The weight of a 12-year-old child can vary by sex, height, rate of development, and other factors.

According to the Centers for Disease Control and Prevention (CDC), a 12-year-old boy’s weight usually falls between 67 and 130 pounds, and the 50th percentile weight for boys is 89 pounds.

The CDC also reports that a 12-year-old girl’s weight is usually between 68 and 135 pounds, and the 50th percentile weight for girls is 92 pounds.

If your child is in the 50th percentile for weight, it means that out of 100 children their age, 50 may weigh more than they do and the other 50 may weigh less. If your child is in the 75th percentile, it means that out of 100 kids their age, 25 may weigh more and 75 may weigh less.

As kids approach puberty, their weight can vary a lot. According to Johns Hopkins Medicine, some kids may begin puberty as early as age 8, while others don’t see changes until they are closer to 14 years old.

During puberty, children grow taller — by as much as 10 inches — before reaching their full adult height. They also gain muscle and develop new fat deposits as their bodies become more like those of adults.

All this morphing may lead to significant changes in weight and feelings of self-consciousness.

Twelve-year-old boys most often weigh somewhere between 67 and 130 pounds, with 89 pounds marking the 50th percentile.

5th percentile67 pounds
10th percentile71 pounds
25th percentile78 pounds
50th percentile89 pounds
75th percentile103 pounds
90th percentile119 pounds
95th percentile130 pounds

Girls at age 12 most often weigh between 68 and 135 pounds, with 92 pounds being the 50th-percentile marker.

5th percentile68 pounds
10th percentile72 pounds
25th percentile81 pounds
50th percentile92 pounds
75th percentile106 pounds
90th percentile123 pounds
95th percentile135 pounds

Determining how much a 12-year-old should weigh can be trickier than plotting numbers on a chart. Several factors affect appropriate weight for 12-year-old children.

Rate of development

When puberty begins, a child’s weight can change rapidly due to increases in height, muscle mass, and fat stores.

Since puberty can start any time from age 8 to 14, some 12-year-olds may have finished the process while others are just starting or won’t begin puberty for another couple of years.

Height and body makeup

Your child’s height factors into their weight as well. Taller kids may weigh more than their shorter peers, but this isn’t a hard-and-fast rule. Body shape, muscle mass, and frame size all play a role in weight, too.

For example, an athletic child who has more muscle than fat may weigh more because muscle weighs more than fat. On the other hand, a leaner child may not have much muscle or fat and may be on the lighter end of the scale.


A child’s height, body mass, and other body features are also influenced by genes inherited from parents. This means that regardless of the child’s diet and exercise habits, their weight may be somewhat predetermined.


Where a child grows up may also affect their weight and overall body size. Puberty begins at different ages across the globe. For example, on average, puberty begins earlier in northern Europe than in southern Europe, possibly due to obesity rates and genetic factors.

In other areas of the world, weight may be affected by factors like socioeconomic level and access to food. Cultural practices play a role, too.

Doctors use a formula called body mass index (BMI) to find out if a person’s weight is in a healthy range. BMI is a way of figuring out how much body fat a person has based on just their weight and height.

BMI has some limitations, because it doesn’t account for factors like body composition (muscle versus fat) and frame size. BMI percentile calculation for children and teens takes into account age and sex and is called BMI-for-age.

The CDC offers an online BMI calculator specific to children and young adults ages 19 and younger. You just need to enter your child’s age, sex, height, and weight.

The results correspond with CDC growth charts and are ranked by percentile.

UnderweightLess than 5th percentile
Normal or “healthy” weight5th percentile to less than 85th percentile
Overweight85th percentile to less than 95th percentile
Obese95th percentile or greater

Why this information is important

Your child’s pediatrician uses BMI-for-age to track your child’s growth from year to year. This is important because a BMI in the overweight or obese range may put your child at risk of developing health issues like type 2 diabetes, high cholesterol, or high blood pressure.

Kids who are overweight are also more likely to be overweight as adults.

Using this information, you can work with your child’s doctor to help your child reach or maintain a healthy weight.

Puberty can be an emotional time for kids as their bodies and hormones change dramatically in a short time. They may have a lot of new feelings or insecurities and may not know how to articulate them to you.

It may be helpful to sit down with your child — even before they come to you with questions — to explain what puberty is and what it means with regard to the changes they’ll experience.

Explain that people come in different shapes and sizes

Creating a positive body image begins with understanding that not everyone should be held to the same standard of beauty. You may even consider asking your child to make a list of things they like about themself — physical and otherwise.

Address what your child sees in the media

Images on television, in magazines, and on social media contribute to peer pressure and promote a certain “ideal” body type that may not be healthy for everyone.

Take a look at your self-esteem around body issues

Model positive behaviors that you hope to see your child emulate. Talk about positive attributes of yourself and your child that go beyond the physical.

Remind your child that they are not alone

Remind them that everybody goes through the changes of puberty. Also tell them that not everyone will experience those changes at the same time. Some kids may start earlier, while others start later.

Keep the lines of communication open

Tell your child you are available whenever they need to talk and for whatever they want to talk about.

Eating a balanced diet will contribute to healthy growth and development in kids of any weight.

Make an effort to offer your child whole foods, including fruits, vegetables, whole grains, low-fat dairy, lean protein, and healthy fats, if those foods are available to you.

Don’t dwell on numbers, but try to make sure your child eats an appropriate number of calories each day.

Active 12-year-old boys should consume 2,000 to 2,600 calories. Somewhat-active boys should consume 1,800 to 2,200 calories. Boys who are not as active should consume 1,600 to 2,000 calories.

For girls, these ranges are 1,800 to 2,200; 1,600 to 2,000; and 1,400 to 1,600, respectively.

Encourage your child to eat mindfully and to listen to their body’s cues for hunger and fullness. Paying attention to the body’s signals helps prevent overeating.

It may be helpful to tell your child to ask themself “Am I hungry?” before snacking and “Am I satisfied?” while snacking.

Begin to educate your child about portion sizes and the importance of avoiding distractions while eating.

Make sure your child isn’t skipping meals or getting too busy to eat enough calories to fuel their development.

If you have concerns about your child’s weight, contact their pediatrician, who has been regularly recording weight at office visits and can explain the percentiles as they apply to your child.

Otherwise, remember that puberty is a time of great physical change that happens on a different timeline for each child. Listening to your child’s concerns and being open and honest about body changes can help create healthy habits that stick for life.