Height Calculator: Predict Adult Height Based on Parents’ Heights

A height calculator is a simple tool used to estimate how tall a child may grow to be as an adult. These predictions are based on established growth formulas that consider parental height and biological sex.

While genetics play a major role in determining final height, other factors like nutrition, sleep, and hormone levels can influence growth over time. Predictive methods help estimate adult stature within a reasonable range, even though exact outcomes can vary.

This article explains how a height calculator works, what affects its accuracy, and which factors influence growth during childhood and adolescence. It also provides a reliable calculator based on widely used prediction formulas.

Online height calculator

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How is estimated height calculated? 

This calculator was created using formulas that determine the target height by using the parents’ height. The child’s sex also plays a role at predicting height.

For girls: The mother’s height (in cm) is added to the father’s height (in cm), being sure to subtract 13 cm from the father’s height first. The sum of these two values is then divided by two. 
For boys: 13 cm are added to the father’s height (in cm), and this sum is then added to the mother’s height. The total of these two combined values is then divided by two.

Noting that there are many factors that can affect the rate at which each child grows, height predictions are communicated as a range, with 5 cm of variation (either 5 cm more or less than the calculated value). 

For example: To calculate the height of a baby girl, you must first know the parents’ heights. If the mother’s height is 160 cm and the father is 173 cm, the calculation would be 160 + (173 - 13)/2 = 160 cm. This means the baby girl’s height is predicted to be between 155 to 165 cm.

In addition to this standard formula, more advanced models like the Khamis-Roche method may include the child’s current height, weight, and age, providing more precise predictions without requiring bone age analysis. These approaches are especially useful in children over 4 years old and have been validated in multiple populations.

Is this result accurate?

This formula is based on an average pattern that represents the majority of cases. However, there are many factors that can affect how a child grows, and it is possible for children to achieve a different height than calculated by adulthood. 

Recent studies show that the accuracy of height calculators depends on the method used. The Khamis-Roche method, for example, has a typical error margin of around 2.1 inches for boys and 1.7 inches for girls. In contrast, traditional methods like Bayley-Pinneau may overestimate or underestimate height in certain cases, especially when bone age differs from chronological age.

No calculator can predict adult height with 100% certainty. Standard errors generally range from 3 to 6 cm, and factors like health, sleep, and nutrition can cause real-life results to vary outside the predicted range.

What can affect the predicted height? 

Most children will grow at the following rhythm:

Although there are many tools to track a child’s growth, several key factors can influence final height, including:

• Nutrition

• Chronic illnesses

• Sleep pattern

• Activity level

Each child’s genetics are another important factor, which target height formulas like this one take into account.

What factors affect my child’s height?

The following biological and environmental components can influence growth and the accuracy of any height calculator:

• Parental height is the most significant predictor of adult height

• Over 12,000 genetic variants are known to affect growth

• Heritability increases with age, peaking during adolescence

• Protein and calcium intake support bone development

• Vitamin D and overall nutrition are essential for reaching growth potential

• Malnutrition in early life can reduce adult height despite genetic advantages

• Sleep promotes growth hormone release during deep sleep

• Sleep deprivation can impair height gain and change body composition

• Physical activity stimulates natural growth hormone production

• Sports and jumping activities help build stronger bones

• Hormones like growth hormone, IGF-1, and thyroid hormone are crucial during growth phases

• Puberty timing strongly influences the pace and total amount of growth

How accurate is a height calculator?

Different height calculators vary in accuracy depending on the method and context:

• Bayley-Pinneau method: About 77% of estimates fall within 10% of final height

• Tanner-Whitehouse method: Precision of approximately 2.6 cm

• Khamis-Roche method: Error margins of 2.1 inches for boys, 1.7 inches for girls

• AI-based models: Mean absolute errors around 4.6 cm

• Standard prediction errors typically range from 3 to 6 cm

Accuracy can also vary depending on:

• Age at time of prediction (older children yield more precise estimates)

• Ethnicity and population-specific factors

• Presence of medical conditions or growth disorders

• Bone age assessment quality and method used

• Environmental conditions such as diet, sleep, and physical activity

Growth patterns throughout childhood

Growth occurs in distinct stages:

• Infancy (0–2 years): Rapid growth, mostly influenced by nutrition

• Childhood (2–10 years): Steady velocity of 5–6 cm per year, with both genes and environment playing strong roles

• Adolescence (10–18 years): Puberty triggers growth spurts, driven by hormonal changes and genetics

While most children follow general patterns, growth tempo and final outcomes vary widely due to individual differences and modifiable lifestyle factors.

Sources used from Literature Review (AMA format):

1. Khamis HJ, Roche AF. Predicting adult stature without using skeletal age: the Khamis-Roche method. Pediatrics. 1994;94(4):504-507.

2. Mlakar M, Gradišek A, Luštrek M, et al. Adult height prediction using the growth curve comparison method. PLoS One. 2023;18(2):e0281960.

3. Ostojic SM. Prediction of adult height by Tanner-Whitehouse method in young Caucasian male athletes. QJM. 2013;106(4):341-345.

4. Barak S, Orhon FS, Demirel F. Comparison of commonly used methods to predict the final height in constitutional tall stature. J Clin Res Pediatr Endocrinol. 2022;14(1):51-67.

5. Hirschhorn J, Lango Allen H, Lindgren CM, et al. Scientists uncover nearly all genetic variants linked to height. Nature. 2024;630(8016):428-434.

6. Scientific American. How much of human height is genetic and how much is due to nutrition? 2024.

7. Butte NF, Puyau MR, Wilson TA, et al. Role of physical activity and sleep duration in growth and body composition of preschool-aged children. Obesity. 2016;24(6):1328-1335.

8. Jurak G, Sorić M, Leskošek B, et al. Factors affecting height velocity in normal prepubertal children. Ann Pediatr Endocrinol Metab. 2018;23(3):126-133.

9. Ranke MB, Lindberg A, Mullis PE, et al. Validation of prediction models for near adult height in children with idiopathic growth hormone deficiency. Horm Res Paediatr. 2016;85(4):253-263.

10. Zandberg M, Wit JM, van Duyvenvoorde HA, et al. Novel method for adult height prediction in children with idiopathic short stature. J Endocr Soc. 2021;5(7):bvac074.

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