The short answer
Midparental height combines both biological parents’ heights and adjusts the average for a male or female growth-chart reference. Clinicians may use it as one piece of context when comparing a child’s measured growth pattern with family height.
Female reference: (mother + father − 13 cm) ÷ 2
Why the result needs a range
Even within the same family, adult height varies. Genetics involve many variants, and individual development is not captured by averaging two parent heights. A center shown without uncertainty looks more precise than the method really is.
GetTall therefore shows a broad ±10 cm reference around the family center. This width is intentionally easy to understand and broadly aligned with clinical target-height ranges described in the literature. A person can still finish outside it.
Regression to the mean
A 2024 analysis found that correcting for regression to the mean improved prediction: children of unusually tall parents were, on average, closer to the population mean than the uncorrected formula suggested, while children of unusually short parents tended to be taller than the uncorrected formula suggested. This is one reason a transparent basic calculator should not market its center as a precise final answer.
What the formula leaves out
- the child or teenager’s current height and age;
- several dated measurements and growth velocity;
- developmental and pubertal timing;
- measurement quality and time of day;
- health conditions, medication and skeletal maturity;
- population and family patterns beyond two parent heights.
How to use it responsibly
Use the number as a family baseline, not a goal and not a promise. If measured growth changes meaningfully, or you have a health concern, a pediatrician can interpret the full growth record and decide whether any evaluation is appropriate.
Keep the family estimate separate from a current height percentile: the two numbers answer different questions. See the full explanation in height percentile vs adult-height prediction.