The Good Egg Car Safety Blog

When is the infant car seat outgrown?


A car seat lasts until the child reaches the weight, or the height limit for the seat.  As children are all unique, the ages specified on seats should only ever be used as a guideline. The weight and height of a child is the deciding factor.

Most infant car seats available on the market are Group 0+, however, there are still a small number available that are only certified to Group 0.  You can find out what group your seat is by locating the R44 sticker on your seat.  The sticker will tell you the weight limit for your seat.

ECE label

If your label shows a weight range of:

    • 0-10kg – then it is group 0


    • 0-13kg – then it is group 0+


When is the infant car seat outgrown? When the weight limit is reached, or the top of the child’s head is level with the top of the seat.


Are their feet going to get hurt?

If your child’s feet hang over the end of the seat, it is not an indicator to move them up a stage, as is commonly believed.  Childrens' feet and legs are very unlikely become injured in a collision when they are rear facing, and they will not be uncomfortable.  Children are much more flexible than adults and will happily sit with their knees bent or their legs crossed.

Infant car seat outgrown 1


But they look squished...

A common misconception is that babies are ‘squashed’ into their car seat.  Newborn babies look swamped by the seat when they are very tiny, so naturally 9 months down the line they look huge in it!  However, so long as a baby is within the weight and height limits of the infant seat, they are very safe.

A car seat is a little like a motorbike helmet, if your motorbike helmet was loose it would not work as well as one that was a snug fit.  Car seats are the same, if a baby is snug in their car seat, they have maximum protection.  It is partly for this reason that infant seats come with newborn inserts to help support them.


Newborn cushion

Newborn cushions are normally removed at about 5-6 months of age. To learn more about newborn cushions, check out last week's post.


Adjusting your seat

Your infant seat will adjust with your child as they grow.  The newborn cushion and head hugger usually will be removed over the course of the first 6 months (remember once removed the harness will need adjusting too).  The harness will either have an adjuster or it will require you to re-thread the harness to a new height setting.  The straps must be level with or just below your baby’s shoulders.


Seat shell

The length of the car seat shell will play a big factor in how long the seat lasts.  Take a look at these images, both of the seats have a 0-13kg weight limit.


Short seat shell


Infant car seat outgrown 2

Infant car seat outgrown 3

Tall seat shell


Infant car seat outgrown 4

Infant car seat outgrown 5

A seat with a taller seat shell will last a baby longer than a seat with a shorter seat shell.  However, fitting a seat with a tall seat shell can sometimes mean the seat belt is not long enough to go around the seat.



Choosing to use a base that stays in the car for your infant seat (if you have the option) has the benefit of reducing the risk of incorrect fitment, especially if it’s ISOFIX.  It also has the secondary benefit of either eliminating the need to use the adult belt, or it routes the adult belt away from the child.  If the seat is left in the car, it makes getting the little one in and out that bit easier.

Newborn Insert 1


Travel systems

Travel systems are very convenient, but it’s very easy for babies to end up spending far too long in their seat.  Babies should only spend a maximum of 90 minutes in their seat at a time.


What about when the seat gets too heavy to carry and use on the pram?

Another trigger for moving up to the next stage is when the seat gets too heavy to carry or the seat isn’t put on the pram so often anymore.   It is worth remembering that the infant seat is a car seat first and foremost, that will keep your baby safe. It is a pram convenience second.  Once the seat is too heavy to lift with the baby in, leave it fitted in the car and lift the baby in and out of the seat.

Lots of people are not very keen on this idea, as it can be fiddly putting the little one back in the seat.  However, if you are choosing to turn forward facing next, this slight inconvenience will allow you to keep your baby in a safer seat until it is outgrown, as babies are much safer travelling rear facing.


To sum it up

Your baby has outgrown their infant seat when they hit the maximum weight limit for their seat, or when the top of their head is level with the top of the seat – whichever comes first.  Children are safest staying in the lower stage seat until it is outgrown.  This is particularly important if you choose to forward face for the next stage seat.

Subscribe image


Reusing child car seats
What is a car seat newborn insert?

Comments 1

Guest - ERF Mama on Thursday, 24 July 2014 08:22

Really easy to understand article. Good job!
I really like how the common myths are busted.

Really easy to understand article. Good job! I really like how the common myths are busted.
Already Registered? Login Here
Saturday, 02 March 2024

By accepting you will be accessing a service provided by a third-party external to

Supported By

Arnold Clark
Britax logo

Working in collaboration with

RSS logo
Police Scotland Logo
Scottish Fire
IAM RoadSmart_Logo_RGB_72dpi
Baby Products Association