There is no magic height predictor tool to tell you exactly how tall your children will be when they’re older. But you can get a good idea by using one of three methods to help predict your child’s future height.
There are three main height predictor methods you can use to estimate how tall your child will be:
Two Years Times Two: 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.
None of these height predictor methods are perfect. Determining a child’s future height unfortunately isn’t as easy as determining their gender. But any height predictor method 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 against each other.
More importantly, these height predictor methods are also 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. 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
The “two years times two” height predictor method is as simple 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, and there is no research to back up its accuracy.
Using the “two years times two” height predictor method:
Figure out how tall your child is or was when she was two years old.
Multiply that height by two.
The result is her predicted height.
For example, if your daughter is 32 inches tall when she is 2 years old, it is possible for her to be 64 inches (5 feet 4 inches) tall as an adult. The equation is: 32 inches x 2 = 64 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
The “follow the curve” height predictor method is another easy way to predict your child’s 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.
Using the “follow the curve” height predictor method:
Measure your child’s current height.
Plot it on the growth curve.
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
Of all the height prediction methods, this is the most accurate and consistent height predictor. 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.
Using the “genetic potential” height predictor method:
Record the genetic mother’s height.
Record the genetic father’s height.
Average the two heights together.
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 accurate is this method? Not very. But it’s better than nothing: 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.