Child Sex Select sex Male Female Select the biological sex of the child

Father Height (ft and in)

Enter feet (3-8) and inches (0-11.9) separately (e.g., 5 ft 10 in)

Mother Height (ft and in)

Enter feet (3-8) and inches (0-11.9) separately (e.g., 5 ft 4 in)

Quick Examples:

Average Parents, Male Child Taller Parents, Female Child

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This calculator is a screening tool only, not a diagnostic instrument. It is not intended to replace professional medical evaluation. Consult a healthcare provider.

What Is Predicted Adult Height

Predicted adult height is an estimate of how tall a child may grow based on the heights of their biological parents. It uses a math formula that looks at the average of both parents and adjusts for whether the child is a boy or a girl. This number gives parents a general idea of a child's likely final height, but it is not exact. Many other things can affect how tall a child actually grows.

How Predicted Adult Height Is Calculated

Formula

This formula starts by adding both parents' heights together. For a boy, it adds 13 extra centimeters because boys tend to grow taller than the average of their parents. For a girl, it subtracts 13 centimeters because girls tend to end up shorter than that average. Then it divides by 2 to find the middle point. This method is known as the Tanner Method and is one of the most widely used ways to guess a child's adult height from family traits alone.

Why Predicted Adult Height Matters

Knowing a child's predicted adult height may help parents and doctors track growth over time. It gives a simple baseline to compare against actual measurements during regular check-ups.

Why Growth Tracking Is Important for Early Detection

When a child's measured height is much lower than the predicted range, it may point to a growth issue that a doctor can look into. Catching problems early may allow for sooner evaluation. On the other hand, a height far above the predicted range may also warrant a check-in. This tool is not meant to replace doctor visits but may serve as a helpful reference point between appointments.

For Boys and Girls

The sex of the child changes the formula because boys and girls follow different growth patterns. Boys generally have a longer growth period and tend to reach a greater final height. Girls often stop growing earlier, usually within a year or two after their first period. The 13-centimeter adjustment in the formula accounts for this general difference between the two sexes.

For Advanced Users

The Tanner Method is a simple formula that works well for large groups of people. However, it may be less accurate for any single child. Factors like nutrition, ongoing health conditions, and the timing of puberty can shift the final height by several inches. A doctor may use bone age X-rays or more detailed growth charts for a closer estimate when precision is needed.

Child Height Prediction vs Bone Age X-Ray

Height prediction calculators use only parent heights to make a guess. A bone age X-ray looks at how mature a child's bones are and may give a more personal estimate. The calculator is fast and free but less detailed. The X-ray is more exact but requires a doctor's order. They are different tools for different needs and should not be confused with each other.

Example Calculation

A family wants to estimate the adult height of their son. The father is 5 feet 9 inches tall and the mother is 5 feet 4 inches tall. The child is male.

First, both heights are changed to centimeters. The father is 175.3 cm and the mother is 162.6 cm. The formula for boys adds them together with 13 cm: 175.3 + 162.6 + 13 = 350.9. Then divide by 2 to get 175.5 cm. The range is 175.5 plus or minus 8.5 cm, giving 167.0 to 184.0 cm.

Predicted Adult Height: 69.1 in (175.5 cm). Height Range: 65.7 in to 72.4 in (167.0 cm to 184.0 cm).

This result means the child may reach about 5 feet 9 inches as an adult, with a likely range between about 5 feet 6 inches and 6 feet 0 inches. Parents may use this range as a guide when talking with a doctor about their child's growth at yearly check-ups. Actual height may fall outside this range based on diet, health, and other factors.

Frequently Asked Questions

At what age can I use a child height prediction calculator?

This calculator may be used at any age because it relies only on parent heights and the child's sex. It does not use the child's current height. However, the estimate stays the same no matter the child's current age, so it is most useful as a general guide rather than a precise forecast.

How accurate is the mid-parental height formula?

The formula gives an estimate that is typically within about 2 to 3 inches of the actual adult height for most children. It works best as a rough guide for large groups. For any one child, the real height may be higher or lower than the predicted value due to many factors the formula does not measure.

Does the Khamis-Roche method give better results than the Tanner Method?

The Khamis-Roche method uses the child's current height and weight along with parent heights, so it may give a more personal estimate. The Tanner Method uses only parent heights and is simpler. Both are commonly used, but neither is exact for every child.

Can I use this calculator if my child has a growth hormone condition?

This calculator uses a standard formula that does not account for medical conditions that affect growth. A child with a growth hormone issue may reach a different height than the estimate suggests. Consult a healthcare provider for a more tailored growth assessment in these cases.