How Tall Will My Child Be? Easily Calculate Your Child's Height

Will our child grow taller as they grow up? This is a question that parents often wonder and worry about because if a child continues to grow but their height remains the same, it not only signals that the child may not be developing appropriately for their age, but it also affects the child’s psyche when compared with peers of the same age. Therefore, accurately calculating your beloved child’s final height and understanding the various factors involved will help to understand the child’s growth and deal with problems in a timely manner

Factors affecting the child’s height

1. Genetics Normally, if the parents are tall, the child is likely to be tall, or if the parents are short, the child is likely to be short
2. Environment Includes appropriate nutrition, exercise, adequate rest, and normal functioning of the endocrine glands, such as Growth Hormone, Thyroid Hormone, and Sex Hormone, etc.

Normally, children have a standard rate of height increase as follows

***Moreover, it’s possible to roughly know the child’s final height in advance through estimation and predicting the adult height

Estimating and predicting the final height in adulthood

There are 2 main methods to estimate and predict the final height in adulthood as follows

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1) Calculating the final height from the parents’ height (Midparental Height and Target Height)

This is the height potential genetically. Parents can try to calculate their child’s approximate height using this method

Boys = (Father’s height + Mother’s height + 13) ÷ 2


For example
Father’s height = 175 cm, Mother’s height = 152 cm.
175 + 152 = 327 cm.
Add the result by 13, getting 327 + 13 = 340
Divide the result by 2, getting 340 / 2 = 170
170 centimeters is the approximate future height of the son

Girls = (Father’s height + Mother’s height – 13) ÷ 2

For example
Father’s height = 175 cm, Mother’s height = 152 cm.
175 + 152 = 327
Subtract the result by 13, getting 327 – 13 = 314
Divide the result by 2, getting 314/2 = 157
157 centimeters is the approximate future height of the daughter

***However, the possibility of the final height will be within a range of plus or minus 7 – 9 centimeters, so the son’s final height, according to the example, would be between 161 – 179 centimeters, and the daughter’s would be between 148 – 166 centimeters accordingly

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 2) Calculating the final height from X-ray photographs of bone age (Bone Age) (Predicted Adult Height)

We can know the bone age from an X-ray of the left hand, from the wrist to the fingertips, by comparing every bone’s growth with standard bone age X-ray photographs. The bone age tells us how much more a child can potentially grow, and doctors generally track the child’s development and growth using standard growth charts by sex and ethnicity, which include both height and weight compared to age. Parents can try to plot their child’s height and weight against these standard values

Growth standard charts for boys and girls

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Doctors can more accurately calculate the future height of children

Normally, doctors use information from both methods, calculating the final height from genetics alongside bone X-rays to determine bone age, which indicates how much more a child can potentially grow. Then, they analyze the final height together. The bone age does not necessarily have to match the actual age because other factors and hormones determine it, especially sex hormones. This method requires consultation with a specialist or a pediatric endocrinologist

Be wary of children growing too tall for their age

For children who grow noticeably taller than peers of the same age, be cautious as they might be at risk of developing precocious puberty, which causes children to grow rapidly at first and have bone ages more advanced than their actual ages. Then, bones close earlier than expected, making children who grew rapidly at first end up shorter in adulthood.

This condition, besides affecting height, also affects the mental state of the child, especially girls who often develop breasts before age 8 or have their first menstruation before age 9, which makes their body different from peers of the same age. In boys, it can be observed from the size of the testicles, which tend to be larger than 4 cc, for instance. If a child has this condition, they should see a doctor for treatment to delay puberty. The doctor will perform a bone age assessment and consider other factors such as hormones, genetic height, etc., to diagnose and evaluate treatment, including advising whether to administer drugs to delay bone closure to increase height, depending on the case.

If you suspect your child is growing too fast or too tall for their age, they can be examined and consulted with specialists in precocious puberty at the Pediatric Center, Bangkok Hospital, which has a team of doctors ready to diagnose and provide comprehensive care from birth to adolescence

• Article How to Maximize Adult Height by Suttipong Wacharasindhu from the manual of Health Promotion Foundations in Nursing Curriculum by the Health Promotion Foundation (THPF)