3 Methods for Predicting Your Child's Height

Will your child be short, tall, or average? It's a question many parents ask, but there is no magic way to look into the future and see how tall your children will be when they grow up. You can get a good idea, however, by using a method that can predict your child's future height.

There are three methods you can use to estimate how tall your child will be:

Two Years Times Two Method

Simply double your child's height when he or she is two years old.

Follow the Curve

Use your child's current height and where they are on the growth curve at any age to predict their future height.

Genetic Potential Height Predictor

Predict your children's future height based on their genetic potential.

While none of the methods is perfect, any will be able to give you some idea of how tall your kids might be when they grow up. You can even use all three methods and see how they compare.

More importantly, these are helpful tools your pediatrician can use to spot when your kids aren't growing well. For example, if your child has the genetic potential to be 6 feet 2 inches, but is following a growth curve that will put him at 5 feet 6 inches, your doctor may want to investigate a possible cause for this. Many factors can influence your children's future growth, including their overall health and nutritional status as well as their genetic potential.

Two Years Times Two Method

Kids height
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The "two years times two" method for predicting your child's future height is as easy as it sounds. The drawback is that you need to wait until they are 2 years old or find the measurements you took then. This method has been used for a long time, though no research is available to back up its accuracy. 

To predict your child's height with this method:

  1. Figure out how tall your child is or was when she was two years old.
  2. Multiply that height by two.

The result is her predicted height.

For example, if your daughter is 34 inches tall when she is 2 years old, it is possible for her to be 68 inches (5 feet 8 inches) tall as an adult. The equation is: 34 inches x 2 = 68 inches.

The American Academy of Pediatrics points out that girls develop quicker than boys. Due to this, you might get a more accurate prediction for your daughter by using her height at 18 months.

Follow the Curve Method

Follow the Curve Height Predictor
Photo by Vincent Iannelli, MD

The "follow the curve" method is another easy way to predict your child's potential adult height. It relies on the standard growth charts used by pediatricians to monitor a child's development.

The current growth charts for children in the U.S. are available from the Centers for Disease Control and Prevention (CDC). There is a separate one for boys and girls and you will want to use the "Stature-for-age and Weight-for-age" charts.

To predict your child's height with this method:

  1. Measure your child's current height.
  2. Plot it on the growth curve.
  3. Follow along on their growth curve—staying in the same percentile—and see where they end up as an adult

The result is his predicted height.

For example, if your son is 43 inches tall at age 6 (the 10th percentile), then you could possibly expect him to be 66 inches (5 feet 6 inches) tall as an adult (the 25th percentile at 19 to 20 years old).

Genetic Potential Height Predictor

Sisters lined up to take their height
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Of all the height prediction methods, this is probably the most accurate. It considers the child's genetic potential based on the parents' average height. It's known as the mid-parental height method or the Tanner method.

To predict your child's height with this method:

  1. Record the genetic mother's height.
  2. Record the genetic father's height.
  3. Average the two heights together.
  4. Add 2 1/2 inches to that average if you are predicting a boy's height. Subtract 2 1/2 inches to that average if you are predicting a girl's height.

The result is your child's predicted height.

For example, if mom is 5 feet 2 inches (62 inches) and dad is 5 feet 8 inches (68 inches), the average is 65 inches or 5 feet 5 inches. The equation is: (62 inches + 68 inches) / 2 = 65 inches.

In this case, you might expect the kids to be:

  • Boys: 5 feet 7 1/2 inches
  • Girls: 5 feet 2 1/2 inches

How precise is this method? It's not, of course. The genetic potential height predictor has a 68 percent chance of being within 2 inches and a 95 percent chance of being within 4 inches of this predicted height.

Another limitation is that you have to know how tall a child's birth parents are for this calculation to work. This can make it impossible if you don't know the height of their genetic parents, as may be the case for adoptions or assisted fertility procedures with donor sperm or eggs.

A Word From Verywell

When your kids go through a growth spurt, you may wonder if they'll ever stop growing. It's fun to watch them grow, but it does bring up a few questions. While none of these height predictors is 100 percent accurate, they are interesting ways for you to gauge just how tall your kids might be.

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Article Sources
  • Centers for Disease Control and Prevention. Clinical Growth Charts. U.S. Department of Health and Human Services. 2017. https://www.cdc.gov/growthcharts/clinical_charts.htm.
  • American Academy of Pediatrics. Predicting a Child's Adult Height. HealthyChildren.org. 2016. https://www.healthychildren.org/English/health-issues/conditions/Glands-Growth-Disorders/Pages/Predicting-a-Childs-Adult-Height.aspx.