Child Height Predictor
Predict your child's adult height from both parents' heights.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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This calculator uses the mid-parent height method to estimate your child's adult height. Here is how to use it:
- Select your units. Choose inches or centimeters. Heights entered in inches are automatically displayed in feet and inches as well.
- Enter both parents' heights. For accurate results, measure actual heights rather than relying on remembered values. Heights tend to be overestimated.
- Select the child's sex. The formula adjusts for the average 5-inch height difference between men and women.
- Read your results. The calculator shows the predicted adult height and a likely range of plus or minus 2 inches, which reflects the typical variation around the mid-parent prediction.
About the Child Height Predictor
The mid-parent height method is the most widely used simple formula for predicting a child's adult height. For a boy, the formula is: (father's height + mother's height + 5 inches) / 2. For a girl: (father's height + mother's height - 5 inches) / 2. The 5-inch adjustment reflects the average height difference between adult men and women.
Research suggests this formula is accurate within about 2 inches for approximately 68% of children. The remaining third will fall outside the 2-inch range. Factors like nutrition, health during childhood, and the height of more distant relatives can influence final adult height beyond what parents' heights alone can predict.
Frequently Asked Questions
How accurate is the mid-parent height prediction?
The mid-parent method predicts adult height within about 2 inches for roughly two-thirds of children. It is a reasonable estimate but not a guarantee. Genetics accounts for about 80% of height variation, but nutrition, health, and other environmental factors account for the remaining 20%. Children who experience chronic illness or malnutrition during growth may not reach their genetic potential.
At what age do children stop growing?
Most girls reach their full adult height by age 15-16, about 2-3 years after their first period. Most boys reach adult height by age 17-18, typically 2-3 years after puberty begins. Some boys continue growing into their early 20s. Growth charts can show a child's growth velocity over time and whether they are tracking toward their predicted height.
Can nutrition affect how tall my child grows?
Yes. Adequate nutrition is essential for reaching full genetic height potential. Protein, calcium, vitamin D, and zinc are particularly important for bone growth. Chronic undernutrition during childhood can permanently reduce adult height. In contrast, excellent nutrition in a genetically short child will not make them significantly taller than their genetic ceiling, but it ensures they reach it.
Is there a bone age test for more accurate height prediction?
Yes. A bone age X-ray of the left hand and wrist can assess skeletal maturity and provide a more accurate adult height prediction, especially for children with early or delayed puberty. This is done by a pediatric endocrinologist or radiologist. The Greulich-Pyle or Tanner-Whitehouse methods compare bone development to reference standards to estimate remaining growth potential.