What is Genetic Height Prediction?

If a father is 175 cm and a mother is 165 cm, the predicted adult height range for their boy, according to genetic formulas, is approximately 171.5 to 181.5 cm. About 70% of a child's final height is determined by genetics. In medicine, "target height" is commonly used to estimate a child's genetic potential. One classic method is the mid-parental height method. Our calculator uses this widely referenced formula from pediatric clinics: For boys, predicted height ≈ (father's height + mother's height + 13) ÷ 2 ± 5 cm; for girls, predicted height ≈ (father's height + mother's height − 13) ÷ 2 ± 5 cm. The addition or subtraction of 13 cm accounts for the average systematic height difference between men and women, while the ±5 cm provides a fluctuation range of about one standard deviation, representing the interval where most children's adult heights will fall.

How to Use This Calculator

Select "Boy" or "Girl" under the "Child's Gender" option.
Enter the father's stable adult height in centimeters in the "Father's Height" input box. For example, if the father is 178 cm tall, enter 178.
Enter the mother's stable adult height in centimeters in the "Mother's Height" input box. For example, if the mother is 163 cm tall, enter 163.
Click the "Calculate" button, and the predicted result will instantly appear on the right or below. You will see a "Predicted Height Range" card displaying an interval like "Approx. 170.5 ~ 180.5 cm".
If you want to calculate another set, click the "Clear" button to empty the input boxes and start over from step 1.

Complete Example: Boy's Height Prediction

Let's look at a real example. Suppose the father is 178 cm tall, the mother is 165 cm tall, and the child is a boy.

Calculation Process:
Step 1: Plug the parents' heights into the boy's formula: (178 + 165 + 13) ÷ 2 = 356 ÷ 2 = 178 cm.
Step 2: Add the fluctuation range: 178 ± 5 cm, resulting in a lower limit of 173 cm and an upper limit of 183 cm.

Therefore, after entering "178" for the father's height and "165" for the mother's height, selecting "Boy", and clicking calculate, the result card will display a predicted range of Approx. 173 ~ 183 cm.

Interpretation: The central value of this boy's genetic target height is about 178 cm, and in most cases, his adult height will fall between 173 cm and 183 cm. If he is currently tracking within this channel, it generally indicates that his growth trajectory aligns with his genetic trend.

More Example Comparisons

Girl's Example: With the same parents, if the child is a girl, the formula becomes (178 + 165 − 13) ÷ 2 = 330 ÷ 2 = 165 cm. Applying the ±5 cm range yields Approx. 160 ~ 170 cm. You simply switch the gender to "Girl" in the calculator, keep the father's height at 178 and the mother's at 165, and click calculate to see this result.

What if the parents are shorter? If the father is 160 cm and the mother is 150 cm, the predicted central value for a boy is (160 + 150 + 13) ÷ 2 = 161.5 cm, with a range of Approx. 156.5 ~ 166.5 cm. Even if the parents are on the shorter side, the genetic upper limit may still exceed their average height, and there is still room for growth with adequate nutrition and exercise.

Exceptionally tall families: If the father is 195 cm and the mother is 180 cm, the predicted central value for a girl is (195 + 180 − 13) ÷ 2 = 181 cm, with a range of Approx. 176 ~ 186 cm. For tall families, the genetic potential for girls is equally significant.

How to Interpret the Results

The predicted result provides a range in centimeters, not an exact number. You can understand it as follows:

A range fluctuating 5 cm above and below the central value — The adult height of most healthy, well-nourished children will fall within this range.
If the child's current height is consistently and significantly below the predicted lower limit (e.g., more than 5 cm shorter than the lower limit), it may indicate growth retardation, and it is worth consulting a pediatrician or endocrinologist.
If the child's current height already exceeds the upper limit by a lot, it is not necessarily a problem, but conditions that cause advanced bone age, such as precocious puberty, should be ruled out.
This calculator reflects genetic potential. Actual height is also influenced by nutrition, sleep, exercise, illness, and endocrine factors. Therefore, the range is only a trend reference, not a medical diagnosis.

Typical Use Cases

Parents getting an initial idea of genetic potential: Many parents are curious about how tall their children will grow before they hit puberty. By opening the calculator and entering their own and their partner's heights, they immediately get a numerical range, giving them peace of mind and preventing blind anxiety.
Comprehensive judgment combined with growth charts: After a kindergarten or school physical examination, parents have their child's current height data and can compare it with this predicted range. If the current height percentile severely deviates from the predicted range, there is reason to conduct further bone age testing.
Comparative reference for multi-child families: If there is a brother and a sister in the family, entering the same parents' heights but switching the gender allows you to intuitively see the difference in genetic height potential between boys and girls, helping to set reasonable expectations for different children.

Common Misuses and Precautions

Common Misuses:

Treating the range as an absolute prophecy: Some parents see the predicted value and assume "the child will definitely grow to this exact height," ignoring the approximately 30% role of acquired factors. The prediction provides a probabilistic reference, not a promise.
Entering non-centimeter units: The calculator's default unit is centimeters. If you directly enter feet or inches, such as entering "6" for 6 feet, the result will be meaningless. Be sure to convert everything to centimeters before entering.
Using non-adult heights for calculation: If the parents themselves are still growing, or if they enter their height from when they were younger rather than their final adult height, the predicted value will be skewed. Please use the stable adult height values of both parents.
Using the predicted value to pressure the child: Using "you should grow to 180 cm" as a rigid target to pressure the child may negatively affect their mood and sleep, becoming counterproductive.

Precautions:

This tool only provides a linear estimation based on parents' heights and does not include clinical indicators such as bone age, growth rate, or stage of sexual development. It cannot replace a professional growth and development assessment.
For children with clear endocrine disorders (such as growth hormone deficiency or hypothyroidism), skeletal dysplasia, or chronic diseases, the reference value of the predicted result is very limited.
The calculation results depend on the accuracy of the input data. It is recommended to double-check before clicking calculate. If you enter negative numbers, 0, or obviously absurd values (like a father's height of 20 cm), the calculator's result will lose its practical meaning.
Our calculator performs all calculations locally in your browser. It does not collect or store any personal information.

Frequently Asked Questions (FAQ)

Can this prediction be completely trusted?
It should not be viewed as a precise prophecy. It reflects a genetic tendency range. Final height is influenced by multiple factors, including nutrition, exercise, sleep, and hormone levels. It is more appropriate to treat it as a trend reference.

Why does the boy's formula add 13 and the girl's subtract 13?
Because the average height difference between adult men and women is usually about 13 cm. By adding or subtracting half of this difference (i.e., 6.5 cm, which appears as 13 ÷ 2 in the formula) from the mid-parental height, the prediction can approach the genetic target height for the respective gender.

Must the input unit be centimeters? What if I use feet and inches?
This calculator only accepts centimeters. If your height data is in imperial units, please convert it first: 1 foot = 30.48 cm, 1 inch = 2.54 cm. Enter the converted values into the input boxes.

My daughter's predicted height is shorter than the mother's. Is this normal?
Yes, it's normal. If the father is on the shorter side, the median line of the family's genetic height will be pulled down. The girl's target height formula already accounts for the gender difference. If the result is shorter than the mother

Child Height Predictor Calculator