Family height · Target-height estimate
Mid-Parental Height Calculator
Enter both biological parents' adult heights and choose the boy or girl formula to calculate your child's mid-parental height estimate. You'll also see an approximate target-height range in cm and ft/in.
Free · no account · calculations run in the browser · heights are not saved as child health records
What this Mid-Parental Height Calculator shows
Mid-parental height provides a rough family-height reference based on both parents' adult heights. It is also commonly used as a family-based target-height estimate.
The result is not a guarantee of adult height, a diagnosis, or a target the child must reach.
Worked examples
With a biological father at 180 cm and biological mother at 165 cm, the boy/male formula gives a mid-parental height of 179.0 cm and an approximate range of 168.8–189.2 cm.
For the same parent heights, the girl/female formula gives 166.0 cm and an approximate range of 155.8–176.2 cm.
As a display-rounding check, a father at 180 cm and mother at 172.6 cm produce a boy/male result of 182.8 cm, displayed as 6 ft 0.0 in rather than 5 ft 12.0 in.
How mid-parental height is calculated
The boy/male formula is (father height + mother height + 13 cm) / 2. The girl/female formula is (father height + mother height − 13 cm) / 2. Equivalently, the parental average is adjusted by +6.5 cm or −6.5 cm.
What the approximate target-height range means
This page uses the AAP convention of center ±4 in. Four inches converts exactly to 10.16 cm and is displayed to parents as about 10.2 cm. The range is not a guarantee or individualized prediction interval, and other resources may use different conventions.
Why Metric and US units must give the same result
US heights are converted using exactly 1 in = 2.54 cm before the canonical 13 cm formula is applied. Some US references describe a 5-inch adjustment before averaging, but 5 in and 13 cm are not identical. This site uses one canonical 13 cm formula for both unit modes so unit choice cannot change the result.
How to measure parent heights
Use reliable, measured adult heights after growth is complete, preferably without shoes. Both biological-parent heights are required; avoid height in shoes, identity-document estimates, or guessed values.
A parent's current measured height may be below younger peak adult height because of age, spinal compression, or other height loss. This calculator does not correct for parental age, reconstruct an earlier peak height, or ask the user to add an arbitrary amount. If reliable clinical records from different times disagree, an appropriate professional should decide which record to use.
The calculator accepts 50–274.32 cm after canonical conversion only as a technical guard against obvious unit or entry errors. It is not a normal adult-height range and does not diagnose short stature, tall stature, skeletal disease, or genetic disease.
Mid-parental height versus current height percentile
Mid-parental height uses only the two biological parents' adult heights. The Child Growth Chart Calculator instead compares a child's current standing height with a CDC age- and sex-specific reference.
Why growth velocity and the growth curve matter
The Height Velocity Calculator compares height measurements from two dates. The Child Growth Chart Calculator helps review current measurements and reference positions. Serial measurements provide more information than this family-height estimate alone.
A child whose current height or growth trend differs from the family-height estimate is not diagnosed by this calculator. Review accurate serial measurements with a healthcare professional when there are concerns.
Limitations
The formula does not include the child's current height, age, growth velocity, puberty timing, bone age, health, nutrition, or other genetic factors. It is not Khamis–Roche, a bone-age prediction, a diagnosis, or a treatment tool.
The simple formula can have more regression bias when parents are very tall, very short, or differ greatly in height. A child may grow inside or outside the displayed approximate range.
Alternative clinical methods
RCPCH digital growth charts use parental height z-scores and a regression factor. That is a separate method and is not mixed into this calculator. Current-height prediction, bone-age methods, and Khamis–Roche are also outside this page.
The retained 2024 research source evaluates additional age-, sex-, and regression-related modeling. This calculator does not implement that experimental model or present it as the current AAP method.
Helpful context
Frequently asked questions
How do I calculate mid-parental height?
Choose the boy/male or girl/female formula, then enter the father’s and mother’s measured adult heights. The calculator returns the mid-parental height and an approximate target-height range. It is a rough family-height reference, not a promise of one child’s adult height.
How is mid-parental height calculated?
This page averages both biological-parent heights, then adds 6.5 cm for the boy/male formula or subtracts 6.5 cm for the girl/female formula. This is algebraically equivalent to adding or subtracting 13 cm before dividing the total by two.
What does the approximate target-height range mean?
The page applies the AAP ±4 in convention, exactly ±10.16 cm, around the center. It is an approximate family-height range, not an individualized confidence interval or guarantee.
Is this a precise prediction of adult height?
No. Current height, growth velocity, puberty timing, bone age, health, nutrition, and many genetic factors are not inputs. A child may grow inside or outside the displayed range.
Why are both biological parents’ heights needed?
The published formula is defined from the adult heights of both biological parents. If either height is unavailable, this calculator cannot produce the formula as specified.
Why does the formula ask for the child’s sex?
The historical formula provides separate boy/male and girl/female calculations using a +6.5 cm or −6.5 cm adjustment from the parental average. Choose the formula used in the child’s medical record.
Will cm and ft/in give the same result?
Yes. US inputs are converted exactly using 1 inch = 2.54 cm, and both unit modes then use the same canonical 13 cm formula. The selected unit only changes how the result is displayed.
What if the parents are very tall, very short, or very different in height?
Use reliable shoe-free adult measurements taken after growth was complete. A current measurement can be lower than younger peak adult height because of age, spinal compression, or other height loss. This calculator does not correct for parental age, reconstruct peak height, or apply regression, so do not add an arbitrary number of centimeters. If reliable clinical records differ, an appropriate professional should decide which record to use. The separate RCPCH z-score method and the 2024 experimental regression model are not implemented here.
Does the calculator use the child’s current height or age?
No. It uses only the two biological parents’ measured adult heights and the selected historical sex formula. It does not use the child’s current height, age, bone age, or puberty stage.
What is the difference between mid-parental height and a height percentile?
Mid-parental height describes family-height background. A height percentile compares the child’s current measured height with a reference for the child’s age and sex. They answer different questions.
When should growth be discussed with a healthcare professional?
Discuss concerns about current height, a slowing growth rate, changes across the growth curve, puberty timing, or health with a qualified healthcare professional. Accurate serial measurements are more informative than this estimate alone.
Does this site save the heights?
Calculator inputs are processed in your browser and are not saved as a child health record or sent to an external calculation service.
References
This page uses the canonical 13 cm center formula and the AAP ±4 in range convention. Different resources may use other ranges or regression methods; the RCPCH z-score regression method is not implemented here.
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Understand this result
What Is Mid-Parental Height?
Understand the family-height estimate and why it is broad context rather than a prediction.