In order to work out whether a baby is gaining weight in a healthy way, the World Health Organisation and Royal College of Paediatrics and Child Health growth charts were developed. There are 2 different ones. One for boys and one for girls.

It’s not about baby being healthier if they are heavier, it’s about following the growth line (called a centile) to see whether the weight gain is steady. It’s not helpful to compare your baby with other babies when it comes to weight. We are all different. Our babies are all different too.

How do you plot your baby’s weight?

Once baby has been weighed, look for the age they are along the bottom of the chart and then follow the chart upwards with your finger until you meet the line where your baby’s weight is. Then have a look at which of the centile lines it is closest too. These are the curved lines which go across the chart.

What does the centile mean?

The centiles were created by looking at lots of babies and plotting their weight. The 25th centile means 25%, or a quarter of babies in the study, were that weight or less. 50th centile was the maximum weight  of 50%, or half, of the babies. And so on. This is not a tool to compare babies, but rather to help health professionals check your baby is growing well.

So what are we looking for for your baby?

Say, for example, when your baby was born, you plotted their weight on the chart* and found they were on the line which said 25th, you want them to continue to grow along the 25th centile. It’s not a big problem if they drop a bit or go up a bit, but they need to grow along whichever centile they get to rather than keep jumping up or down the centiles. Weighing them monthly can help you to keep an eye on their weight. If you are concerned, speak to your health visitor or GP and they may suggest weighing more regularly.

Healthy Weight Gain

It is common when baby starts solids for them to change the centile (the line) they are following. The important thing is that they find a line and stick to it roughly as they grow. Their weight gain naturally slows around 5-6 months old, as you will see on the growth chart, as the curve is less steep, but the growth line (centile) will guide you as to what a healthy weight gain is.

If they drop the centiles at repeated weighing sessions, it might be an indicator that they are not getting the right nutrients. If they go up the centiles at repeated weighing sessions, it might be an indicator that they are having too much food or milk.

As ever, it’s also important to look for signs of health as well as weight. Things like plenty of wet and dirty nappies, baby being alert and active, and generally seeming well. If you have any concerns, seek advice from your GP or health visitor.

What to do if your baby is too heavy?

If you have been told your baby is too high on the centiles (usually you will be told this at the 98th centile), you may be encouraged to reduce the amount of food your baby is having. It’s really important to help your baby learn their hunger and fullness cues. Feel free to get in touch with me for more information.

Physical activity is also really important. Even before babies can crawl, we can help them move with tummy time and clapping and moving their legs. The recommendation for children is to do at least an hour of physical activity a day.


* find the age of the baby along the bottom of the chart and use your finger to go up to where your baby’s weight is. The line they are nearest to on the chart is their centile.

This article does not replace individualised medical advice.