# 3 Ways to Predict Height

Will your child be a basketball player or a jockey? The correct answer only time will tell. A person's height is determined by genetics (70%) and environmental factors (30%), such as nutrition and physical exercise. Due to the number of variables involved in this process, getting the exact size that a child will have in the future becomes an extremely difficult task. Thus, only predictions based on scientifically based methods remain, but which do not have any guarantee of veracity (they only present probabilities). Read this article to get to know some of them and satisfy your curiosity.

## Steps

### Method 1 of 3: Predicting a Child's Final Height Based on Parental Height

#### Step 1. Use Gray's method for unborn children and children up to four years of age

It consists of matching the heights of the parents according to the baby's gender and dividing the result by two.

• The method derives from a 1948 article by Horace Gray for the journal Child Development and remains widespread to this day.
• The margin of error is 10 centimeters more or less, which may seem like a large amount, but it represents precisely the difficulty of accurately predicting a child's height.

#### Step 3. For a female child, divide the parent's height by 13 and multiply it by 12 (thus getting 12/13 of the actual height)

For a boy, divide the mother's height by 12 and multiply it by 13 (13/12 of the actual height).

• For example, if the father of a female child is 1.75m, multiply that value by 12 and divide it by 13, giving an adjusted result of 1.62m.
• Likewise, if the mother of a male child is 1.60 m, multiply the value by 13 and divide it by 12, giving an adjusted result of 1.73 m.

#### Step 4. Add the adjusted height of the father or mother to the other's actual height

In the case of a female child, with a father 1.75 m (set to 1.62) and a mother 1.60 m, the sum is 3.22 m. For a male child, the sum is 1.75 m (height of the father) + 1.73 m (height of the mother adjusted), resulting in 3.53 m.

#### Step 5. Divide the sum by two to estimate the child's final height

Using the examples from the last step, the result for the female child is 3.22/2 = 1.61m. As for the male child, it is 3.53 / 2 = 1.77 m.

#### Step 6. Get the final forecast

Thus, a female child whose father is 1.75 m and the mother is 1.60 m, will probably reach 1.61 m tall. A male child with parents of the same height can reach 1.77 m.

• Formulas: ((1.75 x 12/13) + 1.60) / 2 = 1.61 [female child]; (1, 75 + (1, 60 x 13/12)) / 2 = 1. 77 [male child].
• There are some websites that do these calculations for you, just enter the necessary heights.
• Also remember that, due to the margin of error of this method, the female child in the example above can reach between 1.51 and 1.71 m, depending on genetic and environmental factors.

#### Step 7. Use simpler variations if you prefer

There are modifications to Gray's Method that ignore the 12/13 adjustment in parental height. In this way, you simply add the heights, divide the result by two and add (boy) or subtract (girl) 8 or 12 centimeters. The predictions obtained are similar to those of the original method.

• Thus, for a female child, we get ((1, 75 + 1, 60) / 2) - 0, 08 = 1, 60 m or ((1, 75 + 1, 60) / 2) - 0, 12 = 1.56 m.
• For a male child, we get (((1, 75 + 1, 60) / 2) + 0, 08 = 1, 76 m or ((1, 75 + 1, 60) / 2) + 0, 12 = 1.80 m

### Method 2 of 3: Predicting Final Height Based on a Child's Current Height

#### Step 1. Double the height of a female child at 18 months or a boy at two years

This is probably the simplest method possible, which is based strictly on the child's height as an infant.

• For example, a female child of 80 cm and 18 months is expected to reach 1.60 m. On the other hand, a male child with 90 cm at two years of age can reach up to 1.80 m.
• This method also has a margin of error of 10 cm plus or minus.

#### Step 2. Use the Khamis-Roche Method

This method is derived from a 1994 journal article and relies on a more complex scale of equations based on six factors: child's sex, mother's height, father's height, child's height, child's weight, and child's age.

• This method is recommended for children over four years of age.
• Unless you really want to test your math skills, use a website that performs this calculation for you.
• For example, a 3-foot-tall, 20-kilogram, four-year-old female child with a 6-foot-tall mother and a 6-foot-tall father is likely to reach 6 feet.
• The margin of error for 90% of cases in this method is approximately five centimeters. Therefore, 90% of children with the above criteria will reach a height between 1.55 m and 1.65 m.

#### Step 3. Obtain the child's “bone age” from an x-ray

This method originated in 1959 and has been updated several times over the years. It involves taking an x-ray of the child's left hand, including fingers and wrist, to obtain bone age. Then, the value found must be compared with the child's chronological age.

• It is not possible to perform this procedure at home, through a computer, like the others. So if you are interested, see your child's doctor.
• This method is considered to be slightly more accurate than that of Khamis-Roche.

### Method 3 of 3: Predicting the Final Height of a Child Eight Years Old or Over

#### Step 1. Use the “Lauren's Method” call for girls ages 8-16 and boys ages 9-18

The Khamis-Roche and bone age methods can also be used for children in this age group.

• Created in 2005, this method uses the child's gender, date of birth, date of testing, standing and sitting height, and weight.
• There are online calculators for this method too.
• For example, a female child, born on May 5, 2003, in a test carried out on May 5, 2015, when she was 1.60 m standing, 1.24 m sitting and 54 kg, could reach 1, 64 m.

#### Step 2. Control your expectations, even for older children

Even though the methods described above are used on teenagers who are approaching their final heights, the results will still not be 100% reliable. There are so many factors that influence a person's final height that no prediction method will ever be entirely accurate. Growth spurts vary in occurrence and duration, environmental factors can change, and so on. The only way to know for sure how tall a child will be when he grows up is to wait and see.