Growth Chart Percentiles: How to Read Your Child’s Chart

Growth charts can look intimidating at first, especially when they’re filled with curves, numbers and percentiles. However, once you understand how growth charts work – and what actually matters – they become a helpful, reassuring tool for tracking your child’s growth, development and overall health.

Asma Khan, DO, an OSF HealthCare pediatrician, explains how to read a baby or infant growth chart, how percentiles work and when you should and shouldn’t be concerned.

What is a growth chart?

A growth chart is a tool pediatricians use to track how your child grows over time compared to other children of the same age and sex.

Growth charts help monitor:

• Weight
• Height or length
• Head circumference (in infants and young children)
• Body mass index (BMI) for older children

Growth charts are not about labeling children as “too big” or “too small.” Instead, they help your child’s provider spot trends and ensure they’re growing at a healthy, consistent rate as part of normal child development.

Baby, Child and Teen Growth Charts: What’s the Difference

You may hear growth charts referred to as baby growth charts, infant growth charts or child growth charts. The measurements used change as children grow.

“From birth to 36 months, we measure weight, length and head circumference,” Dr. Khan said. “For children age 2 and older, we focus on height, weight and body mass index.”

For teens, growth charts help pediatricians monitor growth during puberty, when rapid height and weight changes are common and expected.

Choosing the Right Growth Chart

First things first: Find the right chart. Most pediatricians in the United States use CDC growth charts, which display percentiles ranging from the 5th to the 95th percentile.

Growth Chart for Boys vs. Growth Chart for Girls

There are separate growth charts for boys and growth charts for girls because children grow at different rates and in different patterns.

After choosing either a growth chart for a boy or a girl, choose the chart that aligns with the age range of your child.

Growth Chart by Age

• Birth to 36 months
  • Weight for age
  • Length for age
  • Head circumference for age
• Ages 2 through adolescence
  • Height for age
  • Weight for age
  • BMI for age

Growth Chart by Measurement

After that, choose what measurement you want to find.

Do you want to know your child’s weight and length percentiles? Choose the length-for-age and weight-for-age chart. Do you want to know your child’s percentile for head circumference? Choose the head circumference-for-age chart.

How to Read a Growth Chart

You may look at your child’s growth chart and wonder “How do I find percentile?” or “What percentile is my baby?” Reading a growth chart is simpler than it looks.

Step 1: Find Your Child’s Age

Age is listed along the bottom or top of the chart. Draw an imaginary vertical line at your child’s age.

Step 2: Find the Measurement

Locate your child’s weight, height or head circumference on the side of the chart. Draw an imaginary horizontal line.

Step 3: Plot the Point

Where those two lines meet is your child’s data point.

Step 4: Identify the Percentile Curve

Follow the curved line closest to the point. The number at the end of that curve is your child’s percentile.

This same process applies whether you’re reviewing a weight percentile chart, height percentile chart or a combined height and weight chart.

What do percentiles mean?

A percentile shows how your child compares to other children the same age and sex.

• 75th percentile for weight means your child weighs more than 75% of children their age.
• 25th percentile for height means your child is taller than 25% of children their age.

“What’s most important is not the number itself,” Dr. Khan said. “We look for steady growth over time.”

There is no ideal percentile. Healthy children naturally fall across the entire chart.

Should I be concerned about a low or high percentile?

Parents often worry when they see a low or high percentile, but percentiles alone don’t determine health.

A child in the 5th percentile can be just as healthy as a child in the 95th percentile. Pediatricians focus on whether your child consistently follows their growth curve over time, not whether they’re above or below a certain number.

Baby Percentile Calculators

Online tools like a baby growth chart calculator, baby percentile calculator, baby weight percentile calculator or height percentile calculator can be useful for understanding the basics

However, calculators:

• Use general population data
• Don’t account for genetics, medical history or growth patterns
• Can cause unnecessary worry when viewed without context

Growth charts can be hard to interpret, so we recommend you work with your child’s pediatrician to understand your child’s full health picture.

Growth Milestones and Child Development

Growth charts are just one part of tracking healthy growth milestones. Pediatricians also monitor:

• Developmental skills
• Nutrition
• Activity level
• Family growth patterns

Babies, children and teens often grow in spurts, which is completely normal.

When should you be concerned?

While most growth variations are normal, contact your child’s pediatrician if:

• Growth suddenly drops or jumps across percentiles
• Weight or height consistently trends downward
• You have concerns about feeding, development or overall health

“The pediatrician is your best resource,” Dr. Khan said. “If you ever have questions about your child’s growth chart, ask.”