How accurate is the mid-parental height method?

The mid-parental formula is accurate to about ±2 inches for most children. Genetics account for roughly 80% of adult height, with the remaining 20% influenced by nutrition, sleep, and health during childhood.

What is the mid-parental height formula?

For boys: (mother's height + father's height) / 2 + 2.5 inches. For girls: (mother's height + father's height) / 2 − 2.5 inches. The ±2 inch range captures ~95% of children.

At what age do children stop growing?

Girls typically stop growing around age 14-16, about 2 years after their first period. Boys usually stop growing around age 16-18 after voice changes and other puberty milestones.

Does nutrition affect final height?

Yes. Adequate protein, calcium, vitamin D, and zinc are critical during childhood and adolescence. Chronic malnutrition can reduce final height by several inches below genetic potential.

Can you predict adult height from a child's current height?

Yes, approximately. A child at the 50th percentile at age 5 tends to stay near the 50th percentile into adulthood. Growth charts and bone age X-rays can refine predictions further.

Height Calculator

Predict a child's adult height using the mid-parental method. Enter parents' heights to estimate how tall your child will be.

Mother's Height (feet)

Mother's Height (inches)

Father's Height (feet)

Father's Height (inches)

Child's Sex

Predicted Adult Height

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Height in Centimeters —

Range Low (−2 in) —

Range High (+2 in) —

Extended More scenarios, charts & detailed breakdown ▾

Mother's Height (feet)

Mother's Height (inches)

Father's Height (feet)

Father's Height (inches)

Child's Sex

Predicted Height

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In Centimeters —

Low Estimate —

High Estimate —

Professional Full parameters & maximum detail ▾

Child's Current Height

Child's Current Weight

lbs

Child's Age

years

Mother's Height (feet)

Mother's Height (inches)

Father's Height (feet)

Father's Height (inches)

Child's Sex

Predicted Adult Height

Mid-Parental Method —

Khamis-Roche Estimate —

Predicted Height (cm) —

Range Low (−2 in) —

Range High (+2 in) —

Child's Current Stats

Child's Current BMI —

BMI Category (age-adjusted) —

Current Height in cm —

Current Height in meters —

How to Use This Calculator

Enter both parents' heights in feet and inches.
Select the child's sex.
The calculator instantly shows the predicted adult height using the mid-parental method, plus a ±2 inch range.

Formula

Boys: (Mom + Dad) / 2 + 2.5 inches
Girls: (Mom + Dad) / 2 − 2.5 inches

Range: Predicted ± 2 inches (covers ~95% of outcomes)

Example

Example: Mom is 5'4" (64"), Dad is 5'10" (70"). For a boy: (64+70)/2 + 2.5 = 69.5" = 5'9.5". Range: 5'7.5" to 5'11.5".

Frequently Asked Questions

The mid-parental formula is accurate to about ±2 inches for most children. Genetics account for roughly 80% of adult height, with the remaining 20% influenced by nutrition, sleep, and health during childhood.
For boys: (mother's height + father's height) / 2 + 2.5 inches. For girls: (mother's height + father's height) / 2 − 2.5 inches. The ±2 inch range captures ~95% of children.
Girls typically stop growing around age 14-16, about 2 years after their first period. Boys usually stop growing around age 16-18 after voice changes and other puberty milestones.
Yes. Adequate protein, calcium, vitamin D, and zinc are critical during childhood and adolescence. Chronic malnutrition can reduce final height by several inches below genetic potential.
Yes, approximately. A child at the 50th percentile at age 5 tends to stay near the 50th percentile into adulthood. Growth charts and bone age X-rays can refine predictions further.

Related Calculators

Sources & References (5) ▾

Tanner JM & Whitehouse RH — Clinical longitudinal standards for height, weight, height velocity, weight velocity, and stages of puberty. Arch Dis Child. 1976;51(3):170-179 — Archives of Disease in Childhood
Luo ZC et al. — Target height as predicted by parental heights in a population-based study. Pediatr Res. 1998;44(4):563-571 — Pediatric Research
Silventoinen K — Determinants of variation in adult body height. J Biosoc Sci. 2003;35(2):263-285 — Journal of Biosocial Science
WHO — Growth reference data for 5-19 years — World Health Organization
CDC — Child & Teen BMI Calculator Background: Growth Charts — CDC