Growth charts: Understanding the results (12 to 24 mo.)

What can my toddler's growth chart tell me?

Your child's growth chart can give you a general picture of how your toddler is developing physically. By comparing your child's measurements – weight, length, and head circumference – to those of other children the same age and sex and to these same measurements from previous checkups, a doctor can determine whether your toddler is growing in a healthy way.

But don't get too hung up on your child's percentiles. Although the current growth charts are a vast improvement over earlier charts, they're not the last word on how your child is doing. The most important thing is that your toddler is growing at a steady, appropriate rate, not that they're hitting some magic number.

Here you can see the chartsOpens a new window.

Why are there different growth charts, and when are they used?

A doctor assesses your child's growth in one of two ways, depending on how old your child is. The U.S. Centers for Disease Control (CDC) recommends that doctors use the charts from the World Health Organization (WHO)Opens a new window for the first 24 months of a child's life.

The WHO charts more accurately reflect how breastfed children grow. After 24 months, doctors typically switch to the CDC's growth chartsOpens a new window.

The charts from both organizations show length in inches as well as centimeters, and weight in pounds as well as kilograms. Both charts also use percentiles, which compare averages of children broken down by age.

The charts are somewhat similar, but it's possible for a child's percentile to drop after switching to the CDC's charts after 24 months. Don't worry if that happens: The percentiles are based on different data. If you have any concerns, talk to your child's doctor.

What does "percentile" mean in a growth chart?

This is easiest to explain by example. If your 18-month-old son is in the 40th percentile for weight, that means 40 percent of 18-month-old boys weigh the same as or less than your child, and 60 percent weigh more.

The higher the percentile number, the bigger your toddler is compared to other kids their same age. If your toddler is in the 50th percentile for height, that means they fall right in the middle of the pack.

Child Growth Chart Calculator

See how your child compares to other kids in height, weight, and head size.

My toddler is only in the 25th percentile. Isn't that small?

Percentile ratings in a growth chart aren't like grades in school. A lower percentile rating doesn't mean there is anything wrong with your child. Let's say both parents are shorter than average, and your child grows up to have the same stature. It would be perfectly normal for them to rank consistently in the 10th percentile for height and weight as they grow up.

What's important to remember is that your doctor is watching how your child grows, not just how much.

Keep in mind that toddlers tend to go through rapid growth spurts as well as slow periods. Your child's doctor will note individual peaks and valleys, but they'll be more focused on the overall growth pattern.

When should I worry about my toddler's growth?

It could be cause for concern if your toddler's percentile changes significantly. For example, if they've consistently been around the 50th percentile for weight and then suddenly drop into the 15th, your child's doctor will want to figure out why. There could be a medical reason for the change that needs further evaluation.

A minor illness or a change in your toddler's eating patterns might result in a smaller drop, in which case the doctor may just follow your child's growth more closely for a while.

If your toddler hasn't been sick but their weight gain is slowing down while they continue to grow in height, the doctor may suggest giving them more food during meals and snacks. You may have to go in for more frequent visits to make sure that your toddler starts gaining weight again.

There are times when gaining or losing faster than usual is a good thing. If your toddler was underweight, for example, it may be a good sign that they've gained weight so that it's more proportionate to their height.

Also, being at one end of the growth spectrum isn't always a reason to worry. For example, if your toddler is very tall and both parents are unusually tall, then it may be perfectly appropriate for them to be in the top 5 percent.

But if your child is very short and both parents are average height or taller, or if they're very slender and both parents are average weight or larger, then the doctor will make sure that there's no problem with their growth (like a hormone deficiency or genetic problem).

On the other hand, if your toddler is in the highest 5 percent for weight, the doctor will keep an eye on their growth to make sure they're gaining a healthy amount of weight. Your child's doctor may counsel you about healthy eating habits, and they'll check that there isn't a condition (like a thyroid problem) that's contributing to your toddler's weight.

If your toddler's head measurement is much smaller than average, the doctor makes sure that their brain is growing and developing normally because your child's brain growth is reflected in the size of their skull. If their head circumference is much larger than average, they'll be further evaluated to make sure they don't have excess fluid in the brain, a condition called hydrocephalus.

How is BMI used to measure my toddler's growth?

Body mass index (BMI) measures weight relative to height and helps doctors assess body fat. Currently, the CDC doesn't recommend tracking BMI in children younger than 24 months because there are many unanswered questions about using this measurement to assess the growth of kids this age. But beginning at 24 months, a doctor will measure and track your child's BMI at each checkup to see if they're a healthy weight.

Can I tell from my toddler's size now how big they'll be as an adult?

Not with certainty. Petite toddlers sometimes grow to be strapping adults, and large toddlers can become slender over the years.

A child's parents are the best indicator – are you and your partner tall, short, or average? Slender, heavy, or medium? Chances are, your toddler will be similarly built as an adult.