Family Life

Your Guide In Knowing What Is The Average Weight For A 13 Year Old

Knowing what is the average weight for a 13 year old boy or girl is something that every parent especially mom should know to track the physical growth development of their child as he or she hits his or her teenage years.


Time goes by really fast. From one moment you gave birth to a wonderful child, and then suddenly, you realize, your once baby is no longer a baby. This feeling is especially common among parents particularly us, moms, once our children hit the teenage years, which starts at 13.


While it can get overwhelming, as parents, especially as moms, our role to ensure our babies are growing well continues. At 13-years old, we must continue tracking their growth and development – apart from height, another equally important matter that we should be well-informed about is the ideal weight for our 13-year olds.


Knowing specifically what is the average weight for a 13 year old boy or girl is, is important so we’d know if our children are growing accordingly. Otherwise, we can immediately address whatever concern is hindering their growth.


Now, the average weight of a 13-year old varies depending on several factors. At 13, your child is already at the puberty stage as well, which is another factor, rather a very important factor that can significantly affect your child’s weight, as well as her appearance. Needless to say, the timing of these changes for girls and boys.


It is helpful that institutions like the Centers for Disease Control and Prevention (CDC) have set guidelines and even came up with a body mass index or BMI calculator for us to know the ideal, considered healthy weight and BMI among children and teens.


Through these guidelines, health professionals like doctors and parents as well as caregivers are able to monitor a child’s growth. Also, by having these guidelines, they are able to immediately determine if a child is underweight or overweight, and then, immediately address whatever needs to be addressed.


With that said, this article will specifically discuss what is the average weight for a 13 year old boy and girl plus the ideal BMI and other factors to consider.




It is common among parents to continue tracking their child’s growth and development up until their teenage years. While some may find it unnecessary, others find it essential still. For some, knowing what is the average weight for a 13 year old is tantamount to ensuring that their kid is growing ideally, at the same time, making sure to avoid any delay or problems when it comes to their child’s growth and development.


Now, according to experts, the ideal weight for 13-year old boys and girls differ from one another. For boys, the ideal average weight is between 75 and 145 pounds. Meanwhile, for girls, the ideal average weight at 13 is between 76 and 148 pounds. Furthermore, for boys, the 50th percentile of weight is 100 pounds, as for girls, it is 101 pounds.


Whether you are a health professional or a parent, it is important to note that anywhere between that range is considered as average, and not by itself considered as underweight or overweight.


As we have mentioned earlier, at 13, your child has already embarked at the puberty stage. That said, it greatly affects the changes particularly in the growth and development of your child. Puberty follows one of a kind timetable for every individual child. From the moment it begins, kids may grow to as much as 10 inches, and then gain muscle, fat, and bone as their bodies develop from being a child to an adult form.


Apparently, these changes may tend to happen abruptly and may involve quick weight gain that can lead to feelings of self-consciousness as kids adjust to their new bodies. While some children may begin puberty as early as 8 years old, others may not begin up until their early tends. With that, as a result, there is a wide range of considered “normal” weights, sizes as well as shapes.




Learning what is the average weight for a 13 year old boy is essential for us to know if our children is growing ideally or if they are underweight or overweight. Keeping track of our children’s weight as well as their height greatly helps so we can immediately address concerns if there’s any.


Now, according to the Centers for Disease Control and Prevention (CDC), almost 13year old boys’ weight is around 75 and 145 pounds. As earlier mentioned, the 50th percentile for weight in this group range is around 100 pounds, which means that half of 50% of 13-year old boys weigh less than 100 pounds.


If a 13-year old boy happens to have a weight that is under the 5th percentile, a healthcare professional may categorize this as being underweight, which means, something must be done in order to correct the child’s weight. Basically, depending on how critical the weight problem is, the doctor may give supplements or vitamins to help the child gain weight. But in cases when losing weight may be caused by an underlying problem, the doctor may request for a more thorough examination of the child.


Meanwhile, if a 13-year old boy in the same age group weighs more than the 95th percentile, the doctor may diagnose it as obesity and may require the child to lose weight to be able to hit the ideal average weight for his age.


However, please take note that height must also be taken into consideration when determining the average ideal weight for your child.


For your reference, here are the percentiles by weight for a 13-year old boy based on CDC’s guidelines:


5th percentile75 pounds
10th percentile80 pounds
25th percentile88 pounds
50th percentile100 pounds
75th percentile116 pounds
90th percentile133 pounds
95th percentile145 pounds





Whether you have a 13-year old boy or girl, it is equally important to keep track of their growth. Keep in mind though that the average ideal weight for boys is different from girls. Well, for obvious reasons, boys’ and girls’ bodies are made differently.


So, to address the question, what is the average weight for a 13 year old American girl, here are the details:


As we have earlier mentioned, there are several factors that can affect a child’s average weight. However, according to CDC, most of 13-year old girls have a weight between 76 and 148 pounds. As you can see, girls are expected to gain more weight compared to boys.


CDC says that the 50th percentile for weight among girls in this age group is around 101 pounds, which means that 50% of girls in this age range have a weight that is less than 101 pounds.


On one hand, if your 13-year old baby girl weight under the said the fifth percentile, a healthcare professional particularly her attending pediatrician may categorize your little girl as being underweight. Depending on the severity of the case, your child’s doctor may either address it by asking your child to eat more certain types of food or to drink vitamins or supplements to help gain weight.


On the other hand, if your 13-year old girl weighs above 95th percentile, your baby’s doctor may classify that as obesity, which means something must be done to address the excess weight – usually by changing the child’s diet.


For your reference, here are the percentiles by weight for a 13-year old girl based on CDC’s guidelines:


5th percentile76 pounds
10th percentile80 pounds
25th percentile89 pounds
50th percentile101 pounds
75th percentile116 pounds
90th percentile135 pounds
95th percentile148 pounds


Since every child is different, it is always best to discuss your child’s weight with your trusted doctor. Also, as we have earlier said, there are a lot of factors that need to be considered to be able to come up with the more specific average weight for your little girl.




Apart from knowing what is the average weight for a 13 year old is, it is also equally important that you should learn and understand the different factors that affect the ideal weight for your child.


We have mentioned this a couple of times earlier already. Thus, here are some of the usual things that can influence your teenager’s body weight:


– Height and Body Makeup


Yes, how tall your child is may also affect how heavy your child will be. Usually, taller kids are heavier compared to shorter kids. However, that is not always the case – as some kids may be shorter but weigh more. In the same way that taller kids may sometimes weigh less compared to shorter ones.


Bone density and muscle mass are two of the most important factors that have something to do with identifying a child’s ideal weight. Just so you know, there are many variations when it comes to body composition.


For instance, since muscle weighs more than body fat, a child who is more muscular has a greater tendency to weigh more compared to a child who is leaner or the kid who has more fat instead of muscles.


So, before you assume that your child is underweight or overweight, it is best to consult your doctor so he can assess your child better considering such a factor.


– Genetics


Although the overall diet, as well as activity levels of a child, play an important role when it comes to your child’s body shape as well as composition, these are also influenced by the genes that the children inherit from their parents.


Basically, it means that people from different genetic backgrounds usually have different fat distributions or body composition, which may integrally influence your child’s body shape, size, and of course, body weight.


So, if for example, parents are lean, the more likely that their child will become lean. In the same way that when parents or one of the parents are fat, the child may also acquire such body weight composition.


– Rate of Development


Puberty begins among children when they hit the age of between 8 and 14 years old. If for example, you take a sample of 13-year old kids from the same room, most likely, you will see a wide range of kids in different weights and body sizes.


Every child is different. In the same way that their progress differs from one another. Some kids may have finished the process while the others are probably just starting to go through the changes that lead to their physical maturation.


As parents, it is important that before we judge our children’s weight or compare it to kids their age, we must first look into the different factors that are affecting your child’s weight.


– Location


You must be wondering why the location is included in this list. But apparently, one of the things that may affect the average weight of a 13-year old boy or girl has something to do with where the child is from.


Where the child lives have been found to influence his or her size, height as well as weight. You might ask why that is so. Well, apparently, it has something to do with a couple of things, which include cultural practices, genetics (which we already mentioned and explained earlier), socioeconomic level, access to food, and other factors such as the onset of puberty, which is known to vary depending on geographic location all over the world.




In order to know and understand fully what is the average weight for a 13 year old boy or girl is, it is important to know the child’s body mass index or BMI. But what is BMI?


Body mass index (BMI) is a method used to be able to estimate a person’s body fat percentage. Basically, the calculation includes weight and height. A high BMI specifies high amounts of body fat. Also, it can point to an increased risk of weight-related health issues.


Looking into skinfold measurements, bioelectrical impedance, as well as underwater weighing can help to have a more accurate assessment of body fat. Nevertheless, these tests, apart from being expensive, may be very complicated. Needless to say, the results tend to correlate well with BMI.


When it comes to the calculation of BMI, it differs between children and adults. When calculating a teenager or a child’s BMI, age is taken into account. Health professionals refer to it as “BMI for age”. Meanwhile, the CDC provides a BMI calculator for children and teens. To be able to come up with a person’s BMI, a child’s height, weight, and sex are taken into account. The result will then indicate whether the weight of the person is in a healthy range or not.


BMI, just like weight, falls into percentiles, which can help health practitioners specifically pediatricians, parents, as well as caregivers determine if a child weighs a healthy amount for their age and of course, their height.


Here’s a guide to help you know the equivalent percentile on a particular assessment from the Centers for Disease Control and Prevention:


Under the 5th percentileUnderweight
5th to 85th percentileHealthy weight
85th to 95th percentileOverweight
95th percentile or overObese


To know more about body mass index, check this video from Living Better:




More than knowing what is the average weight for a 13 year old boy or girl, this information is vital so parents and healthcare practitioners can address any underlying problems affecting a child’s weight. For instance, children who fall into the overweight or obese categories may be at a higher risk of developing health conditions like high cholesterol, type 2 diabetes, or other weight-related health issues.


Having said that, BMI is not at all times the most accurate measure because it does not take into account muscle mass or other factors that might be affecting weight particularly muscles versus fat.




You already know what is the average weight for a 13 year old boy as well as a girl. Now, what’s next?


As parents especially moms, our role is to ensure our children understand what’s happening in their bodies especially at this age when puberty hits hard.


Apart from weight, there are other relevant matters that need to be addressed to ensure your child understands what’s happening. Thus, here are some of the important topics that you and your child should talk about:


– Healthy Eating and Regular Exercise


Regardless of your child’s weight is normal or not, the thing is, as early as now, teach your child about eating healthy and the importance of regular exercise. However, for children who have weight problems, it is better to talk to your child’s doctor about what’s need to be done. For instance, if your child should avoid certain types of food or should he or she must increase certain food intake.


Puberty is the best time to discuss with your kid about eating healthy and exercising regularly. It will surely help a lot especially as your child progresses to adulthood.


– Educate Your Child About Puberty


Puberty may raise a lot of questions in your child’s mind. Thus, it is important that as a parent, we explain to them that puberty is part of life, especially of normal development. Also, there are really cases when gaining weight or otherwise is part of the changes they will encounter along the way.


– Positive Self-Image


Every person’s body is unique. It comes in different shapes and sizes. It would be very helpful if you talk about your child about it and make him or her understand things. One exercise that you can do is asking your child about what he or she feels about himself or herself. At this age, our children become vulnerable and insecure. Thus, talking about a positive image is important.



Puberty is inevitable. It is a time when so many changes are happening in your child’s body including weight. Thus, it is important to take into consideration averages and percentiles especially when there is a potential risk for obesity or health-related issues.


With that said, it is really helpful to know and understand what is the average weight for a 13 year old.