# Height Calculator

Created by Małgorzata Koperska, MD and Filip Derma
Reviewed by Bogna Szyk and Jack Bowater
Based on research by
Khamis HJ, Roche AF. Predicting adult stature without using skeletal age: the Khamis-Roche method.; Pediatrics; October 1994See 2 more sources
Wright CM, Cheetham TD. The strengths and limitations of parental heights as a predictor of attained height.; Archives of Disease in Childhood; September 1999Silventoinen K, Kaprio J & Lahelma E. Genetic and Environmental Contributions to the Association Between Body Height and Educational Attainment: A Study of Adult Finnish Twins.; Behavior Genetics volume; November 2000
Last updated: Apr 18, 2024

Table of contents:

This child height calculator answers the question of how tall your children will be. We use two very different methods and describe how to calculate a child's eventual adult height in detail.

If you already have a child over four years old, our future height calculator uses a scientifically proven formula to determine their height.

However, if your kid is younger, you're just curious, or maybe you are pregnant, we have a child height predictor that calculates the child's height based on the parents' height. It's called the Mid-Parental Height Formula.

In the article below, you can learn about a variety of height-related topics, such as when do girls and boys stop growing and what is the average male height. Moreover, we discuss how to get taller (and whether it is possible at all).

## What does a child's height depend on?

How tall will my child be? Will they be as tall as their dad or average height like their grandpa? These questions thrill almost every parent during pregnancy and while the child is continuously growing in the early years. Lots of us believe that children are usually taller than their parents. For sure, that is not a rule, and these trends vary from child to child and from family to family.

The single most significant factor here is genetics. However, environmental aspects still have a lot of impact on the child's height! Let's take a look at a few crucial points:

1. Nutrition – growth requires a lot of energy! Overweight children tend to be taller than others, but staying fit is crucial for their development. You can check your ideal weight using our ideal weight calculator.

2. Hormone levels, especially growth hormone or thyroid hormones.

3. Health conditions, such as coeliac disease or arthritis.

4. Medications such as corticosteroids can affect growth.

5. Genetic conditions: for example, children with Marfan's syndrome tend to grow higher, while children with Down's syndrome are usually shorter than others.

As you can see, one of the most crucial aspects is nutrition. It is so significant that the proper question to consider should be "How much variation (the difference between individuals) in height is attributable to genetic effects and how much to nutritional effects?".

The answer is about 60-80% of the individual's height is determined by genetics. The role of environmental factors (especially nutrition) is estimated to be around 20-40%. These numbers come from estimations of the heritability of human height and from research examining what proportions of the height variation are determined by genetics.

## Height – the genetics behind a human appearance

Based on various scientific studies, heritability contributes to around 80 percent of a child's height. A on almost 9000 twins arrived at results of 78 percent for men and 75 percent for women. As we can see, the heritability varies even for men and women.

These values may vary a lot between ethnic populations as well. This is mainly due to different living environments (including nutrition, lifestyle, and climate conditions) and different genetic combinations across communities. In Asian and African populations, the height heritability is notably lower. Miao-Xin Li of Hunan Normal University in China estimated that in the Chinese population, heritability equals 65 percent. D. F. Roberts found a comparable figure in studies in west Africa.

Heritability allows us to consider how the person's height is determined. Let's analyze it on the following example: a man who is 183 cm (6 ft) tall. The white male population has an average height of 178 cm (5 ft 10 in) with a heritability of 80 percent. Our individual is 5 cm taller than the population average. Analysis of heritability suggests how much of his extra height is a genetic cause and how much is due to environmental factors. In this example, we can say that 4 cm of his extra height is thanks to genetics (80%), and the 1 cm (20%) is an environmental effect (probably a result of good nutrition).

## How tall will I be? – how to calculate a child's height

There are a few methods of predicting the growth of a child. Some use mathematical estimations as a base and are entirely safe (because the child is not exposed to any hazardous factors). The one we provide here (the Khamis-Roche Formula) is proven to be the most accurate without the use of skeletal age. The most straightforward method (Mid-Parental height formula) is based on parents' height only.

The other conventional method of height prediction uses roentgen radiation (which is potentially hazardous – see the medical radiation calculator). It is, however, the most accurate way. The child's "bone age" is determined by using X-ray medical imaging of the child's hand.

## The Khamis-Roche child height predictor

A child's adult height can be predicted using a simple mathematical equation using parent height, current child height, and current child weight. It is valid for children above the age of four.

This method of height prediction is known as the Khamis-Roche Method, and it was developed in 1994 at Wright State University in Dayton, Ohio. The publication by Dr. Harry Khamis and Dr. Alex Roche was called . It's the most accurate method of child height prediction without determining the skeletal age.

For boys, the margin of error is 2.1 inches, and for girls, the margin is 1.7 inches.

Please note that this future child height calculator was developed by research on a group of Caucasian children, so it may be less accurate for kids of other ethnicities.

## The mid-parental child height calculator and formula

The mid-parental formula is the easiest way to calculate a child's height based on the parents' height. Here is how it works:

1. Let's calculate the mid-parental height:

(mother's height + father's height)/2

2. For a girl's future height, subtract 2½ in (or 6.5 cm):

girl's height = mid-parental height - 2½ in (or 6.5 cm)

3. For a boy's future height, add 2½ in (or 6.5 cm):

boy's height = mid-parental height + 2½ in (or 6.5 cm)

You can expect a margin of error of about four inches either way. You can convert metric to imperial length units using our length calculator.

As we have already discussed, a child's height is primarily determined by genetics. However, it does not depend solely on the parents' height. It's inherited in a way so that children may be taller or shorter than their parents since height inheritance is polygenic – the answer to how tall your child will be is scattered among many genes.

## Bone age – skeletal maturity prediction

The maturity of a child's skeletal system might be estimated by using a bone age study. It consists of taking a single X-ray of the left wrist, hand, and fingers. It is a painless procedure that exposes the individual to a very small amount of radiation. Afterward, the image is compared to standard images from a bone development atlas created from studies on a large number of kids. Bone age is measured in years.

The growth of bones is possible thanks to a particular area within two ends of long bones – the growth plate. This is a hyaline cartilage plate, which consists of actively growing cells. These plates can be found in children's bones, and in adolescents, they turn into an epiphysial line (a residue of the growth plate). This replacement is called epiphysial closure or growth plate fusion. The fusions are complete in ages 12-16 for girls and 14-19 for boys.

Growth plates are easy to identify on an X-ray because they are softer and contain less mineral content than standard bone. That makes them appear darker than the rest of the skeleton on the X-ray image. They look different at each age – thanks to that, a doctor can determine bone maturity by simply reviewing its appearance. Then, the image is compared with the closest matching image from an atlas.

Observing the difference between a child's bone age and chronological age may point to a growth problem, but it is not the rule. Some kids with perfect health can have a disparity in skeletal and chronological age.

The control of bone age is done to assess the tempo of the maturing process of a child's skeleton. This allows doctors to diagnose conditions that delay or accelerate physical growth. Using the skeletal age, physicians may predict the following:

• How long the child will be still growing;
• A child's final height; and
• The start of puberty.

The study is also used to monitor the treatment process of kids with growth deficiencies. There are plenty of factors that may affect growth:

• Hormone-related diseases (adrenal gland disorders, growth hormone deficiency, hypothyroidism);
• Genetic disorders (e.g., Turner syndrome); and
• Orthopedic as well as orthodontic problems, the treatment of which must be planned according to the child's predicted growth.

## Growth charts

Standardized growth charts are an essential tool used by doctors to determine whether a child is growing as expected. They are based on regular measurements of a child's height, weight, head size, and BMI.

To find these values, you can use our BMI calculator or child BMI calculator.

The most popular charts are the WHO Charts for infants and children ages 0 to 2 and for children above 2. They are also helpful for judging the onset of puberty in an older child.

## When do girls stop growing? – average female height

The growth process differs between girls and boys. Female growth is fast in childhood, and when they reach puberty, it speeds up rapidly. They achieve adult height usually at the age of 14-15 or a couple of years after menstruation occurs the first time.

Following the growth charts from the CDC, the at age 20 is 64-65 in (163 cm). In the table below, you can find a few other numbers for different ages.

Age (years)

Median female height

4

3 ft 3 in

101 cm

6

3 ft 9 in

115 cm

8

4 ft 2 in

127.5 cm

10

4 ft 7 in

138 cm

12

4 ft 11 in

151.5 cm

14

5 ft 4 in

160.5 cm

16

5 ft 4 in

162.5 cm

18

5 ft 4 in

163 cm

20

5 ft 5 in

163 cm

## When do boys stop growing? – average male height

Boys come into puberty later than girls. They start entering it at the age of 12-15, so the most significant growth happens around two years later than for girls. The height growth rate for most boys slows down around 16 years old, but their body mass (mainly muscles) continues to develop. According to the CDC, around 20 years old is 69.5 in (177 cm). Check below for the median height of boys during their childhood and teenage years.

Age (years)

Median male height

4

3 ft 4 in

102 cm

6

3 ft 9 in

115.5 cm

8

4 ft 2 in

128 cm

10

4 ft 6 in

138.5 cm

12

4 ft 11 in

149 cm

14

5 ft 4 in

164 cm

16

5 ft 8 in

173.5 cm

18

5 ft 9 in

176 cm

20

5 ft 9 in

177 cm

## How to get taller?

Many people are not satisfied with their height. That is why they keep asking questions like how to get taller? Is it possible to increase my height? How can I grow taller as an adult? Firstly, we should consider a general question – is it possible to increase height after puberty at all?

In the text above, we found the majority of a person's height is determined by genetics (60-80%), and the body grows by lengthening its long bones (thanks to special cartilage located in long bones – growth plates). The conclusion is that it is impossible to increase bone length after the closure of growth plates. It means that a human cannot grow taller.

However, we can observe slight daily variations in height for most adults. The cause of these changes lies in spinal disc compression throughout the day. Daily activities impact the disc cartilage, which results in their height reduction. Note that we are tallest just after night and shortest at the end of a long, active day.

You may encounter myths about some techniques that will allow you to grow. Most popular activities are certain forms of exercising (e.g., weightlifting) and stretching. Unfortunately, there is no good scientific evidence to prove these methods. We recommend that you do not let it worry you, as it is something you can do seemingly nothing about.

For sure, during the childhood and teenage years, while puberty is on, a healthy lifestyle allows your kid to grow in the right way. At that time, it is very important to sleep enough, eat well (provide enough macronutrients and micronutrients to the developing body), and do sports.

Remember that Omni Calculator is not a doctor. If you believe your child is too short or too tall, please consult a pediatrician.

## FAQ

### Can identical twins be different heights?

Yes, identical twins can be of different heights. This is because a small percentage of the factors that determine height are environmental, so if one twin receives a more nutrient-rich diet, they will likely be taller, even though they are genetically the same.

### How can I increase my height?

If you are a child, eat as much as you can on a healthy diet! If you are an adult, you cannot grow anymore, but you can appear taller by maintaining good posture. Stand straight up to realize your tallest potential.

### What is the average height for a 12 year old?

The average height of a 12-year-old boy is 148.3 cm (4 ft 10 in), while for a 12-year-old girl, it is 150.0 cm (4 ft 11 in). The reason girls are slightly taller at this age is that, on average, they go through puberty earlier than boys.

### What is the average height for a 13 year old?

The average height of a 13-year-old girl is 155.4 cm (5 ft 1), and for a 13-year-old boy, it is 154.9 (5 ft 0). This data is taken from WHO growth charts, which are the international standard for height percentiles.

### When do girls stop growing?

On average, a girl will stop growing when she is around 14-15 years old. Her final growth spurt should occur roughly 2 years after her period has begun and approximately 4 years after puberty has begun.

### How do you measure height?

Here is how you measure your height:

1. Stand next to a wall with your back to it. A floor that is not carpeted will give more accurate results.

2. Remove any headwear and footwear, and stand against the wall as straight as possible. Your head, shoulders, back, and heels should all be touching the wall.

3. Using a mirror, place a hardback book or box on your head so that it forms a right angle with the wall.

4. Mark with a pencil (or sticky note so as not to mark the wall) where the bottom of the book meets the wall.

5. Measure from the mark to the floor to find your height.

### Is height genetic?

Height is said to be around 80% genetic, with the other 20% being environmental. You can think about it as genetics determining someone's maximum height, while their nutrition and other factors decide if they get there or not. Someone with a poor diet growing up will not realize their height potential.

### At what age do boys stop growing?

The average that boys stop growing is 16, but this can be as late as 18, depending on when he entered puberty. As a general rule, boys will stop growing around 4 years after they have entered puberty. They may continue to get muscular, however.

### What is the average height for a 14 year old?

The average height for a 14-year-old boy is 162.4 cm (5 ft 3), while for girls, it is 159.8 cm (5 ft 2). Expect a significant variation in height at this age. However, some people will have finished puberty, while some may not have started yet.

### What is the average height for a 10 year old?

The average height of a 10-year-old girl is 138.6 cm (4 ft 6), while for boys, it is 138.4 (also 4 ft 6). The reason for this similarity is that, at a population level, puberty hasn't begun to cause growth spurts yet, and both sexes are the same height until sexual differences occur during puberty.

Małgorzata Koperska, MD and Filip Derma
Method 1: The Khamis-Roche Height Predictor
Mother's height
ft
in
Father's height
ft
in
Child's sex
Girl
Child's age
4 years
Child's height
ft
in
Child's weight
lb
Child's future height
ft
in
Method 2: Mid-Parental Height Calculator
Mother's height
ft
in
Father's height
ft
in
Girl's future height
ft
in
Boy's future height
ft
in
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