How Tall Will My Child Be? Height Predictor

Medically Reviewed on 6/17/2021
how tall will my child be
Learn how you can predict your child’s height by using these 5 methods

There’s no crystal ball that can tell you exactly how tall your child will be. The main factor that determines your child’s height is genetics, although physical activity can factor in to some extent.

You can get a good idea, however, by using a few formulas that may help you predict your child's estimated future height.

Here are five methods you can use to estimate how tall your kid may be when they grow up.

5 methods to estimate your child’s future height

1. 2 x 2 method (multiplier method)

This is a very easy method to predict the height of your child, although there’s no evidence to support its accuracy:

  • Measure the height of your boy when he is 2 years old and your girl when she is 1.5 years old.
  • Multiply the height by 2 and you get your child’s expected height.

For example: If your boy’s height is 3 feet at age 2, you can expect him to be twice that = 6 feet.

2. Khamis-Roche method

The Khamis-Roche child height predictor calculates your child’s future height by using parents’ height, child’s current height, child’s current weight, and child’s gender. It's the most accurate method of predicting a child’s height without determining the skeletal age.

For boys, the actual height may differ from the calculated height by 2.1 inches. For girls, it may differ by 1.7 inches. 

As this method was developed based on the heights of Caucasian children, it may not be as accurate for children of other ethnicities.

3. Mid-parental method (average height method)

The mid-parental child height formula uses only the parent’s height:

  • Add the mother’s and father’s height and divide the total by 2. The final value is called mid-parental height.
  • For a girl's future height, subtract 2.5 inches from the mid-parental height. For a boy's future height, add 2.5 inches to the mid-parental height.

The margin of error by this method is about 4 inches.

Since the height of your child will primarily depend on their genetic makeup, they may be taller or shorter than you or your spouse depending on their genes.

4. Bone age method

The bone age method involves taking an X-ray of your child’s left wrist, hand, and fingers. The images are then compared to the images in the standard atlas of bone development that show the age of the child’s bone and thus the child’s age. 

This is based on the fact that certain anatomical changes take place in a child’s bones every year. The changes stop and become permanent anywhere between ages 12-16 in girls and ages 14-19 in boys.

Using the skeletal age, a doctor may predict:

  • How tall the child will grow to be and at what age
  • At what age the child will enter puberty

This method also allows a doctor to diagnose conditions that result in extreme stature (extremely short or tall) or abnormal growth of the arms. These include:

5. Growth charts

Standardized growth charts help doctors determine whether a child is growing normally. Doctors will keep a track of certain factors in children, such as their height, weight, head size, and body mass index (BMI). Looking at the chart, they can tell you about the progression in your child’s height and provide an estimate as to how tall your child will be.

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Medically Reviewed on 6/17/2021
American Academy of Pediatrics. Predicting a Child’s Adult Height.

Hoecker JL. What’s the Best Way to Predict a Child’s Adult Height? Mayo Clinic.

Kids Health. X-Ray Exam: Bone Age Study.