How Much Should a 3-Year-Old Weigh?

Our kids come in different shapes and sizes. But sometimes doubt creeps in, Is my 3-year-old small/big for their age?

It’s such a common worry for parents.

You want to know your child is healthy, growing, and developing. Weight is an easy way you can track their growth. I took the advice of medical professionals and did some research myself to answer the question; what is a healthy weight for a 3-year old? and this is what I found.

So, how much should a 3-year-old weigh? The average 3-year old should weigh 28-38 pounds (11.8Kg – 17.2kg) whether they are a boy/girl (Source). The “average” weight of a child isn’t as accurate as calculating their BMI (Body Mass Index). BMI is a much better measurement of your child’s growth and development because the formula uses weight and height.

I tend to obsess about my children’s weight too. So you are not alone. If you are really worried then I would talk to a medical professional about their weight.

If, like me, you’d like to know if their weight is normal and healthy. Let me show you a more accurate way of calculating how healthy your 3-year-old’s weight is by using their Body Mass Index.

The average weight of a 3-year-old kid

Why is the average weight not the most accurate way of calculating your child’s growth?

Because there are some issues with the way an average weight is calculated that isn’t sensitive to differences in our children. I’m not saying that knowing the average weight isn’t a useful tool for helping your 3-year-old to develop and thrive but there are more accurate tools like BMI.

Percentile charts show average weight range for a 3-year-old.

You might, like me, find it easier tracking the average weight range of your 3-year-old by using the percentile charts.

You may have seen them before, they are the ones they used to fill in when your child was a baby. As they got older I had forgotten all about them, but I recently rediscovered the percentile weight charts and find them easier to understand and track my child’s progress.

Here are the percentile charts for boys and girls:

You can also print these charts to keep track of your child’s weight at home. I have one stuck to the inside of my cupboard in my kitchen. Filling in that chart gives me tremendous peace of mind that they are growing and developing normally.

Average weight depends on average height

For example, the original average weight of a 3-year-old is calculated using an average height measurement. But what if your 3-year-old is taller or shorter than the average height?

Then it’s likely that you will get the wrong guidance for what your child’s average weight should be. That’s why the BMI calculation is more accurate because it takes your child’s height measurement into the equation.

It would be completely normal for a 3-year-old who was taller / shorter than the average height to weigh more or less than the average weight of a 3-year-old.

Weight isn’t everything

The most important consideration when checking your 3-year-olds weight is their overall health. Just because your 3-year-old weighs within the normal range for their age. This doesn’t mean they are getting the right nutrition.

If your child weighs slightly outside the normal range you shouldn’t immediately worry. As long as they have healthy habits and have a healthy diet.

If you are worried, I would go to your local doctor and discuss reasons why this could be. 

Ok, it’s time to show you the most accurate way of calculating if your child is a normal weight using the BMI (Body Mass Index).

Calculating your 3-year-old’s BMI (Body Mass Index)

Click here to calculate your 3-year-old’s BMI (Link to the calculator on CDC ‘s website)

Body mass index is a tool used by health professionals to calculate if a person’s weight is in a healthy range. It can be used for children and adults. 

It was originally invented by Lambert Adolphe Jaques Quetelet. Which is why BMI is sometimes called the Quetelet Index.

BMI was revolutionary because it also links a person’s weight to their height. BMI is a much more efficient way to calculate if your 3-year-old is a healthy weight when compared with average weight statistics.

“There are several advantages to using BMI-for-age to screen for obesity, overweight, and underweight among children and teens.”


BMI attempts to put your child into a category based on their height, age, and weight. These categories are; underweight, normal-weight, overweight, and obese. 

So is BMI Perfect?

No, BMI isn’t a perfect tool to see if your 3-year-old’s weight is healthy or not, but it is much better than just looking up an average weight for your child. It is also the most common formula used by doctors across the world to calculate whether your child is under/overweight.

Its main problem is that it doesn’t take into account the difference in weight between muscle and fat.

Muscle is much denser than fat, so it weighs more. This means that BMI doesn’t discriminate between children who have more muscle over children who have more fat.

Obviously, children who have a higher percentage of muscle compared to fat are considered healthier. Unfortunately, BMI can’t effectively show the difference between the two. 

“a child may have a high BMI for their age and sex, but to determine if excess fat is a problem, a health care provider would need to perform further assessments”


However, BMI is the most simple, accurate, and easy to use method to give you an idea if your 3-year-old’s weight is healthy or not.

Why BMI / weight is important for your 3-year-old

Checking your 3-year-old’s weight and BMI is important because weight-related problems are common and dangerous in the US today. According to the CDC;

“In children, a high amount of body fat can lead to weight-related diseases and other health issues and being underweight can also put one at risk for health issues.”


There’s a worldwide epidemic of weight problems and their damage to people’s health is significant. There’s nothing more tragic than when weight-related health problems harm children.

Obesity has never been more common worldwide than it is today. 

Between the ages of 2-19 obesity affects 18.5% of our children. This means that 13.7 million children in the United States alone suffer from it, according to the CDC.

Talking about weight to your 3-year-old

Children, even at the age of 3-years-old can be sensitive about their weight. You have to be very careful not to use negative language or overemphasize the importance of weight to your child.

If you do, this can make them unhappy and may negatively affect their mental health. I read a great article on how we should shift the focus from weight as numbers on a scale to a discussion about health. You can read that discussion here. It changed the way I talk about weight to my children.

Problems with being underweight

Although being overweight is a much bigger problem in our country today. We shouldn’t forget that being underweight can be just as bad for your health.

It can be hard for your body to function properly if it isn’t getting the right fuel and nutrients. 

The main problems for an underweight child are:

  • Growth & Development issues
  • Malnutrition
  • Anemia
  • Weaker immune system

As a parent, we need to make sure our 3-year-old is getting the right amount of nutrition. Kids can’t control what they eat. That’s why it’s our job as parents to lay the foundations for a happy and healthy lifestyle in the future, by giving them the right nutrition.

What should I do if my 3-year-old isn’t in the ideal weight range?

Stay calm and try not to discuss weight negatively in front of your child. I would then visit your doctor to make sure there aren’t any underlying conditions that could cause your child to have fallen out of the accepted weight range.

Try and be positive about your child’s body and lead by example. Calculate your own BMI and make sure you are in the healthy weight range. Children notice more than we think.

Try not to discuss weight with your child. If your child is overweight. Try and focus more on a healthy lifestyle rather than losing weight. This will set them up for future success and happiness rather than focussing on numbers on a scale.

Here are some ideas to encourage a healthy lifestyle for you and your 3-year-old:

  • Buy more healthy food and try and get rid of unhealthy food from the house.
  • Eat family meals together
  • Have distraction-free mealtimes without TV and phones so you are more mindful of what you are eating.
  • Exercise together and make it fun, play outdoor games and sports together.
  • Create healthy snacks that you can both enjoy like banana ice cream.

If you need more information for talking to your 3-year-old about weight issues then take a look at this in-depth guide produced by

Does your toddler sometimes refuse to eat? Then I have a great article for you to read about Toddler Eating Tips.

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