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Use the mid‑parental height formula and your child’s current height to estimate an adult height range.
Parents often wonder "How tall will my child be?" This calculator uses the scientifically-backed mid-parental height method to estimate your child's potential adult height based on genetic factors—specifically, the heights of both parents.
While no prediction method is perfectly accurate, the mid-parental height formula is widely used by pediatricians and endocrinologists as a reasonable estimate of a child's genetic height potential.
For boys: (Mother's height + 13 cm + Father's height) ÷ 2
For girls: (Father's height − 13 cm + Mother's height) ÷ 2
The 13 cm (about 5 inches) adjustment accounts for the average height difference between males and females.
The mid-parental height method provides a target height around which most children will fall. Research shows:
While genetics (parental height) accounts for about 60-80% of height variation, several other factors play important roles:
Adequate nutrition, especially protein, calcium, vitamin D, and zinc, is essential for reaching genetic height potential. Malnutrition or poor diet during childhood can result in shorter stature, while good nutrition allows children to reach their full potential.
Certain chronic conditions can affect growth:
Children who enter puberty earlier tend to have an earlier growth spurt but may end up slightly shorter as adults. Late bloomers often catch up and may reach taller final heights. This is why a child's current percentile doesn't always predict adult percentile.
Growth hormone is primarily released during deep sleep. Children who consistently get adequate sleep (10-13 hours for young children, 9-11 for school-age) are more likely to reach their height potential.
Regular physical activity promotes healthy bone development and growth. Weight-bearing exercise is particularly beneficial for bone health.
Pediatricians track children's growth using percentile charts. Here's what they mean:
What matters most isn't a single percentile measurement but whether your child follows a consistent growth curve over time. A child who has always been at the 25th percentile and continues tracking there is likely growing normally.
See your child's doctor if you notice:
The accuracy and relevance of height predictions varies by age:
Birth length and early growth are influenced by prenatal factors as much as genetics. Many babies "catch up" or "catch down" to their genetic percentile during the first 2 years. Mid-parental predictions are less reliable at this age.
Children typically settle into their genetic growth channel. Mid-parental height becomes more useful. The "double the height at age 2" rule of thumb (for boys; 2 years + a few months for girls) provides a rough estimate.
Growth is steady. Bone age X-rays can provide more precise predictions at this stage if there are concerns.
The pubertal growth spurt accounts for about 20% of final adult height. Girls typically gain 2-3 inches after their first period; boys continue growing for several years after puberty begins.
Doctors may use additional methods for more precise predictions:
An X-ray of the left hand and wrist compared to standard references can determine skeletal maturity. Combined with current height, this allows more accurate prediction than mid-parental height alone.
Tracking height over time on CDC or WHO growth charts shows patterns and helps predict the trajectory toward adult height.
This method uses the child's current height, weight, mid-parental height, and age to provide a more individualized prediction than mid-parental height alone.
No. This calculator provides an approximate range based on parental heights only. If you're concerned about your child's growth—whether too slow, too fast, or unusual in any way—always consult your child's pediatrician, who can evaluate growth patterns over time and order tests if needed.
This calculator shows the standard mid-parental prediction, which is based only on parents' heights. Your child's current height helps you see how they're tracking compared to their genetic potential. Pediatricians use growth charts over time to see whether a child is following an expected curve.
Children naturally vary around the predicted average. The ±8.5 cm range reflects normal variation. Factors like nutrition, health, sleep, and puberty timing also affect final height. If the difference is significant, discuss with your pediatrician.
Mid-parental height predictions become more reliable after age 2, when children have settled into their genetic growth pattern. Predictions improve further as children approach puberty. Bone age X-rays can provide more accurate predictions at any age if needed.
Adequate nutrition (especially protein, calcium, and vitamin D) is essential for reaching genetic height potential, but extra supplements won't make a child grow beyond their genetic programming. However, poor nutrition can prevent a child from reaching their potential height.
Often, yes. Children who enter puberty later have more time to grow before their growth plates close. However, this isn't guaranteed, and "late blooming" should still be evaluated by a pediatrician to rule out underlying conditions.
The rule of thumb that boys will be twice their height at age 2 (and girls at about 18 months) is a rough estimate that works reasonably well for average-height children. It's less accurate for children at extreme percentiles or those with unusual growth patterns.
Short stature alone isn't necessarily a concern—it may simply reflect genetics if parents are shorter. However, if your child is falling off their growth curve, is well below the 3rd percentile, or has other symptoms, a pediatric evaluation is warranted to rule out treatable conditions.