What is the Average Weight for a 13-Year-Old?

Written by Judith K. Tingley

23 August, 2018

Average Weight: Is That a Thing?

What is meant by “average”? No one is really average, after all. Still, teens who are entering the stormy seas of adolescence look to their peers, family and social media for cues to their own development. These teens often set “average” as a goal to be achieved, since to be average means that the changes they are undergoing are normal, not freakish or weird. Yet, the experts, who take into account a number of variables, say that the “average” weight of a normal 13-year-old girl can fall between 82 to 137 pounds, and, for a boy, between 80 to 135 pounds—quite a wide range! In fact, the experts at Johns Hopkins Children’s Hospital report: “Because some kids start developing as early as age 8 and some not until age 14, it can be normal for two kids who are the same gender, height and age to have very different weights.”

Boys: Average Height and Weight
Age	Height	Weight
2 years	2 ft 11 in	30 lb 10 oz
3 years	3 ft 2 in	31 lb 12 oz
4 years	3 ft 4 in	36 lbs
5 years	3 ft 7 in	40 lbs 8 oz
6 years	3 ft 9 in	45 lb 8 oz
7 years	4 ft	50 lb 8 oz
8 years	4 ft 2 in	56 lb 8 oz
9 years	4 ft 4 in	63 lbs
10 years	4 ft 6 in	70 lb 8 oz
11 years	4 ft 8 in	78 lb 8 oz
12 years	4 ft 10 in	88 lbs
13 years	5 ft 1 in	100 lbs
14 years	5 ft 4 in	112 lbs
15 years	5 ft 7 in	123 lb 8 oz
16 years	5 ft 8 in	134 lbs
17 years	5 ft 9 in	142 lbs
18 years	5 ft 9 in	147 lb 8 oz
19 years	5 ft 9 in	152 lbs
20 years	5 ft 10 in	155 lbs

Data from the CDC

Accounting for the Variables

Attempting to figure out a precise average weight for any group of people is bound to be pretty much meaningless, due to variations in height, bone density, body type, gender, genetic makeup and muscle mass. The “average” in one region could vary significantly from another because of differences in diet, nutrition and cultural norms. Family is also important, especially when it comes to a child’s self-image; what is “average” in his family may well determine a teen’s sense of what’s average in general.

To add to the confusion is that kids in their early teens are prone to growth spurts, weight gains or losses, changes in bone and muscle composition, as well as changes in fat distribution. How can parents figure out where their child falls on the “average” scale? What’s important to consider is not just the child’s weight, but her body-mass index, or BMI.

Calculating and Evaluating Your Teen’s BMI

The Ideal Body Weight for a 7-Year-Old

Learn More

The U.S. Centers for Disease Control and Prevention has established body-mass indices for teens that are more reliable measures than any one “average” figure could be, since they account for the percentage of body fat, not simply weight alone. The CDC provides a simple tool for calculating your child’s BMI based on age, height, weight and gender. Once you have the BMI number, you can plot it on the appropriate CDC body mass index-for-age chart and see what percentile it falls into.

These BMI charts are easier to read than you might think at first glance; all you have to do is follow the CDC’s directions. A child whose BMI is equal to or greater than the 5th percentile and less than the 85th percentile is considered to have a healthy weight for his or her age. As you can see, this allows for a wide range of “healthy” weights. A child at or above the 85th percentile but less than the 95th percentile for his or her age is considered overweight. A child at or above the 95th percentile is considered obese. A child below the 5th percentile is considered underweight.

For example, both 13-year-old girls and boys with a BMI score of 18 are well within the normal range at slightly under the 50th percentile. Boys and girls with BMI scores of 30 are considered to be obese, while scores of 15 are rated as a bit underweight. This may look as though the difference between boys and girls is negligible; still, always use the appropriate chart to ensure the most accurate reading. If you’re concerned that your child’s BMI number seems to indicate that he or she is either overweight or underweight, consult with your family doctor. She may refer you to a dietitian who specializes in teen nutrition.

Under the Influence

Teens receive mixed signals from their surroundings. Girls see images every day of impossibly thin models traipsing across the media landscape. When looking at the gaunt, spooky chicks who inhabit the fashion pages, who would blame a teenager for thinking that these girls are, in fact, “average” examples of teen girlhood? Boys are inundated with images of macho sports figures while, at the same time, they’re encouraged by their social environment to just sit at home gaming all day.

Teens eat a whole lot of junk food, too, even though they’re under pressure to reach unrealistic weight goals. No wonder it’s hard for teens to arrive at some sense of what’s normal amidst these conflicting influences, not to mention all the changes going on in their own bodies. Such contradictions can lead to desperate measures and diets that are terribly unbalanced. Girls especially are prone to serious conditions such as bulimia and anorexia. And yet the stark reality is that too many kids are going through adolescence with the added burden of being dangerously overweight. In fact, long-term studies of BMI results show that approximately one in five children and adolescents in the U.S. are not simply overweight, but actually obese.

Your “Average” Teen

Growth Charts for Determining Normal Teen Weight

Learn More

Adolescence is a tough time; everyone agrees. And it’s made even tougher by doubts and fears about weight and body image. Teens who have grown up in an atmosphere that encourages self-acceptance and healthy habits will have a better chance of surviving the tribulations of their age—without succumbing to a phony idea of what is “average.”