Height Calculator – Best Child Height Predictor

Predicts the future adult height of a baby based on parent’s heights and data tables.

Child height predictors

The child height calculator uses a series of formulas and statistical data to predict a child’s adult height based on 6 simple variables (child’s gender, age, height and weight, mother and father’s heights).

A second method that can be used is the gender-specific mid-parental three step method:

■ The first step is to add the parental heights together (whether provided in inches or centimeters).

Mid-parental height = (mother’s height + father’s height) / 2

■ The second step is to add to the value obtained at step 1, either 5 inches (13cm) if the child’s gender is male or subtract 5 inches if the gender of the child is female.

■ The third step is to divide the value obtained at the second step by two, which finds the end results – the child’s future adult predicted height.

Girls Height Formula = (Mid-parental height – 5 inches) / 2

Boys Height Formula = (Mid-parental height + 5 inches) / 2

Whilst height predictors can estimate a future adult height to a degree of accuracy, ultimately the rhythm in which children develop is determined by genetic and environmental factors, general health, nutrition and level of exercise during childhood, factors which cannot be completely accounted for in a model.

1. Genetic determination – child’s adult height linked to that of the mother and father;

2. Nutrition – a child with a nutritiously rich diet during childhood and adolescence will develop harmoniously;

3. Hormone influence – with specific importance of the thyroid and growth hormones;

4. Exercise levels – children who practice sports tend to develop better than their non-exercising peers;

5. Genetic conditions – some syndromes impact on height growth;

6. Corticosteroid medications – can also affect rate of growth.

Impact of genetics on height

It is generally accepted that, from the factors affecting growth, 60 to 80% of the individual’s height is determined by genetics and only the remainder on environmental factors.

A study by Silventoinen et al. on adataset of 8798 Finnish twins found that heritability influence on height was, on average, of 78% in men and 75% in women and that values varied between ethnic populations. Other studies have found that in Asian and African populations, the height heritability is notably lower, at around 65%.

Investigating growth

There are several means to assess  the maturity of a child’s skeletal system and monitor growth. One of the most commonly used is x-ray of left wrist, hand and fingers. The resulting image is compared to standardized images of bone development.

In children, growth is due to the growth plate areas of the bones, which are easy to identify on x-ray because of the different composition (softer and with less minerals) than standard bone. Growth plates look different with age, so the x-ray can also be used to date the child’s age or to compare their development at that age with benchmark values.

Standardized growth charts are also used by pediatricians, for example the WHO charts for infants aged 0 to 2 years and the CDC charts for children above 2. These consist of standard measurements of a child’s height, weight, head size and body mass index.

Growth process also varies by gender and this is exemplified in the growth chart data below, by comparison, with data extracted from the CDC charts.

Age (years)Median female heightMedian male height
43 ft 3 in101 cm3 ft 4 in102 cm
63 ft 9 in115 cm3 ft 9 in115.5 cm
84 ft 2 in127.5 cm4 ft 2 in128 cm
104 ft 7 in138 cm4 ft 6 in138.5 cm
124 ft 11 in151.5 cm4 ft 11 in149 cm
145 ft 4 in160.5 cm5 ft 4 in164 cm
165 ft 4 in162.5 cm5 ft 8 in173.5 cm
185 ft 4 in163 cm5 ft 9 in176 cm
205 ft 5 in163 cm5 ft 9 in177 cm


Harris EF, Weinstein S, Weinstein L, Poole AE. (1980) Predicting adult stature: a comparison of methodologies. Ann Hum Biol.  7(3):225-34.

Wright C., Cheetham T. (1999) “The strengths and limitations of parental heights as a predictor of attained height“, Archives of Disease in Childhood Vol.81(3):257–260.

Tanner JM, Whitehouse RH, Marshall WA, et al. (1975) Assessment of Skeletal Maturity and Prediction of Adult Height (TW2 Method) New York: Academic Press.

Khamis H.J., Roche A.F. (1994) “Predicting adult stature without using skeletal age: the Khamis-Roche method” Pediatrics Vol.4(1):504-7

Silventoinen K et al. Genetic and Environmental Contributions to the Association Between Body Height and Educational Attainment: A Study of Adult Finnish Twins Behavior Genetics volume 30, pages 477–485(2000)


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