Child Height Prediction Calculator

Calculator inputs

Use metric values or switch to imperial mode. In imperial mode, enter total inches for heights and pounds for weight.

Unit system

Child name (optional)

Child sex

Age (years)

Current height (cm)

Current weight (kg)

Mother height (cm)

Father height (cm)

Current height percentile

Puberty timing

Example data table

Example	Sex	Age	Current Height	Mother Height	Father Height	Percentile	Blended Prediction	Likely Working Range
Sample child	Girl	10.0 years	138.0 cm	163.0 cm	176.0 cm	60th	161.6 cm	157.6 cm to 165.6 cm

Formula used

1) Mid-parental genetic target

For boys: (Father Height + Mother Height + 13) / 2
For girls: (Father Height + Mother Height - 13) / 2

2) Genetic target range

Genetic Target ± 8.5 cm

3) Current growth projection

Current Height / Estimated Adult-Height Fraction For Age And Sex
The calculator uses an age-based fraction table to estimate how much of adult height is already reached.

4) Percentile-guided estimate

Genetic Target + ((Percentile - 50) × 0.18)

5) Final blended prediction

(Genetic × Weight 1) + (Current Projection × Weight 2) + (Percentile Estimate × Weight 3)
The weights shift with age, giving more influence to current growth as the child approaches adulthood.

How to use this calculator

Choose metric or imperial mode.
Enter the child’s age, sex, height, and weight.
Enter mother and father heights.
Add the current height percentile if known.
Select puberty timing for a small maturity adjustment.
Click Predict height to view the result above the form.
Review the blended estimate, working range, and graph.
Use the CSV or PDF buttons to save the output.

FAQs

1) Is this calculator medically exact?

No. It gives an educational estimate using parent heights, current growth, and percentile input. A pediatrician can assess bone age, growth velocity, hormones, and medical history for deeper accuracy.

2) Why does the calculator show a range?

Growth is not perfectly predictable. Nutrition, sleep, genetics, puberty timing, illness, and measurement differences can shift final adult height. A range is usually more realistic than one exact number.

3) What percentile should I enter?

Use the child’s current height percentile from a reliable growth chart or clinical record. If you do not know it, entering 50 gives a neutral midpoint assumption.

4) Why does puberty timing matter?

Early or late maturation can slightly change growth patterns. This calculator applies only a small adjustment, because true puberty effects vary widely between children and need clinical interpretation.

5) Can I use imperial values?

Yes. Switch the unit system to imperial. Enter heights as total inches and weight in pounds. The calculator converts everything internally before running the prediction.

6) Why include current weight?

Weight is shown for context and reference BMI. The main height estimate relies more heavily on age, sex, current height, parent heights, percentile, and puberty timing.

7) When should parents seek professional advice?

Consider medical review if growth seems unusually slow, very fast, far below family patterns, or linked with delayed puberty, chronic illness, poor appetite, or other concerning symptoms.

8) What is the blended prediction?

It is the final estimate created by combining the genetic target, current growth projection, and percentile-guided estimate. The weighting changes with age to keep the result balanced.