Height CalculatorFree online other calculator — instant results, no sign-up
Predict a child's adult height from parents' heights (mid-parental method).
About the Height Calculator
This calculator estimates a child's eventual adult stature based on the biological parents' standing heights using the mid-parental method. It is commonly referenced by parents and pediatricians to set a baseline expectation for adult growth.
- Child
- Biological sex of the child (Boy or Girl), which determines the 13 cm sex-adjustment factor.
- Mother's height
- Standing height of the biological mother measured in centimeters (typically between 120 and 210 cm).
- Father's height
- Standing height of the biological father measured in centimeters (typically between 130 and 220 cm).
Formula and method
For a boy: h = (m + f + 13) / 2 For a girl: h = (m + f − 13) / 2 Likely range = [h − 8.5, h + 8.5]
- hPredicted adult height in centimeters
- mMother's height in centimeters
- fFather's height in centimeters
The tool calculates the mid-parental height by summing the mother's and father's heights, adjusting by adding 13 cm for a boy or subtracting 13 cm for a girl, and dividing by 2. The likely range is determined by applying a margin of ±8.5 cm around the predicted target, with both results rounded to one decimal place.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- ChildBoy
- Mother's height165 cm
- Father's height180 cm
Results
- Predicted height179 cm
- Likely range170.5 – 187.5 cm
How to use the Height Calculator
- 1Select the biological sex of the child.
- 2Enter the biological mother's height in centimeters.
- 3Enter the biological father's height in centimeters.
- 4Apply the sex adjustment (+13 cm for boys, −13 cm for girls), divide by 2 for the prediction, and calculate the ±8.5 cm spread.
Reading your result
The predicted height represents the statistical midpoint of the child's genetic growth potential. The likely range (±8.5 cm) encompasses roughly the 3rd to 97th percentile spread for children born to those parents, reflecting natural polygenic variation.
Limitations
This mathematical estimation assumes typical nutrition, health, and hormone levels; it does not evaluate bone age, endocrine disorders, or chronic medical conditions. It also cannot account for adopted children or cases where parental heights were altered by environmental stunting.
Common questions
Why is 13 centimeters added for boys and subtracted for girls?+
Thirteen centimeters (approximately 5 inches) is the average worldwide adult height difference between biological males and females, allowing the calculation to equate parental genetics to either sex.
Why is the likely range set to ±8.5 centimeters?+
Adult height is a polygenic trait influenced by thousands of genetic variants. An 8.5 cm margin represents approximately two standard deviations above and below the mid-parental target, covering most sibling variations.
Can a child grow taller or shorter than the likely range?+
Yes. Environmental factors such as nutrition, physical activity, sleep, illnesses, or inheriting unusual combinations of tall or short genes can cause a child to fall outside the ±8.5 cm range.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.