Height Calculator

Predict the height of your child by entering the child’s height and weight and the height of the parents. This calculator considers the parent’s genetics and the child’s height and weight to estimate a child’s adult height.

How to Predict a Child’s Adult Height

There are several formulas available to help estimate a child’s adult height and stature, and they vary in accuracy.

Child’s Height at Age 2 Method

By far, the easiest (and probably least accurate) way of predicting a child’s adult height is to double their height when they turn two years old. This is sometimes referred to as the two years times two method.

Keep in mind that boys will often be slightly over this number, and girls will typically be slightly lower due to slight variances in growth rates. This method usually works because children often reach their growth percentile that they will remain in at age 2.^[1]

Mid-Parental Height Method

A slightly more sophisticated method for predicting a child’s future height is called the mid-parental height method.

Height Prediction Formula

You can use the mid-parental height method formula to predict adult height like this:

• Add the mother’s height and the father’s height in inches
• If the child is a boy, add 5 inches (12.7 cm) to that measurement; if it’s a girl, then subtract 5 inches (12.7 cm)
• Divide the number by 2 to get an estimated adult height

It’s important to note that the mid-parental height method has a margin of error of roughly four inches (10 cm), so it’s considered to give a pretty rough estimate.^[2][3]

If you need to convert the child’s height from inches to centimeters, or vice-versa, try our height converter.

Growth Charts Method

One way to predict a child’s height is to use a growth chart such as one released by the CDC^[4] to predict how tall a child will grow.

Growth charts compare a child’s height and weight with other children that are the same age and consider what percentile the child is in for height to estimate growth.

The growth charts below show the average height for males and females aged 2-20.

The growth charts illustrate the different growth rates between boys and girls. Males continue growing for 2-3 years after females stop growing.

Girls have a steady growth rate with a final growth spurt that peaks around age 11-1/2 and tapers off by age 16. On the other hand, boys have a steady growth rate and a final growth spurt that peaks at age 13 and tapers off by age 18.^[5]

Bone Age Method

One method for predicting height is to measure the bone age of the child. This method accounts for the variance in growth between children of the same age.

Since some children grow faster than others, and some stop growing before others, measuring the child’s bone age may give a more accurate height prediction. By measuring the growth plates on the bones, a doctor can estimate their skeletal maturity, which is often different than the child’s actual age.

This method can be combined with the mid-parental height method to improve accuracy.^[6]

This method is generally preferred by pediatric surgeons that need to know when a child has finished growing. This method is more complicated than some of the others since it requires taking x-rays to check the growth plates.^[7]

The Khamis-Roche Method

The Khamis-Roche method relies on scaling factors and other equations based on the child and parents’ height to make its estimate. It considers the child’s height and weight and also the height and weight of the parents.

The Khamis-Roche method is especially useful for predicting the height of children with unusual stature for their age.^[8]
This method is only considered accurate for children over the age of 4.

This calculator uses the Khamis-Roche Method for children over 4 and the Mid-Parental Height Method for children under 4.

Every Child’s Growth is Different

Many factors contribute to a child’s growth, including genetics, environmental factors, nutrition, and health. Genetics play a major role in a child’s height and weight but do not completely determine how much a child will grow.

Some genetic conditions and endocrine disorders can also have an impact on growth. Marfan Syndrome, Simpson-Golabi-Behmel Syndrome, Beckwith-Wiedemann Syndrome, Sotos Syndrome, and homocystinuria are examples of syndromes that can cause excessive growth due to excessive hormone secretion during development.^[9]

Other conditions, such as Down Syndrome, can cause children’s growth to fall behind their peers and will be shorter on average in adulthood.^[10]

Diet and nutrition during development can also have a significant impact on growth and future height. Excessive nutrition at a young age can cause overgrowth and affect height; it can also contribute to obesity.

Every child is different and will develop differently as well. Some children stop growing sooner or later than others and experience growth spurts at slightly different ages.

Because of this, any prediction of a child’s height as an adult is only an estimate.