Baby Height Calculator — Free Adult Height Predictor
Predict your child's estimated adult height based on both parents' heights using the mid-parental height method. See the predicted height with a likely range for boys or girls.
Predicted Adult Height
Predicted Height (Boy)
5'10.0"
Predicted Range
Summary: Using the mid-parental height method, a boy with a mother of 5'5.0" and father of 5'10.0" is predicted to reach an adult height of approximately 5'10.0", with a likely range of 5'7.0" to 6'1.0". Genetics account for about 60-80% of height, with nutrition, health, and environment influencing the remainder.
How to Use the Baby Height Calculator
- Select your unit system: Choose between Imperial (feet and inches) or Metric (centimeters). The calculator adjusts all input fields and results to your chosen system.
- Select the child's sex: Choose Boy or Girl. The prediction formula differs between sexes because males are typically about 5 inches (13 cm) taller than females on average. Selecting the correct sex is essential for an accurate prediction.
- Enter both parents' heights: Enter the mother's height and father's height. In Imperial mode, use separate feet and inches fields. In Metric mode, enter height in centimeters. Use the biological parents' heights for the most accurate prediction, as the formula is based on genetic inheritance.
- Review the predicted adult height: The results show the predicted adult height for your child, a range of likely heights (plus or minus 3.35 inches / 8.5 cm), both parents' heights for reference, and the mid-parental height used in the calculation.
This prediction estimates the most likely adult height but individual results can vary. Genetics account for 60% to 80% of height, with nutrition, health, sleep, and activity levels influencing the remaining portion. Use this as a general guide rather than a definitive answer. For specific growth concerns, consult your child's pediatrician.
Mid-Parental Height Formula
For Boys:
Predicted Height = (Mother's Height + Father's Height + 13 cm) / 2 For Girls:
Predicted Height = (Mother's Height + Father's Height - 13 cm) / 2 Prediction Range:
Range = Predicted Height +/- 8.5 cm (3.35 inches) Variables Explained
- 13 cm (5.12 inches): This is the average height difference between adult males and females. For boys, it is added to account for the taller average male height. For girls, it is subtracted. This correction normalizes the parental heights to the same sex before averaging.
- Division by 2: Averaging the sex-adjusted parental heights gives the mid-parental height, which represents the genetic target height for the child. This assumes roughly equal genetic contribution from each parent.
- +/- 8.5 cm (3.35 inches): This range accounts for the natural genetic variation among siblings and the influence of non-genetic factors. About 68% of children will fall within this range (one standard deviation). About 95% will fall within twice this range (+/- 17 cm).
Step-by-Step Example
Predict the adult height for a boy with a mother of 5'4" (162.5 cm) and father of 5'11" (180.3 cm):
- Mother's height: 162.5 cm
- Father's height: 180.3 cm
- Add sex correction: 162.5 + 180.3 + 13 = 355.8
- Divide by 2: 355.8 / 2 = 177.9 cm (5'10.0")
- Range low: 177.9 - 8.5 = 169.4 cm (5'6.7")
- Range high: 177.9 + 8.5 = 186.4 cm (6'1.3")
The boy is predicted to reach an adult height of about 5'10", with a likely range from 5'6.7" to 6'1.3". The prediction would change to about 5'4.9" (164.9 cm) for a girl, with a range of 5'1.6" to 5'8.2".
Practical Examples
Example 1: Average-Height Parents
Kevin and Laura want to predict their son's adult height. Kevin is 5'10" (178 cm) and Laura is 5'5" (165 cm).
- Boy prediction: (165 + 178 + 13) / 2 = 178 cm (5'10.1")
- Range: 169.5 cm to 186.5 cm (5'6.7" to 6'1.4")
- Girl prediction: (165 + 178 - 13) / 2 = 165 cm (5'5.0")
With both parents near the population average, their son is predicted to reach approximately 5'10" — very close to his father's height. The range of 5'6.7" to 6'1.4" covers the most likely outcomes. If they had a daughter instead, the prediction of 5'5" would be very close to Laura's height, reflecting how the formula tends to predict heights near the same-sex parent's height when the parents are close to average.
Example 2: Significant Height Difference Between Parents
David is 6'3" (190.5 cm) and Maria is 5'1" (155 cm). They have a daughter and want to predict her adult height.
- Girl prediction: (155 + 190.5 - 13) / 2 = 166.3 cm (5'5.5")
- Range: 157.8 cm to 174.8 cm (5'2.1" to 5'8.8")
- Boy prediction: (155 + 190.5 + 13) / 2 = 179.3 cm (5'10.6")
The large height difference between the parents (14 inches) creates a wider effective range of outcomes. Their daughter is predicted at 5'5.5", which falls between both parents. She could range from close to her mother's height (5'2") to noticeably taller (5'9"). In cases of extreme parental height differences, the prediction's accuracy is somewhat reduced because the formula assumes height genes blend evenly, which does not always happen in practice.
Example 3: Taller-Than-Average Parents
Brian (6'2", 188 cm) and Patricia (5'9", 175 cm) are both above average height and want to predict their son's and daughter's heights.
- Boy: (175 + 188 + 13) / 2 = 188 cm (6'2.0")
- Boy range: 179.5 cm to 196.5 cm (5'10.7" to 6'5.4")
- Girl: (175 + 188 - 13) / 2 = 175 cm (5'8.9")
- Girl range: 166.5 cm to 183.5 cm (5'5.6" to 6'0.2")
With both parents well above average, their children are predicted to be tall as well. Their son is predicted at 6'2" — matching his father's height — with a potential range up to 6'5.4". Their daughter is predicted at nearly 5'9", matching her mother. However, a statistical phenomenon called regression to the mean suggests that children of very tall parents are, on average, somewhat shorter than the prediction, while children of very short parents tend to be somewhat taller. The formula does not account for this, which can cause slight overestimation for very tall parents and underestimation for very short ones.
Average Adult Heights by Region
| Region | Male Average | Female Average | Difference |
|---|---|---|---|
| Netherlands | 5'11.9" (182.5 cm) | 5'6.7" (169.3 cm) | 5.2" (13.2 cm) |
| United States | 5'9.5" (176.9 cm) | 5'4.0" (163.3 cm) | 5.4" (13.6 cm) |
| United Kingdom | 5'10.1" (178.2 cm) | 5'4.7" (164.4 cm) | 5.4" (13.8 cm) |
| China | 5'7.7" (171.8 cm) | 5'2.6" (159.2 cm) | 5.0" (12.6 cm) |
| India | 5'5.4" (166.5 cm) | 5'0.4" (153.7 cm) | 5.0" (12.8 cm) |
| Global Average | 5'7.5" (171.0 cm) | 5'3.0" (159.5 cm) | 4.5" (11.5 cm) |
Tips and Complete Guide to Child Height Prediction
Understanding the Role of Genetics
Height is one of the most heritable human traits, with genetics explaining 60% to 80% of the variation in adult height within well-nourished populations. However, height is influenced by hundreds of genes, not just one or two, which is why siblings can differ significantly in height despite sharing the same parents. Each parent contributes roughly half of the height-related genes, but the specific combination inherited is random. This genetic lottery explains the prediction range — children can end up anywhere within the spectrum defined by their parents' combined genetic potential.
Supporting Your Child's Growth Potential
While you cannot change the genetic component, you can optimize the environmental factors that influence height. Ensure adequate nutrition with emphasis on protein, calcium, vitamin D, and zinc — all critical for bone growth. Encourage regular physical activity, which stimulates growth hormone release and bone development. Prioritize sufficient sleep (growth hormone is primarily released during deep sleep). Address any chronic health conditions early, as untreated conditions like celiac disease, growth hormone deficiency, or thyroid disorders can impair growth. Regular well-child checkups with growth monitoring help catch any growth issues early.
Limitations of Height Prediction
The mid-parental height method has several known limitations. It assumes that both parents contribute equally to height genes, which is a simplification. It does not account for regression to the mean (very tall or very short parents tend to have children closer to the average). It cannot predict the effects of health conditions, nutritional deficiencies, or hormonal factors during childhood. It uses biological parents' heights, so adopted children or children conceived with donor gametes need the biological parents' heights for accurate prediction. For more precise predictions, pediatric endocrinologists use bone age X-rays combined with growth data.
Growth Charts and Percentiles
Growth charts from the WHO and CDC track a child's height relative to other children of the same age and sex. A child at the 50th percentile is average height, while the 75th percentile means they are taller than 75% of peers. Our baby weight calculator uses similar percentile tracking for weight. What matters most is not the specific percentile but whether the child follows a consistent growth pattern over time. Crossing percentile lines (moving significantly up or down) may warrant investigation, even if the child remains within the normal range.
Common Mistakes to Avoid
- Treating the prediction as certain: The prediction is a statistical estimate with a meaningful range of uncertainty. Children can end up significantly taller or shorter than the predicted value.
- Using non-biological parents' heights: The formula relies on genetic inheritance. Step-parents', adoptive parents', or donor heights do not predict the child's genetic potential.
- Comparing your child's current height to the prediction: Children grow at different rates at different ages. A child who is short at age 5 may catch up during puberty, and vice versa. The prediction applies to final adult height, not height at any specific age.
- Worrying about small deviations from growth charts: Growth is not perfectly smooth. Minor fluctuations in percentile ranking are normal. Focus on the overall trend over months and years, not individual measurements.
- Ignoring signs of growth disorders: If your child's growth rate is significantly below average or the prediction differs drastically from growth chart projections, discuss this with your pediatrician for appropriate evaluation.
Frequently Asked Questions
The mid-parental height method is the most widely used formula for predicting a child's adult height from parental heights. For boys, the formula averages both parents' heights and adds 2.5 inches (6.5 cm) to account for the typical height difference between males and females: (Mother's Height + Father's Height + 13 cm) / 2. For girls, the formula averages both parents' heights and subtracts 2.5 inches (6.5 cm): (Mother's Height + Father's Height - 13 cm) / 2. The result represents the most likely adult height, with a range of plus or minus 3.35 inches (8.5 cm) to account for genetic variation and environmental factors. This method correctly predicts height within this range about 68% of the time.
The mid-parental height prediction is a reasonable estimate but has meaningful uncertainty. The prediction range of plus or minus 3.35 inches (8.5 cm) means the actual adult height could differ by several inches from the calculated value. Genetics account for about 60% to 80% of height determination, but nutrition, health during childhood, hormonal factors, sleep quality, and physical activity also play significant roles. The prediction is most accurate when both parents are of average height and the child has no health conditions affecting growth. Children who are unusually tall or short relative to the prediction may need evaluation for growth disorders, nutritional deficiencies, or hormonal imbalances.
Girls typically reach their adult height by age 14 to 16, about 2 to 3 years after the onset of menstruation. Boys typically continue growing until age 16 to 18, though some may grow until their early twenties. The growth plates (epiphyseal plates) in the long bones gradually fuse as puberty progresses, eventually stopping longitudinal growth entirely. Growth velocity peaks during puberty — girls experience their growth spurt around ages 10 to 14, gaining about 3.5 inches per year at peak, while boys experience theirs around ages 12 to 16, gaining about 4 inches per year at peak. A child's current height percentile on growth charts often provides a rough preview of adult height.
Yes, nutrition significantly influences whether a child reaches their genetic height potential. Chronic malnutrition or specific nutrient deficiencies during childhood and adolescence can prevent a child from reaching their genetically determined height. Key nutrients for growth include protein (essential for building new tissue), calcium and vitamin D (for bone growth and density), zinc (involved in cell division and growth), and iron (for oxygen transport and energy metabolism). The first 1,000 days of life (conception through age 2) are particularly critical, as nutritional deficits during this period can have lasting effects on growth. In well-nourished populations, genetics play a larger role in height determination than nutrition.
Birth length has only a weak correlation with adult height. A baby born longer than average may or may not end up taller than average as an adult. Growth patterns often change significantly during the first 2 years of life, during which many children shift from their birth percentile to their genetically determined growth channel. By age 2, a child's position on the growth chart becomes a somewhat better predictor of adult height, though substantial growth still occurs. The mid-parental height method using parental heights remains the simplest and most commonly used prediction tool. For more precise predictions, a pediatric endocrinologist can use bone age X-rays along with growth data.
Sleep plays a critical role in growth because most growth hormone (GH) is released during deep sleep. Growth hormone secretion peaks during the first few hours of sleep and during slow-wave (deep) sleep stages. Children who consistently get insufficient sleep may have reduced GH secretion, potentially affecting growth. The National Sleep Foundation recommends 10 to 13 hours of sleep for preschoolers, 9 to 11 hours for school-age children, and 8 to 10 hours for teenagers. Beyond growth hormone release, adequate sleep supports overall health, immune function, and cognitive development, all of which contribute to healthy growth. Establishing consistent sleep routines is one practical step parents can take to support their child's growth potential.
Consult a pediatrician if your child's height falls below the 3rd percentile or above the 97th percentile on growth charts, if there is a significant deviation from the expected growth pattern (crossing two or more percentile lines), if growth velocity is unusually slow (less than 2 inches per year after age 3 and before puberty), if puberty signs appear very early (before age 8 in girls, age 9 in boys) or very late (no signs by age 13 in girls, age 14 in boys), or if the predicted adult height based on growth data is significantly different from the mid-parental prediction. A pediatric endocrinologist can perform bone age X-rays and hormone tests to evaluate growth concerns.
Height is a polygenic trait, meaning it is influenced by many genes rather than a single gene. Researchers have identified over 700 genetic variants associated with height, each contributing a small amount to the final result. Parental heights provide the strongest single predictor because they represent the combined effect of all these genetic variants. However, the randomness of genetic inheritance means siblings from the same parents can differ significantly in height. Environmental factors (nutrition, health, physical activity) can modify the genetic potential by several inches in either direction. In developed countries with good nutrition and healthcare, the heritability of height is estimated at 60% to 80%, meaning most of the variation in height among individuals is explained by genetics.
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Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional for medical guidance.
Last updated: February 23, 2026
Sources
- World Health Organization — Child Growth Standards: who.int/tools/child-growth-standards
- Centers for Disease Control and Prevention — Growth Charts: cdc.gov/growthcharts
- ACOG — How Your Fetus Grows During Pregnancy: acog.org/womens-health/faqs