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How to Read a Baby Growth Chart During Your Baby’s First 24 Months

July 04, 2018
5 min read

Children come in all shapes and sizes, and all babies grow at their own pace. At your pediatric visits, the healthcare provider will plot your child’s growth on a baby growth chart to make sure she’s on track. The chart might look daunting, but your doctor can help you understand this useful tool and what the results mean for your little one. To make it easier, we'll show you how to read the baby growth chart and interpret the results.

What's in this article:

What Are Baby Growth Charts? Baby Boys Growth Chart: Birth to 24 Months Baby Girls Growth Chart: Birth to 24 Months When and How Is My Baby Measured? How to Read a Baby Growth Chart How to Interpret the Results What Are the Percentiles? What Happens if My Baby’s Growth Pattern Changes? What Happens if My Baby Is Above or Below the Average?

What Are Baby Growth Charts?

Baby growth charts are important tools healthcare providers use to check your little one’s overall health. The charts are used to assess how your baby is growing compared with other children of the same age and gender and to see how your child is developing over time. Growth standards are used for babies under 24 months old to check the following:

  • Head circumference (the distance around the largest part of the head, as this indicates how your baby’s brain is growing)
  • Weight-for-length
  • Weight-for-age
  • Length-for-age.

Different charts are used for boys and girls, and different charts are also used for babies younger than 24 months and for those 2 years and older.

It's helpful to know that these charts offer pieces of information that your doctor can assess in the context of other developmental milestones, the size of the people in your family, and other factors. You can find and download the charts below.

When and How Is My Baby Measured?

You probably chose a pediatrician or other children's healthcare provider while pregnant, and your first office visit will be within a few days of your baby’s birth or shortly after you leave the hospital. From the first appointment on, checking your baby’s growth will become a routine part of each visit. Your baby's checkups will be scheduled to take place every few weeks, initially, and then every few months until your baby turns 1. Your doctor will let you know if you need to visit more often and when to schedule appointments from then on. Consider your baby’s healthcare provider a partner and feel free to ask any questions you might have about your baby’s development. Each office visit is a chance get some reassurance that you’re doing a great job.

This is usually how your baby will be measured:

  • Head circumference: A soft tape measure is wrapped around the widest part of your baby’s head from above the eyebrows, passing above the ears, to the back of her head.
  • Length: Measuring the length of a wriggly baby may be tricky, but doctors and nurses are experts at this. Your provider will lay your baby on a flat table, and stretch her legs out to get an accurate measurement from the top of her head to the soles of her feet.
  • Weight: You will be asked to undress your baby, and your provider will likely use a baby scale to get the most accurate reading.
  • You might be wondering what else to expect at some of your baby’s health checks:

  • 1-month checkup
  • 2-month checkup
  • 4-month checkup
  • 6-month checkup
  • 9-month checkup
  • 1-year checkup
  • 18-month checkup
  • 2-year checkup
  • Immunization schedule

How to Read a Baby Growth Chart

Your healthcare provider will be able to help you understand your child’s results at the health visit, but here’s a quick guide on how to read these charts. It’s important to use the boy charts if you have a boy and the girl charts if you have a girl.

Head circumference: Find your baby’s age in months at the top of the chart. Only some months are numbered, but each month is represented by a vertical line. Find your baby’s head circumference measurement on the left side (measurements are provided in both inches and centimeters). Follow these horizontal and vertical lines until they intersect. In most cases, this will be on a curved line. Follow the curved line to the right until it ends, and here you’ll see a number on a white background that indicates which percentile your baby is in.

Baby growth chart for girls

In the example above, the child is a 3-month-old girl with a head circumference of 15.5 inches. This baby is in the 50th percentile, meaning half of all 3-month-old baby girls have bigger heads, and the other half have smaller heads.

Weight-for-length: Find your child’s length in inches or centimeters at the bottom of the grid. Then find your child’s weight (in pounds or kilograms) on the left side of the grid. Follow the horizontal and vertical lines of these two measurements until they intersect on the growth curve. Follow the curved line until the end to find which percentile your baby is in.

Baby growth chart for boys

In the example above, the child is a boy who weighs 10 pounds and is 21 inches long. This baby is in the 90th percentile, meaning 90 percent of baby boys this length weigh less, and 10 percent of baby boys weigh more.

Length-for-age: Find your baby’s length (in inches or centimeters) on the left side of the grid, and find your child’s age in months at the bottom of the chart. Track these horizontal and vertical lines until they intersect on the growth curve. Follow that curve until the end, where the percentiles are written on a white, shaded background.

Baby growth chart for girls length for age

In the example above, the child is an 18-month-old girl who is 30.5 inches long. This baby is in the 10th percentile, meaning 10 percent of babies her age are shorter, and 90 percent are longer.

Weight-for-age: Find your baby’s weight (pounds or kilograms) on the right side of the grid, and then find your child’s age in months at the top of the chart. Follow these horizontal and vertical lines until they intersect on the curved line. Follow that curved line until the end, where the percentiles are written on a white, shaded background.

Baby growth chart for boys length for age

In the example above, the child is a boy who is 12 months old and weighs 23 pounds. This baby is in the 75th percentile, meaning 75 percent of 1-year-old baby boys weigh less, and 25 percent weigh more.

How to Interpret the Results

Your healthcare provider is the best person to explain your child’s growth to you. Remember, the charts show the typical growth patterns for baby boys and girls, and there is a wide range of healthy results. There is no one ideal result when viewed individually, but, ideally your child would follow along the same growth pattern (the curved line) over time and have a height and weight that grow in proportion to each other.

What Are the Percentiles?

The baby growth cart shows which percentile your child is in compared with others of the same age and gender. Percentiles are shown as curved lines. For example, if your child is in the 70th percentile for length-for-age, this means 30 percent of babies the same age and gender are longer, and 70 percent are shorter.

But, this one point doesn't provide the complete picture. Your provider will assess several values over time to see the trend of how your child is growing in comparison to the average growth curve shown on the chart.

Try not to get too focused on a single number. There is a wide range of healthy sizes and lengths, and many factors influence your child’s growth, including genetics, environmental factors, nutrition, activity levels, and health problems. When babies have growth spurts also varies. For example, breastfed and formula-fed babies grow in slightly different patterns. Breastfed babies typically put on weight more slowly than formula-fed babies, and formula-fed infants typically go through a growth spurt and gain weight more quickly after 3 months of age. In terms of weight, the normal growth rate for a baby is to double in weight by 5 or 6 months and triple it by the time she’s 1 year old. Your pediatrician is the best person to explain whether your child is on track.

As your baby grows, the diaper size that fits her perfectly will change, too. Take a look at our diaper size and weight chart to make sure that your baby’s diaper fits comfortably and has no leaks or blowouts.

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What Happens if My Baby’s Growth Pattern Changes?

A different growth pattern may not indicate a problem. Your child may simply be experiencing a growth spurt, for example. Sometimes, however, a growth pattern change may signal a problem, and your child’s healthcare provider will investigate it further. For example, if your child has always been heavier or longer than 40 percent of other children the same age and gender, but is now heavier and/or longer than 80 percent of the other children, your pediatrician may look into what has caused this increased growth. Another change that may signal a problem is if your child is not getting longer and heavier at a steady rate. A healthy, well-nourished baby usually grows at a predictable rate. Any change from this rate can help your baby’s doctor detect and address any feeding, developmental, or medical issues.

What Happens if My Baby Is Above or Below the Average?

Most children fall between the 3rd and 97th percentiles. But, if not, there may be many factors at play, and your doctor will take into account whether your child is meeting other developmental milestones, for example, and the build she’s inherited from the family. Some families might have fast-growing babies, while others have slow and steady gainers. Try not to worry, and keep these individual differences in mind as you follow your child's growth. If your pediatrician determines that your baby is overweight, underweight, growing too fast, or growing too slowly, trust that your baby is in good care, and follow your doctor’s recommendations for what to do next.

The growth charts can seem overwhelming, and the results can be confusing. Try not to compare your child to others, and instead focus on all of the growing your little one has been doing. And, if the doctor says your baby’s doing great, you have no reason to worry. You’ll probably be delighted (and maybe even a little surprised) when you see how big your baby is now compared with the day she was born. If you’re interested in learning even more about your baby’s growth and development, sign up for our monthly emails.

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