Mid Parental Height Calculation: Predict Your Child’s Adult Height

Health & Growth Tools

Mid Parental Height Calculation

Estimate the adult height of a child based on the biological parents’ height. This method, also known as the Tanner method, provides a simple and effective genetic height prediction.

Father’s Height

Enter the biological father’s height.

Please enter a valid height.

Mother’s Height

Enter the biological mother’s height.

Please enter a valid height.

Unit of Measurement

Select the unit for the heights entered.

Child’s Gender

Select the biological gender of the child.

What is the Mid Parental Height Calculation?

The mid parental height calculation is a simple and widely used method to predict the future adult height of a child based on the heights of their biological parents. Also known as the “Tanner method,” it works by averaging the parents’ heights and then adjusting this average up for boys and down for girls. This adjustment accounts for the typical height difference between adult males and females. While genetics are complex and account for about 80% of a person’s height, this formula provides a reasonable estimate of a child’s genetic potential.

This calculation is a useful tool for parents who are curious about how tall their child might become. Pediatricians and endocrinologists also use it as a preliminary check to see if a child’s growth is following a path that’s expected for their genetic background. A significant deviation from the predicted height might warrant further investigation into other factors affecting growth.

Mid Parental Height Formula and Explanation

The core idea of the mid parental height calculation is to find a genetic midpoint and then adjust for sex. The adjustment value is typically 6.5 cm (or 2.5 inches), which represents half of the average height difference between adult men and women.

Formulas:

For a Boy: ((Mother’s Height + Father’s Height) / 2) + 6.5 cm (or 2.5 inches)
For a Girl: ((Mother’s Height + Father’s Height) / 2) – 6.5 cm (or 2.5 inches)

Variables in the Height Calculation Formula
Variable	Meaning	Unit (Auto-Inferred)	Typical Range
Father’s Height	The biological father’s adult height.	cm or inches	150 – 210 cm (59 – 83 in)
Mother’s Height	The biological mother’s adult height.	cm or inches	140 – 200 cm (55 – 79 in)
Mid-Parental Height	The direct average of the two parents’ heights.	cm or inches	N/A
Gender Adjustment	A fixed value added for boys and subtracted for girls.	6.5 cm or 2.5 in	N/A

Explore the impact of nutrition on growth for more context.

Practical Examples

Example 1: Calculating for a Boy

Let’s say the father is 182 cm tall and the mother is 168 cm tall.

Inputs: Father’s Height = 182 cm, Mother’s Height = 168 cm, Gender = Male
Mid-Parental Height: (182 + 168) / 2 = 175 cm
Gender Adjustment: +6.5 cm
Final Estimated Height: 175 cm + 6.5 cm = 181.5 cm

Example 2: Calculating for a Girl (in Inches)

Let’s say the father is 6’0″ (72 inches) tall and the mother is 5’5″ (65 inches) tall.

Inputs: Father’s Height = 72 in, Mother’s Height = 65 in, Gender = Female
Mid-Parental Height: (72 + 65) / 2 = 68.5 inches
Gender Adjustment: -2.5 inches
Final Estimated Height: 68.5 in – 2.5 in = 66 inches (or 5’6″)

How to Use This Mid Parental Height Calculator

Select Units: First, choose whether you will enter heights in centimeters (cm) or inches (in).
Enter Father’s Height: Input the biological father’s adult height into the designated field.
Enter Mother’s Height: Input the biological mother’s adult height into the second field.
Select Child’s Gender: Choose ‘Male’ or ‘Female’ from the dropdown menu. The calculation adjusts automatically.
View Results: The calculator instantly displays the estimated adult height. The results also show the mid-parental height before the gender adjustment for transparency. The chart provides a visual range, as most children fall within +/- 4 inches (10 cm) of this prediction.

Key Factors That Affect Mid Parental Height Calculation

While the mid parental height calculation is a great starting point, genetics only tell part of the story. Several other factors play a crucial role in determining a child’s final adult height.

Genetics (Beyond Parents): Height is a polygenic trait, meaning it’s influenced by many genes. A child can inherit “tall” or “short” genes from grandparents and other ancestors, which can cause their final height to differ from the parental average.
Nutrition: A balanced diet rich in protein, calcium, vitamin D, and other essential nutrients is fundamental for reaching one’s full genetic height potential. Chronic malnutrition during childhood can lead to stunted growth.
Hormones: Growth hormone (GH), thyroid hormones, and sex hormones (estrogen and testosterone) are the primary regulators of growth. Any imbalance in these hormones can significantly affect height.
Overall Health and Medical Conditions: Chronic illnesses, such as celiac disease, kidney disease, or severe arthritis, can divert the body’s energy away from growth. Certain genetic conditions like Marfan’s syndrome or Down’s syndrome also directly impact stature.
Physical Activity: Regular, moderate physical activity promotes strong bones and healthy growth. It also helps regulate weight, which can influence puberty timing and growth.
Sleep: The body releases growth hormone primarily during deep sleep. Therefore, consistent and adequate sleep is vital for optimal growth, especially during childhood and adolescence.

Understanding the role of genetics in height can provide deeper insights.

Frequently Asked Questions (FAQ)

1. How accurate is the mid parental height calculation?

It’s an estimation, not a guarantee. About 95% of children will have an adult height that is within 4 inches (10 cm) above or below the calculated mid-parental height. It’s best seen as a predictor of genetic potential.

2. Can I use this for adopted children?

The formula is based on the heights of the biological parents, as it is a genetic prediction. It would not be accurate if used with the heights of adoptive parents.

3. What if one parent is unusually tall or short?

The formula still works. However, a phenomenon called “regression to the mean” suggests that children of very tall or very short parents are likely to be closer to the average height than their parents are.

4. Why is there a separate calculation for boys and girls?

On average, adult men are about 13 cm (5 inches) taller than adult women. The formula adjusts for this biological difference by adding to the mid-point for boys and subtracting for girls.

5. Do environmental factors matter more than genetics?

Genetics are considered the most significant factor, accounting for about 80-90% of a person’s height. However, environmental factors like nutrition and health determine whether a child reaches the full potential set by their genes.

6. At what age does growth stop?

Girls typically stop growing around age 15-16, while boys stop growing around age 18-19. This can vary, as growth plates in the bones fuse at different times for different individuals.

7. Can I make my child taller?

You cannot change your child’s genetic potential for height. However, you can help them reach their maximum potential by ensuring they get proper nutrition, adequate sleep, regular exercise, and good healthcare.

8. What is the “bone age” method and how does it compare?

The bone age method involves taking an X-ray of a child’s hand and wrist to assess skeletal maturity. It is considered more accurate than the mid-parental height method, especially for children whose growth is advanced or delayed, but it requires a medical procedure.

Explore more of our health and wellness calculators to gain a complete picture of growth and development.