Understanding Percentile

The children we see each day are all different.  They have different family histories and come from a diverse range of backgrounds.  Even being a boy or a girl plays a role in what is “normal” for them.  Despite this, one of the most common questions we hear is:

How much should my child weigh?

Everyone grows differently and what is normal for another child may not be normal for your child.  The only way to answer the question of what is “normal for your child” or “how much your child should weigh” is to work closely with your nutritionist or doctor. 

When you bring your child to a WIC appointment, one of the first things we always do is weigh and measure them.  This is so that we can see how your child is growing.  When you go back with the nutritionist, she may tell you which percentile your child is in. 

But what do those numbers really mean?

The percentile is just a number that is used to place a child in comparison to his or her peers.  There are two peer groups we are looking at when we give you those numbers:

Height/Age:  This is how short or tall your child is compared to other children of the same age.

A large number indicates that your child is taller than most children of the same age.  A small number indicates that your child is shorter than most children of the same age.  A child in the 50^th percentile is right in the middle and therefore at the average height for children of the same age.

Weight/Height:  This is how much your child weighs compared to other children of the same height

A large number indicates that your child weighs more than other children of the same height.  A small number indicates that your child weighs less that other children of the same height. 

[For Example:  Andrew is in the 75^th percentile for his height.  So, Andrew is taller than 75% of other boys his age and shorter than 25% of other boys his age, which is just fine.]

When your doctor or nutritionist gives you this number, keep in mind that normal does not equal average.  A percentile number alone cannot tell us if your child is healthy or unhealthy.  That number simply shows us where your child stands in comparison to their peers.  In other words, the percentile number is only one part of the big picture, so don’t be worried if you child falls above or below the 50^th percentile.

If you are a WIC participant and are concerned about your child’s growth, call your local WIC office and ask to speak with a nutritionist.

Valerie Marcellus, Nutritionist