How To Read A Baby Growth Chart

Now that you’ve become a parent, you might want to track your little one’s growth. To aid this need, there’s a tool called a baby growth chart which allows the paediatrician to plot your child’s progress. At first, reading the baby growth chart can be a little daunting. But you can ask your doctor to help you understand this useful tool and what the results mean for your little one. In the meantime, to make things easier, we'll show you how to read the baby growth chart along with other facets like the baby weight percentile.

What Are Baby Growth Charts?

Baby growth charts are important tools doctors 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.

Baby Boys Growth Chart: Birth to 24 Months

Baby Girls Growth Chart: Birth to 24 Months

When and How Is My Baby Measured?

You probably chose a paediatrician or other children's doctor 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 one. 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 doctor a partner and feel free to ask any questions you might have about your baby’s development. Each office visit is a chance to 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 doctor 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 doctor 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:

How to Read a Baby Growth Chart

Your doctor 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 centimetres). 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.

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 centimetres 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.

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 centimetres) 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.

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.

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 doctor 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 with 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 chart 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 doctor 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 vary. 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 one year old. Your paediatrician is the best person to explain whether your child is on track.

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 doctor 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 paediatrician 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 paediatrician 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 Bottom Line

Understanding how to read the baby growth chart and decoding the results can be a little overwhelming. But you need to keep in mind that every child is different and develops at his own pace. So, try avoiding any kind of comparison between your child’s growth to that of others. Rather, cheer for his achievements. In case you have any concerns related to his development, you can always consult with his doctor. Worry not, your precious little one is born to be a champ, in his own ways!

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