Last updated: June 2026
By CalcOrigin Editorial Team
About Height Calculator
The height calculator is a free online tool that predicts a child's adult height using scientifically validated methods. Whether you are a curious parent wondering how tall your child will be or a healthcare professional tracking growth patterns, this calculator provides reliable estimates based on the Khamis-Roche method and the mid-parent height method. By combining the child's current measurements — age, gender, height, and weight — with parental heights, the calculator generates a statistically grounded prediction of adult stature.
Height prediction has practical applications beyond simple curiosity. Pediatricians use height projections to identify potential growth disorders early, allowing for timely intervention. Parents can use these predictions to plan for their child's future needs, from sports participation to career considerations. The height calculator on this page also includes a built-in height converter for switching between US customary units and metric units, making it useful for international families and medical professionals who work with both measurement systems.
The science behind height prediction has evolved significantly over the past century. Early methods relied solely on parental heights, but modern approaches incorporate the child's own growth trajectory for improved accuracy. This calculator implements two complementary methods so you can compare results and gain a more complete picture of your child's potential adult height. For a broader assessment of your child's overall growth and development, consider using our BMI calculator to track weight status alongside height predictions.
How to Predict Child's Adult Height
Using this height calculator is straightforward. Enter the child's age, gender, current height, current weight, and both parents' heights. The calculator processes this information using two distinct prediction methods and displays the results instantly. The more accurate the input data, the more reliable the prediction will be, so take care when measuring the child's height and weight.
The calculator offers two methods for predicting adult height:
- Khamis-Roche Method — Uses linear regression analysis incorporating the child's current height, weight, and the average of both parents' heights. This is the primary method and is most accurate for children between ages 4 and 9.
- Mid-Parent Height Method — A simpler calculation that uses only the parents' heights. This method can be used for children of any age, including unborn infants, but has a wider margin of error.
For the most reliable results, measure the child's height without shoes, using a flat surface and a right-angle tool. Weight should be measured in light clothing using a properly calibrated scale. Parental heights should be self-reported or measured heights rather than estimates. If you are interested in tracking other physical development metrics, our ideal weight calculator can help determine healthy weight ranges based on height and age.
The calculator automatically switches between US units (feet, inches, pounds) and metric units (centimeters, kilograms) based on your selection. This flexibility makes it suitable for users worldwide, whether you follow the imperial system commonly used in the United States or the metric system used in most other countries. The results display in both formats for convenience, showing predicted height in feet and inches as well as centimeters.
The Khamis-Roche Method Explained
The Khamis-Roche method, developed by Dr. Harry Khamis and Dr. Alex Roche, is widely regarded as one of the most accurate height prediction methods that does not require bone age X-rays. Published in 1994, this method uses multiple linear regression to predict adult height based on three key variables: the child's current height, the child's current weight, and the mid-parent height (the average of both parents' heights).
Formula:
Predicted Height = β₀ + β₁×(child height) + β₂×(child weight) + β₃×(mid-parent height)
The coefficients β₀, β₁, β₂, and β₃ vary based on the child's age and gender. The method was developed using data from the Fels Longitudinal Study, which tracked the growth of thousands of children over several decades. For most children, the Khamis-Roche method predicts adult height within approximately 1.5 inches (3.8 cm) for 90% of cases, making it a reliable tool for clinical and personal use.
It is important to note that the Khamis-Roche method is most accurate for Caucasian children between the ages of 4 and 9 who are growing normally without any growth-related medical conditions. The accuracy decreases for children outside this age range, particularly during puberty when growth rates become more variable due to hormonal changes. For adolescents who have already begun puberty, bone age assessment methods like the Greulich-Pyle atlas may provide more accurate predictions.
Mid-Parent Height Method
The mid-parent height method, also known as the Tanner method, is a simpler approach that estimates a child's adult height using only the heights of both biological parents. This method has been used by pediatricians for decades as a quick screening tool and can be applied to children of any age, including unborn infants where the Khamis-Roche method is not applicable.
Formula:
For Boys: (Father's Height + Mother's Height + 5 inches) ÷ 2
For Girls: (Father's Height + Mother's Height - 5 inches) ÷ 2
The 5-inch adjustment reflects the average height difference between adult men and women in the general population. For example, if the father is 5 feet 10 inches (70 inches) and the mother is 5 feet 5 inches (65 inches), the mid-parent height is 67.5 inches. For a boy, the predicted height would be (70 + 65 + 5) ÷ 2 = 70 inches, or 5 feet 10 inches. For a girl, it would be (70 + 65 - 5) ÷ 2 = 65 inches, or 5 feet 5 inches.
The mid-parent method has an average error of approximately 3.5 inches (9 cm), which is wider than the Khamis-Roche method. However, its simplicity and the fact that it requires no measurements from the child make it valuable for early prediction. This method assumes the child will grow in an environment that supports their genetic potential. For a more comprehensive assessment of your child's overall health, pair this with our calorie calculator to ensure they are getting adequate nutrition for growth.
Height Conversion Guide
The height calculator includes a built-in converter for switching between US customary units (feet and inches) and metric units (centimeters). This is particularly useful for international families, travelers, and healthcare professionals who need to work with both measurement systems. Understanding how to convert between these units is a practical skill for everyday life, from filling out medical forms to shopping for clothing online.
Conversion Formulas:
- Feet and Inches to Centimeters: Convert feet to inches (feet × 12), add the remaining inches, then multiply by 2.54. Example: 5 feet 9 inches = (5 × 12 + 9) × 2.54 = 69 × 2.54 = 175.26 cm
- Centimeters to Feet and Inches: Divide by 2.54 to get total inches, then divide by 12 to get feet. The remainder is the inches. Example: 175 cm ÷ 2.54 = 68.9 inches = 5 feet 8.9 inches
Common height conversions include 5 feet = 152.4 cm, 5 feet 5 inches = 165.1 cm, 5 feet 10 inches = 177.8 cm, and 6 feet = 182.88 cm. The converter on this page handles the math instantly, but knowing the underlying formulas helps you verify results and understand the relationship between the two systems. If you work with other types of measurements, our unit converter provides conversion tools for length, weight, volume, temperature, and more.
Factors That Affect Adult Height
Adult height is determined by a complex interplay of genetic and environmental factors. Understanding these factors can help parents support their children's growth and development more effectively. While the height calculator provides a statistical prediction based on current data, the actual outcome depends on many variables that influence the growth process from conception through adolescence.
Genetic Factors (60-80%): Height is highly heritable, meaning it runs in families. Genome-wide association studies have identified hundreds of genetic variants that influence height, each contributing a small effect. The combination of these variants determines each person's genetic height potential. This is why parental heights are such strong predictors in both the Khamis-Roche and mid-parent methods used by this calculator.
Nutritional Factors: Adequate nutrition during childhood and adolescence is essential for reaching genetic height potential. Protein provides the building blocks for growing tissues, calcium and vitamin D support bone development, zinc is crucial for cell division and growth, and overall caloric intake must be sufficient to fuel the growth process. Malnutrition during critical growth periods can permanently reduce adult height, which is why average heights have increased dramatically in developed countries over the past century as nutrition improved.
Hormonal Factors: Growth hormone, thyroid hormone, and sex hormones (estrogen and testosterone) all play crucial roles in the growth process. Growth hormone stimulates the growth plates in long bones, while sex hormones drive the growth spurt during puberty and eventually signal the growth plates to close, ending further height increase. Growth hormone disorders or thyroid deficiencies can significantly impact final adult height if not treated properly.
Environmental and Lifestyle Factors: Sleep quality, physical activity, stress levels, and overall health all contribute to growth outcomes. Growth hormone is primarily secreted during deep sleep, making adequate rest critical for children. Regular physical activity, particularly weight-bearing exercises, supports bone density and overall musculoskeletal development. Chronic illness, certain medications, and significant psychological stress can also impact growth rates during childhood.
Nutrition for Optimal Growth in Children
Proper nutrition is one of the most controllable factors influencing a child's growth trajectory. While the height calculator can predict potential adult height, ensuring your child receives adequate nutrition gives them the best chance of reaching that potential. A balanced diet rich in specific nutrients supports healthy bone development and overall growth during the critical childhood and adolescent years.
Key Nutrients for Growth:
- Protein — Found in meat, fish, eggs, dairy, beans, and legumes. Protein provides amino acids that are the building blocks for all body tissues, including bones and muscles. Children need 0.5-0.8 grams of protein per pound of body weight daily.
- Calcium — Found in dairy products, leafy greens, fortified foods, and almonds. Calcium is essential for bone mineralization and density. Children ages 4-8 need about 1,000 mg daily, while teens need 1,300 mg.
- Vitamin D — Produced through sun exposure and found in fatty fish, egg yolks, and fortified milk. Vitamin D helps the body absorb calcium and is critical for bone growth. Many children benefit from supplementation, especially in winter months.
- Zinc — Found in meat, shellfish, nuts, seeds, and whole grains. Zinc supports cell division and growth. Zinc deficiency is associated with growth stunting in children worldwide.
- Iron — Found in red meat, poultry, beans, and fortified cereals. Iron supports oxygen transport to growing tissues and is particularly important during adolescent growth spurts.
A well-rounded diet that includes a variety of whole foods from all food groups typically provides adequate nutrition for healthy growth. Processed foods, excessive sugar, and empty calories should be limited as they displace nutrient-dense foods without contributing to growth. If you have concerns about your child's nutritional intake, consult with a pediatrician or registered dietitian. Our BMR calculator can help estimate daily caloric needs based on age, height, weight, and activity level to ensure adequate energy intake for growth.
Understanding Growth Charts and Percentiles
Growth charts are standardized tools used by pediatricians to track a child's physical development over time. They display height, weight, and head circumference percentiles compared to a reference population of children of the same age and gender. The height calculator on this page predicts adult height, but growth charts help monitor whether a child is growing at a healthy rate throughout childhood.
A child at the 50th percentile for height means they are taller than 50% of children their age. Being at a lower percentile does not necessarily indicate a problem — what matters more is that the child follows their own growth curve consistently over time. A sudden drop in percentiles may signal a growth issue that requires medical evaluation, while a consistent growth pattern along any percentile is generally reassuring.
The World Health Organization (WHO) growth standards are used for children under 2 years, while the CDC growth charts are commonly used for children ages 2 and older in the United States. These charts are periodically updated to reflect changes in population health and nutrition. Pediatricians typically measure and plot growth at each well-child visit, allowing them to identify deviations from expected growth patterns early. For tracking weight-related growth, our healthy weight calculator can help determine appropriate weight ranges for your child's height and age.
The Role of Genetics in Determining Height
Genetics play the largest role in determining adult height, accounting for an estimated 60-80% of the variation in height between individuals. Over 700 genetic variants have been associated with height, though most have very small individual effects. The height calculator captures this genetic influence through parental height inputs, since parents and children share about 50% of their genetic material.
The heritability of height means that tall parents tend to have tall children, and short parents tend to have short children. However, this is not absolute — genetic recombination and environmental factors can produce children who are significantly taller or shorter than their parents. This phenomenon, known as regression to the mean, often results in children being closer to the population average height than their parents.
Genetic conditions can also affect height. Disorders such as Turner syndrome, Marfan syndrome, and achondroplasia have significant impacts on adult height. If a child's growth pattern deviates significantly from predictions made by the height calculator, or if there is a family history of genetic conditions affecting growth, consultation with a pediatric endocrinologist or geneticist may be appropriate for further evaluation and guidance.
Common Myths About Height and Growth
There are many misconceptions about height and growth. Using a scientific height calculator helps separate fact from fiction by basing predictions on validated research rather than anecdotal beliefs. Here are some common myths debunked:
- Myth: Drinking milk makes you taller. While milk provides calcium and vitamin D for bone health, no single food can increase height beyond genetic potential. Adequate overall nutrition is what matters, not any specific food.
- Myth: Hanging or stretching exercises increase height. These activities improve posture and spinal alignment, which can make someone appear taller, but they do not increase bone length or actual height.
- Myth: You grow until age 25. Most people stop growing by age 18-20. The growth plates in long bones fuse after puberty, making additional height increase impossible. Some subtle changes in spinal discs can cause minor height changes, but not significant growth.
- Myth: Height is determined solely by the father's side. Both parents contribute equally to a child's genetic height potential. The mid-parent method used in this calculator reflects this by averaging both parents' heights.
- Myth: Growth hormone supplements can make anyone taller. Growth hormone therapy is only effective for children with diagnosed growth hormone deficiency. Using it without medical need can cause serious side effects including joint pain and diabetes.
How to Measure Height Accurately
Accurate height measurement is essential for getting reliable predictions from the height calculator. Even small measurement errors can affect the predicted adult height, especially when using the Khamis-Roche method which incorporates the child's current height directly into the regression formula. Follow these guidelines for accurate measurement at home:
- Remove shoes and heavy clothing — footwear adds variable amounts to height, and heavy clothing can make it difficult to stand straight. Measure in lightweight clothing or underwear.
- Stand against a flat wall — position the child with heels together, back straight, and shoulders against the wall. The wall should be free of baseboards or molding that could affect positioning.
- Look straight ahead — the head should be in the Frankfort horizontal plane, where the lower edge of the eye socket is level with the upper edge of the ear canal. This ensures consistent head positioning.
- Use a flat object for marking — place a ruler, book, or carpenter's square on top of the head at a right angle to the wall. Mark the wall at the bottom edge of the object.
- Measure from floor to mark — use a tape measure to measure the distance from the floor to the pencil mark. For best accuracy, take two measurements and average them.
For infants and toddlers who cannot stand independently, recumbent length is measured lying down using a length board or infantometer. This measurement is typically about 0.5-1 cm longer than standing height due to the effects of gravity on the spine throughout the day. If measuring parents for the mid-parent method, try to use measured heights rather than self-reported estimates, as people tend to overestimate their height by an average of 0.5-1 inch.
When Do Children Stop Growing?
Understanding the typical timeline of human growth helps set realistic expectations for the predictions made by the height calculator. Growth follows a predictable pattern from birth through adolescence, with two major growth spurts and a gradual decline in growth rate as adulthood approaches.
Infancy to Age 2: This is the fastest growth period of life. Infants typically grow about 10 inches (25 cm) in their first year and about 5 inches (13 cm) in their second year. By age 2, most children have reached about half their adult height.
Childhood (Ages 3-10): Growth slows to a steady rate of about 2-2.5 inches (5-6 cm) per year. During this period, growth is primarily driven by growth hormone and thyroid hormone. This is the ideal age range for the Khamis-Roche method used in this calculator, as growth patterns are relatively stable and predictable.
Puberty (Ages 8-14 for girls, 10-16 for boys): The adolescent growth spurt is driven by sex hormones. Girls typically begin their growth spurt around age 10-11 and peak at about age 12, growing 3-4 inches per year at the peak. Boys start later, around age 12-13, and peak at about age 14, growing 4-5 inches per year at the peak. Boys tend to grow more during puberty because they have two additional years of pre-pubertal growth and a more intense growth spurt.
Growth Plate Fusion: After the pubertal growth spurt, sex hormones signal the growth plates (epiphyseal plates) in the long bones to fuse, ending further height increase. Girls' growth plates typically fuse around age 14-15, while boys' fuse around age 16-18. After fusion, no amount of nutrition, exercise, or supplements can increase height. For tracking other aspects of physical development, our body fat calculator can help monitor healthy body composition changes during growth.
7 Tips for Supporting Healthy Growth in Children
While the height calculator predicts potential adult height based on current data, these practical tips can help your child reach their full growth potential by creating optimal conditions for healthy development:
- Ensure adequate sleep — growth hormone is primarily released during deep sleep stages. Children ages 4-12 need 9-12 hours per night, while teenagers need 8-10 hours. Establish consistent bedtime routines and limit screen time before bed.
- Provide balanced, nutrient-dense meals — focus on whole foods rich in protein, calcium, vitamin D, zinc, and iron. Limit processed foods, sugary drinks, and empty calories that displace nutritious options.
- Encourage regular physical activity — weight-bearing exercises like running, jumping, and sports support bone density and overall health. Aim for at least 60 minutes of moderate-to-vigorous physical activity daily.
- Maintain regular health checkups — annual pediatric visits allow tracking of growth percentiles and early detection of potential issues. Bring growth records and any concerns to each visit.
- Manage stress effectively — chronic stress can elevate cortisol levels, which may suppress growth hormone production. Support your child with adequate downtime, relaxation, and emotional support.
- Avoid tobacco and alcohol exposure — exposure to cigarette smoke and alcohol during childhood can negatively impact growth and development. Maintain a smoke-free home environment.
- Stay hydrated — proper hydration supports all bodily functions, including growth. Encourage water as the primary beverage and limit sugary drinks that can interfere with nutrient absorption.
Final Thoughts
The height calculator provides a science-based prediction of your child's adult height using two complementary methods. While these predictions are statistically grounded, remember that they are estimates, not guarantees. Every child grows at their own pace, and the actual adult height can vary from predictions due to the complex interplay of genetics, nutrition, hormones, and environmental factors discussed throughout this guide.
Use this calculator as a tool for understanding your child's growth potential and as a starting point for conversations with healthcare providers if you have concerns about growth patterns. The Khamis-Roche method offers good accuracy for most children, while the mid-parent method provides a quick reference that can be used from birth onward. Regular monitoring of your child's growth using growth charts provides the most complete picture of their development trajectory over time.
This height calculator is completely free to use, requires no registration, and works on all devices. Bookmark this page to return as your child grows and you want to update predictions with new measurement data. For a more complete picture of your child's health and development, explore our related calculators including the BMI calculator, calorie calculator, and body fat calculator.
To learn more about height calculator, visit NIH.
Frequently Asked Questions
How accurate is the Khamis-Roche method?
The Khamis-Roche method predicts adult height within about 1.5 inches (3.8 cm) for 90% of children. It is most accurate for Caucasian children between ages 4 and 9 who are free from growth-related conditions. Accuracy decreases during puberty when growth rates become more variable.
What age is best for height prediction?
The Khamis-Roche method works best for children between ages 4 and 9. After age 10, puberty timing becomes a significant factor that can affect predictions. Girls typically stop growing around age 14-15, and boys around age 16-18.
Can I predict my unborn child's height?
Yes, use the mid-parent height method which only requires the parents' heights. The formula calculates (Father's height + Mother's height ± 5 inches) / 2 depending on gender. The second calculator on this page is designed specifically for this purpose.
What factors affect adult height?
Height is determined by genetics (60-80%) and environmental factors including nutrition, sleep, physical activity, and overall health during childhood. Key nutrients include protein, calcium, vitamin D, and zinc for optimal growth.
How do I convert height from feet and inches to centimeters?
Multiply total inches by 2.54 to get centimeters. For example, 5 feet 9 inches equals 69 inches, and 69 × 2.54 = 175.26 cm. The height converter on this page does this calculation automatically for you.
Can nutrition affect my child's adult height?
Yes, proper nutrition during childhood and adolescence is critical for reaching full genetic height potential. Key nutrients include protein, calcium, vitamin D, zinc, and adequate calories. Malnutrition during growth periods can permanently reduce adult height.
Do boys and girls stop growing at different ages?
Yes. Girls typically stop growing around age 14-15, about 2 years after their first period. Boys usually continue growing until age 16-18, with growth slowing significantly after puberty. Boys also tend to have a more intense adolescent growth spurt.
What is the mid-parent height method?
The mid-parent height method predicts adult child height by averaging the parents' heights and adjusting for gender. For boys, add 5 inches to the average; for girls, subtract 5 inches. This method has an average error of about 3.5 inches.
Can exercise help my child grow taller?
Regular exercise supports healthy growth but does not directly increase height beyond genetic potential. Activities like swimming, stretching, and sports promote good posture, bone health, and overall development. Aim for 60 minutes of daily physical activity.
How is height measured accurately at home?
Remove shoes, stand against a flat wall with heels together, look straight ahead, and use a flat object like a book placed on the head to mark the wall. Measure from floor to mark with a tape measure for the most accurate reading.
What is considered tall for a man or woman?
In the US, the average height is about 5 feet 9 inches for men and 5 feet 4 inches for women. Above 6 feet for men and 5 feet 7 inches for women is generally considered tall. Averages vary significantly by country and ethnicity.
Does sleep affect height growth?
Yes, growth hormone is primarily released during deep sleep. Children and teens need 8-10 hours of quality sleep per night for optimal growth. Consistent sleep schedules and limiting screen time before bed support healthy sleep patterns.
