Baby Growth Chart: How to Track Your Baby’s Growth From Birth to 24 Months
Key Takeaways
A baby weight and growth chart helps you see whether your child’s weight gain is broadly following their own pattern over time, rather than chasing a single “perfect” number. In the UK, measurements recorded by your midwife, GP or health visitor are plotted as centiles (percentiles) in the red book, alongside length/height and head circumference. Small week-to-week changes are common; bigger shifts across centile lines, or weight that seems out of proportion to length, are worth discussing—especially for premature babies, who may need corrected age.
Next, we’ll explain how to read the chart and what different centiles can mean.
What Is a Baby Growth Chart and Percentile?
Simply put, a percentile on a baby growth chart shows how your baby sizes up against others their age and sex. For example, if your little one is on the 70th percentile for height, they’re taller than 70% of babies like them, and a bit shorter than the other 30%.
These growth charts are trusty guides for health professionals to keep tabs on your baby’s growth and track your baby’s physical development in the Personal Child Health Record (Red Book) that is usually given to you just before or after your baby is born.
The NHS height and weight chart (and similar charts) put your baby’s measurements against a group of similar children their age, so you can keep an eye on changes and spot patterns as time goes by.
For babies from birth up to two years, baby growth charts usually track these key bits:
Weight-for-age:
This just means your baby’s weight for how old they are (weight of an average newborn helps set the baseline).
Length-for-age (height):
How long/tall your baby is for their age - are they matching the average infant length?
Head circumference:
Measuring around the biggest bit of your baby’s head is important for checking on their brain growth, using a head circumference chart.
Weight-for-length:
Checks out your baby’s weight next to how long they are, compared to the average weight for an infant.
Different charts are used for boys and girls because baby boys are usually slightly heavier and longer than girls, and they follow different growth patterns.
For babies who were born prematurely (before 37 weeks of pregnancy), different charts are used until two weeks after the original due date. After that, the standard boy or girl growth charts are used, but a correction is applied based on how many weeks preterm your baby was born.
Why Baby Growth Percentiles Matter?
A growth chart shows where your baby is compared to the average newborn and infant weight. But it doesn’t tell the full story in one snapshot:
Basically, the chart and those percentiles (weight and height) are a quick peek at how your baby’s doing, but it’s that steady pattern that really counts. Your baby’s healthcare team will use both the growth chart and their development milestones to make sure everything’s progressing nicely.
How to Read a Baby Growth Chart for Boys and Girls
Looking at a baby weight chart or growth chart can seem like you’re reading a weather map at first, but don’t worry, your health professional will guide you through it at those regular checkups. In the meantime, here's a simple guide to help you understand these growth charts for weight, length, and head circumference. Keep in mind, there are different charts for boys and girls.
Weight-for-Age Percentile
That weight-for-age chart can look confusing, but here’s the quick version:
This tells you how your baby’s weight compares to other little ones the same age. So, “60th percentile meaning” means your baby is heavier than 60%, lighter than the other 40%. This percentile helps understand average newborn weight at birth and later growth.
Tip
In the example above, the child is a boy who is 12 months old and weighs 23 pounds. According to the baby weight growth chart, this baby is in the 75th weight percentile, meaning 75% of 1-year-old baby boys weigh less, and 25% weigh more.
Length-for-Age Percentile
To determine your baby’s length-for-age percentile on the baby length chart, follow these steps:
Tip
In the example above, the child is an 18-month-old girl who is 30.5 inches long. As the growth chart indicates, this toddler is in the 10th length (height) percentile, meaning 10% of children her age are shorter, and 90% are longer (taller).
Head Circumference Percentile
To read a growth chart for head circumference and find out the percentile, follow these steps:
Tip
In the example above, the child is a 3-month-old girl with a head circumference of 15.5 inches. As the growth chart indicates, 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. To understand more about development milestones related to head growth, explore our development milestones resource.
Weight-for-Length Percentile
To determine your baby’s weight-for-length percentile on the baby growth chart, follow these steps:
This percentile helps assess how your baby’s weight compares to other children of the same length.
Tip
In the example above, the child is a boy who weighs 10 pounds and is 21 inches long. According to the growth chart, this baby is in the 90th percentile, meaning 90% of baby boys this length (height) have a lower weight, and 10% have a higher weight.
How to Interpret Baby Growth Chart Percentiles
The charts show the typical growth patterns for baby boys and girls. Most of the time, healthy, well-nourished children will more or less follow the same growth pattern (the curved line) over time.
Keep in mind, however, that no two babies are the same. Even brothers and sisters can follow different growth patterns, and there is a very wide range of healthy results. Your doctor or health visitor is the best person to explain your child’s growth to you.
Here’s what some of those chart percentiles actually mean:
5th percentile meaning?
If your baby is in the 5th percentile, it means they are smaller than about 95% of babies the same age and sex. This can be perfectly healthy if your child has always followed a lower curve, especially if genetics or family body type play a role.
85th percentile meaning?
A baby in the 85th percentile is larger than 85% of their peers and smaller than about 15%. This could mean your baby is naturally bigger, but healthcare providers also consider weight and height together to ensure growth is proportional.
10th percentile meaning?
Being in the 10th percentile means your baby is smaller than 90% of babies the same age and sex. Like other percentiles, it’s not necessarily a concern if your child is following their curve consistently and meeting developmental milestones.
60th percentile meaning?
If your child is in the 60th percentile, they’re slightly above average—bigger than 60% of babies and smaller than about 40%. This is well within the range of typical growth.
When do babies hit 30 lb?
Age and weight can vary widely. On average, many babies reach 30 pounds (around 14 kilograms) between 24 and 36 months, but this depends on their growth curve, genetics and whether they’re naturally smaller or larger. The percentile your child falls into provides better insight than weight alone.
Have a go with our Baby Growth Chart Calculator to see where your little one’s at right now:
Baby Growth Chart Calculator
Keep an eye on your baby’s height, weight, and head circumference to average growth with our simple tool.
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*Input details of your baby’s last measurements **Source: World Health Organization
Average Infant Length and Weight by Age
Wondering what a "normal" weight is for a baby of X months? Every parent does! Here’s an easy cheat sheet with the so-called averages, but remember, they just mark the middle. Your baby’s chart will follow their own story, and that’s what counts. These charts show the average birth weight and average length of an infant in the UK to help you understand the general patterns.
50th Percentile = Median “Average”
In growth data, the average refers to the 50th percentile, meaning half of babies fall below this value, and half above it.
Remember, these are averages based on the 50th percentile and don’t reflect your baby’s measurements at each stage. Every baby is different, and your healthcare professional will ensure your little one is making steady progress throughout their first year.
Downloadable Growth and Weight Charts for Boys and Girls: Birth to 24 Months
The baby growth charts used in the United Kingdom are based on the WHO (World Health Organisation) growth standards combined with the average of baby weight and growth data gathered in the UK.
Keep in mind that accurately plotting and interpreting your child’s growth using these charts takes skill and practice, so for reliable results, it should be done by your doctor or health visitor.
Download the baby growth charts here:
When to Contact a Healthcare Professional
Every baby develops at their own pace, so it's natural to wonder if yours is growing as expected. If you have any concerns, contact your baby's GP. Seek advice if:
Your GP can look over your baby’s growth chart, check for any concerns, and put your mind at ease about how well your little one is doing.
Tip
Bring any questions about your baby's growth to your regular health visitor or baby clinic appointments. These check-ups are the ideal opportunity for your healthcare professional to monitor your little one's progress and chat through any worries you might have.
FAQs at a glance
A baby growth chart tracks four standard measurements as your child grows and develops. They include weight-for-age, length-for-age, head circumference, and weight-for-length. You can plot your baby’s measurements on a growth chart to determine the percentile.
The Bottom Line
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 the growth your little one has been making.
And, if the health professionals say 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 they were born.
Your little one is a moving, grooving, and growing machine, and there’s so much to look forward to, such as watching them start to crawl and walk, hearing those first laughs, and helping them develop those fine motor skills.
As your baby hits milestone after milestone, reward yourself for all your hard work with our Pampers Club app.
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