How Much Should a 13-Year-Old Weigh?

The beginning of the teen years brings many new changes and development. While exciting, these experiences also bring confusion. Physically, teenagers will see noticeable differences in their peers. Growth occurs at such unique rates that height and weight not only vary widely per teenager but may also adjust significantly for each individual during the thirteenth year as well. This period of change may cause teenagers to ask, how much should a thirteen-year-old weigh?

A 13-year old boy who is 61 inches tall (5 foot 1 inch or 155 cm) would be considered a normal or healthy weight between 82 to 115 pounds (37 to 52 kg).

A 13-year old girl who is 61 inches tall (5 foot 1 inch or 155 cm) would be considered a normal or healthy weight between 81 to 118 pounds (37 to 54 kg). Other ages and heights would be classified differently.

A surprisingly large number of factors play into how much a teenager weighs. This variability makes it impossible to designate one number, or even a range of numbers, as exactly what a thirteen-year-old should weigh. However, a growth chart can offer some general guidance for what a typical weight might look like for a teenager. On a weight-for-age chart, the 5th to 85th percentiles show the average weight of thirteen-year olds per CDC. In numbers, the 13-year old boy’s average weight ranges from 75 to 145 pounds (lbs) and for girls 76-148 lbs.

These weight ranges do not consider many important factors and should not be used by themselves to determine health. Experts tend to use BMI measurements to categorize weight instead. BMI takes uses both the height and weight of an individual, but still does not offer a complete assessment of health as it disregards body composition, genetics, medical conditions and other important factors. Instead of targeting an arbitrary number on the scale, thirteen-year olds should focus on adopting health promoting behaviors.

Continue reading to learn more about factors that affect the weight assessments of teenagers, how to read and understand growth charts and smart choices a teenager can make for improved well-being.

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What is a Healthy Weight for a Thirteen-Year-Old?

The ideal or healthy weight of one thirteen-year-old will differ from another. Teenagers each have unique conditions and characteristics that affect their weights. Healthcare professionals may use BMI and BMI percentiles to assess weight. The formula kg/m2 determines BMI or an online calculator such as .

On a BMI-for-age growth chart, the percentiles designate BMI into categories. 

BMI percentile
Below the 5th percentile Underweight
5-84th percentileHealthy 
85-94th percentileOverweight
Greater than the 95th percentileObese

It is important to note that these categories do not represent the distinct considerations of each teenager. The BMI calculation and categories are just one of many tools used by healthcare professionals to investigate and treat the health of clients. 

BMI-for-age growth charts

Factors that affect teenage weight

Teenagers and parents need to account for a variety of factors when assessing growth as many elements contribute to changes in weight.


As a thirteen-year-old, growth spurts should not come as a surprise. A jump in the number seen on the scale may correspond naturally to a height increase. Also, heights at this age can vary pretty drastically between teens. A five-foot individual should not expect to carry the same weight as someone a half a foot or more taller. 


Males tend to need a higher number of calories than females. However, this difference is less significant before puberty. 


Puberty can begin quite early at the age of eight, yet other kids hit puberty much later. More commonly, girls go through puberty from ages 10-14 and boys from ages 12-16.

As kids mature sexually, they will also see changes in their height and weight.

Body composition

Teenagers involved in athletics may have more muscle than others. Muscle mass weighs more than fat mass, which can cause kids to see a higher number on the scale. 


Even genetics play a role with some studies showing certain genes correlate with a higher likelihood of obesity.

Socioeconomic situation

The socioeconomic situation of a family alters eating habits, extracurricular activities and other life areas that help determine weight in individuals. 


Certain environments can make weight gain or loss more likely. For example, a high stress environment can cause a kid to either eat more high calorie foods or to find it difficult to eat all together. Food desserts can also affect dietary habits with less nutrient dense foods available for consumption.

Medical conditions

Teenagers with medical conditions experience altered metabolisms that affect weight. Some examples include diabetes, thyroid disorders and cancer.

Stage of life

Teenagers often require a higher number of calories than any other time in life. This increased need for nutrition may cause weight fluctuations as teenagers figure out what their body needs. 

Understanding growth charts

Growth charts help medical professionals track weight, height and BMI. These graphs show whether measurements follow a normal curve and aids in assessment of a teenager’s health. Deviance from a pattern of growth or abnormal findings do not automatically mean something is wrong, but signal a need to look into possible causes.

The growth charts show percentile curves in darker lines that span across the chart horizontally. These curves demonstrate a normal pattern of growth. A series of measurements helps show whether a teen follows a normal pattern of growth whether at the 75th percentile or the 5th percentile.

A BMI at the 50th percentile means this teen measures at a BMI higher than 50 percent of teens their age. 

To read a growth chart:

  1. Find child’s age on the horizontal axis of the graph.
  2. Find the child’s BMI, height or weight on the vertical axis of the graph.
  3. Follow both data points to where they intersect. 
  4. Find what percentile line the point falls closest to
  5. Using past data, see if measurements follow a similar curve

Healthy weight habits for a teenager

In the end, behavior matters more than weight for a teenager’s overall well-being. Healthy lifestyle choices developed during youth improves life quality during adolescence as well as in years to come. Creating these habits also provides more achievable outcomes than pushing a body to conform to often irrelevant expectations.

1. Avoid extreme diets or exercise regimes

Applying the principle of moderation means avoiding extremes. This principle protects physical, mental and emotional health. Too much of anything, including restriction of food, exercise, consuming food, etc. harms the body. When a certain practice starts affecting other areas of life, teenagers should re-evaluate and reach out to someone who can help them create better balance. 

2. Adopt a varied and balanced eating pattern

A healthy eating pattern involves balance and variety. Balance helps teens meet their macronutrient needs while variety helps them receive a wide range of vitamins, minerals, antioxidants, fiber, phytochemicals and other health promoting food components. This means teenagers should focus on inclusion of more foods, rather than exclusion. Adding more fruits, vegetables, whole grains, lean meat, seafood, legumes (beans, lentils, soy products) nuts, seeds and unsweetened dairy increases nutrient quality of diet.

Balance can be achieved through including protein, carbohydrates and fat at eating occasions and following the MyPlate guidelines of half the plate fruits and vegetables with a quarter protein and a quarter grains.

Variety comes through trying different foods within each food group. Eat the rainbow with fruits and vegetables from purple grapes to bright orange carrots. Try some plant-based protein or seafood in addition to traditional meat focused protein. Look for ways to include all types of grains like quinoa, wild rice and bulgur. 

3. Take care of yourself

Occupying oneself with hobbies, school and other good pursuits can boost happiness. However, saying yes to everyone and everything leads to exhaustion and burnout. Take time to relax and to focus on taking care of yourself. 

Also, practice self-compassion and realize it is normal and perfectly okay to make mistakes or not live a “perfect” day. Actually, taking rest days, enjoying a treat and other choices that may not align with the idea of “perfection” are essential and allow for sustainability in making healthy lifestyle choices.

4. Ensure adequate sleep

Sleep may not always appear productive, but this time period increases the ability to perform in ways nothing else can. Teenagers need 8-10 hours of quality and consistent sleep each day. 

Adequate sleep reduces inflammation and risk of chronic disease, protects the immune system, increases mental clarity, reduces stress, improves mood and supports a healthy weight among countless other benefits.

5. Learn how to manage stress

Teenagers will find living a stress free life impossible, but managing stress is not only possible, but beneficial. Short or acute episodes of stress allow the body to respond appropriately to certain events. Prolonged periods of stress negatively impact the body with a heightened risk of chronic disease, a higher likelihood of poor dietary choices, weakened immune system and increased inflammation.

  • A teenager can manage stress by:
  • Talking to someone 
  • Prioritizing tasks
  • Setting aside time for favorite pastimes
  • Incorporating time for physical activity 
  • Ensuring adequate sleep
  • Eating a balanced diet 
  • Meditation
  • Meeting with a licensed professional as needed

6. Find ways to move each day

Studies continue to emphasize the importance of regular physical activity. Daily movement improves health outcomes in all stages of life and increases overall life quality and longevity.

The national guidelines recommend sixty minutes or more of moderate to vigorous physical activity for youth each day. This recommendation encompasses many forms of exercise and teenagers should find what form makes them happy. Sixty minutes can occur all at once but moving throughout the day is beneficial. In fact, studies show multiple ten-minute bouts of exercise can give similar health benefits to one full sixty-minute workout.

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Katherine Harmer, RDN

I'm a Registered Dietitian Nutritionist with a love for coaching others to success in their health goals, especially teenage athletes. Tennis was my sport of choice in high school. Now I'm a little bit older, a little bit smarter, and a little bit worse at tennis.

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