an adolescent boy. Once puberty begins, the change from a child to adult can take several years. Heredity plays a central factor in developing a boy's height and weight. A boy's race, ethnicity or nationality also will assist in deciding his stature. Lastly, eating habits contribute to a boy's height and weight.