The Age and Weight of When your Child can Stop Using a Car Seat

September 20, 2021 @ 8:25 am
Zoe Kirby
Zoe Kirby


In the UK, there are several laws surrounding babies and car seats. You can view the government rules easily and quickly by visiting their website here. But in short, there are height and age restrictions that govern when and what type of car seat your child can use.

There are rear and forward-facing car seats, forward-facing high-backed booster seats, and backless boosters that all have a slightly different legal requirement.

Rear facing until 2 years old

Under UK law a child must be rear facing until they are at least 15 months old. The weight of your baby also plays a part in getting the correct car seat and the way they are secured into it.

Size 0 & 0+ From 0-13kg – You must use a lie-flat car seat, rear facing baby carrier or rear facing baby seat with a 5-point harness.

Size 1 – 9-18kg – Baby can use rear or forward-facing baby seat using a harness or a shield but remember you can only use a forward facing if they are over 15 months regardless of weight.

Size 2 – 15kg-25kg – Rear or Forward-facing car seat or high-backed booster that uses a seat belt or harness.

Size 3 is the same as size 2 but goes all the way up to 36kg. You will vary rarely find a car seat that doesn’t cover size 2 and 3 together.

We recommend keeping your little one rear facing until they are at least 2 years old at which point swapping over to a high-backed booster seat. You could turn your baby forward facing at 15 months if your car seat uses a base that can turn them forward facing.

Forward-facing with a harness until 5+ years old

From 2-5 maybe 6 you should stick with a front facing, high backed booster seat with a 5-point harness.

These are possibly the best type of car seats to use with a 4-year-old as not only do they get your toddler ready for seating in the car seat without a booster but they are comfortable for the baby to sit in.

If you’re interested in finding the best car seats, we have put together an in-depth guide you can read here

High backed boosters, as they are better known, allow your child to freely move whilst still protecting them in the event of a crash. They are able to see out of the window and also seat their parents in the front seat which can really help in the event of a temper tantrum.

Boosters until child fits into the car’s seat

Once the child reaches 22kg or a height of 125cm you can switch them to a backless booster seat.

Previously, a child only had to 15kg to use a backless booster but safety concerns soon arose and from March the 1st 2017 any and all new backless boosters came with a 22kg minimum requirement to be used.

Using the Correct Car Seat

Using the incorrect car seat for your little one can land you with a £500 fine from the police if you are caught.

The only car seats that can be used in the UK are those approved by the EU and will have a label on them with an E inside a circle.

If a child is under 12 years of age or under 135cm then they must have some form of the car seat so make sure before that time comes you have something, as it’s illegal for your child to not have one.

Common Questions

What happens if my childs feet touch the seat?

You wouldn’t be alone if this question crossed your mind.

Children can easily bend and move their legs even if they are touching the back seat and they will be comfortable. You only need to be concerned if their legs get trapped.

What if my child slouches and flops forward?

This again is a very common thing. I have had this problem in the past and for use it was not having the straps tightened correctly. After a bit of jiggery-pokery we managed to fix this problem. 

If you find that the straps aren’t the problem then you can use a tightly rolled muslin or nappy to fill the void between the baby and crotch strap to fix the void issue.

Can my baby wear a coat in the car seat?

In short, no.

Putting your baby into their car seat with their winter coat on is a big no-no. In the event of a crash, the coat can compress and leave the baby with large amount of space between them and the straps which can cause injury or death during the accident.

Put the baby in the car seat in their clothes and cover them with a blanket during the colder months. You can also warm the car before putting them in if possible.