What Is Mid-Parental Height?

Mid-parental height is a rough family-height reference calculated from the measured adult heights of both biological parents and a historical boy/male or girl/female adjustment.

The result includes a central family-height estimate and an approximate range around that center.

It is not the child’s current height, current height percentile, growth velocity, bone age, or a precise forecast of adult height.

A child may eventually grow inside or outside the displayed range. The result does not diagnose short or tall stature, identify the cause of a growth pattern, or determine whether treatment is needed.

Height is strongly influenced by inherited factors, so the measured adult heights of biological parents can provide useful family context when a child’s growth is assessed.

The mid-parental formula compresses that family information into one central estimate. The surrounding range provides a broad comparison area rather than an individualized prediction.

The center does not describe how tall the child should be at the current age and does not mean the child must reach that exact adult height.

A child’s current measurement, percentile trajectory, growth rate, maturation, health, and clinical findings remain separate information.

The estimate is most useful as one part of a broader growth assessment, not as a stand-alone conclusion.

This site uses the following canonical metric formula:

Boy/male center = (father height + mother height + 13 cm) ÷ 2

The same calculation can be written as:

Boy/male center = parental average + 6.5 cm

For a biological father measuring 180 cm and a biological mother measuring 165 cm, the parental average is 172.5 cm. Adding 6.5 cm gives a central estimate of 179.0 cm.

The formula uses measured adult heights. It does not use the child’s current age, height, growth curve, puberty stage, or bone age.

Choose the boy/male formula only when that is the historical formula used in the child’s medical record or clinical context. The calculator does not determine which formula is appropriate.

This site uses the following canonical metric formula:

Girl/female center = (father height + mother height − 13 cm) ÷ 2

The same calculation can be written as:

Girl/female center = parental average − 6.5 cm

For a biological father measuring 180 cm and a biological mother measuring 165 cm, the parental average is 172.5 cm. Subtracting 6.5 cm gives a central estimate of 166.0 cm.

The formula uses the same two parental-height inputs as the boy/male formula. Only the historical sex adjustment changes.

The calculator does not assess chromosomes, hormones, puberty, gender identity, skeletal maturity, or a medical condition. It only applies the selected historical formula.

The published formula is defined from the measured adult heights of both biological parents.

Use adult height measurements without shoes when available. A remembered or self-reported height may contain rounding or recall error, so a recent careful measurement is preferable.

If either biological-parent height is unavailable, this calculator cannot reproduce the formula as defined. Do not invent, substitute, or estimate a missing value solely to obtain a result.

Heights of adoptive parents, guardians, step-parents, or other relatives do not replace the two biological-parent variables in this particular formula.

That limitation describes the mathematical inputs of the published method. It is not a statement about parenthood, caregiving, or the legitimacy of any family relationship.

The traditional mid-parental method uses separate boy/male and girl/female formulas to account for average differences in adult height between the two historical reference groups.

The selected formula changes the parental average by +6.5 cm or −6.5 cm. It does not individualize the adjustment for puberty timing, hormones, skeletal maturity, or another biological characteristic.

Some references express the pre-division adjustment as 5 inches in US units and 13 cm in Metric units. Five inches equals 12.7 cm, so the two expressions are not exactly identical.

This site converts all US height inputs using exactly 1 inch = 2.54 cm and then applies the canonical 13 cm formula. It does not run a separate 5-inch formula.

Using one canonical formula prevents the selected display unit from changing the underlying result.

This site displays a range centered on the calculated mid-parental height.

Lower bound = center − 10.16 cm

Upper bound = center + 10.16 cm

The half-width of 10.16 cm is exactly 4 inches. It follows the AAP convention of showing mid-parental height plus or minus 4 inches.

The result is labeled an approximate family-height range because the simple calculation does not use child-specific measurements, maturation, bone age, health, or a statistical model fitted to the individual child.

The displayed range is not an individualized confidence interval, guarantee, diagnosis, or boundary that a child must remain within.

Other clinical systems may use different ranges, centiles, z-scores, or regression methods. Their outputs should not be mixed with this range as though they were the same model.

Mid-parental height uses only the measured adult heights of both biological parents and the selected historical formula.

A current height percentile compares the child’s measured standing height with children of the same age and sex in a defined reference.

The two results answer different questions. A child’s current percentile can be above, below, or near the family-height estimate without either result automatically being wrong.

Use the Height Percentile Calculator for the current CDC reference position and read What Does a Child’s Height Percentile Mean? for interpretation.

Neither one current percentile nor one mid-parental estimate can replace a series of accurate height measurements.

The term target height is sometimes used for mid-parental height, but the simple result should not be read as an exact destination.

This calculator does not use the child’s current height, age, earlier measurements, growth velocity, puberty timing, skeletal maturity, bone age, health conditions, medications, or nutrition.

It therefore cannot state that the child will become a particular number of centimeters or inches tall.

This page does not implement the two-years-times-two method, Khamis–Roche prediction, bone-age prediction, current-centile projection, or another adult-height model.

Even a clinical prediction that uses more information remains an estimate rather than a guarantee.

Adult height is influenced by many genetic variants rather than one single height gene.

Growth can also be affected by maturation, hormones, nutrition, medications, chronic illness, genetic conditions, skeletal conditions, and other health or environmental factors.

The mid-parental calculation does not measure any of those influences and cannot determine why a child is shorter or taller than the family estimate.

A difference from the center or range is not proof of disease, inadequate nutrition, parenting, or a problem with either parent’s height.

Do not use the estimate to start supplements, restrictive diets, hormone treatment, exercise programs, or other attempts to alter height.

Growth velocity describes how quickly height changed between two dated measurements. Mid-parental height contains no measurement dates and does not calculate a rate.

Puberty timing can also affect the current growth pattern. Children with similar family-height backgrounds may enter the pubertal growth spurt at different ages.

A child may temporarily be shorter or taller than peers because of maturation timing without the mid-parental formula being able to explain the pattern.

Read What Is Growth Velocity in Children? for an explanation of growth rates and use the Child Growth Velocity Calculator when two dated measurements are available.

A slowing or persistently unexpected growth pattern deserves clinical context, but one calculated rate or family-height estimate does not establish a diagnosis.

Bone age is an assessment of skeletal maturity, commonly based on an X-ray of the hand and wrist in an appropriate clinical setting.

A clinician may combine bone age with current height, age, growth history, puberty information, and other findings when evaluating growth or estimating remaining growth.

The Mid-Parental Height Calculator does not request, calculate, interpret, or predict bone age.

It also does not convert the family-height estimate into a bone-age-based adult-height prediction.

Do not obtain imaging, testing, or treatment solely because an online family-height estimate differs from a current measurement. Those decisions require an appropriate healthcare professional.

The simple arithmetic formula may be less representative when one or both parents are very tall or very short, or when the two parental heights differ substantially.

Regression toward the population mean means that children of parents at height extremes are often less extreme than a direct family average might suggest.

RCPCH digital growth charts use a separate method based on parental height z-scores and a regression factor. That method is not the same as the simple 13 cm formula.

This site does not calculate the RCPCH mid-parental centile, parental z-scores, regression correction, or a competing result.

The calculator’s broad positive input maximum is a technical protection against likely entry or unit errors. It is not a statement that every accepted value is biologically typical.

Use the Mid-Parental Height Calculator to calculate the simple family-height center and approximate range from both biological parents’ measured adult heights.

Read What Is Mid-Parental Height? when the question is what the estimate and range mean and what the method does not include.

Use the Height Percentile Calculator to compare the child’s current standing height with the CDC age- and sex-specific reference.

Read What Does a Child’s Height Percentile Mean? for an explanation of current percentile position, repeated measurements, and interpretation boundaries.

Use the Child Growth Velocity Calculator to calculate recorded height change between two dates.

Read What Is Growth Velocity in Children? to understand why a growth rate is different from a percentile or family-height estimate.

Read How to Read a CDC Growth Chart for chart axes, percentile curves, plotting, and repeated-measurement context.

Use the Child Growth Chart Calculator to review current CDC height and weight reference positions. It does not predict adult height.

A calculator cannot decide whether a child’s height, growth rate, puberty pattern, or family-height difference requires medical evaluation. Consider discussing growth with a healthcare professional when:

• accurate serial height measurements show decreasing growth velocity or downward crossing of height percentiles after early childhood;
• the child’s current height is well below the age- and sex-specific reference or substantially different from the expected family-height context;
• puberty appears unusually early, delayed, stalled, or different from the child’s broader growth pattern;
• abnormal body proportions, chronic illness, significant symptoms, medication exposure, nutritional concerns, or a known genetic or skeletal condition are present;
• you are uncertain about parental-height measurements, the selected historical formula, bone age, adult-height prediction, or whether a specialist assessment is appropriate.

Bring accurate dated height measurements, the growth chart, both biological parents’ measured adult heights when available, earlier medical records, puberty history, medication history, and any prior bone-age or laboratory reports.

Do not use one mid-parental height result alone to diagnose short or tall stature, order testing, request imaging, start supplements or hormones, change treatment, or decide that professional follow-up is unnecessary. Read the Medical Disclaimer.