Seat Types, and Weight and Height Limits

By law all children must travel in the car in a seat that is suitable for their weight, height and age

There are two car seat regulations in Europe, ECE R44 which has been around since the early 1980s (the current version is R44/04), and ECE R129 or i-Size which was introduced in 2013.


ECE R44/04 weight groups


Group 0, from 0-10kg, birth to 9 months
Group 0+ from 0-13kg, birth to 15 months 
Group 1 from 9-18kg, 9 months to 4 years 
Group 2 from 15-25kg, 3 to 7 years 
Group 3 from 22-36kg, 6 to 12 years


You should choose your child's car seat according to their weight and size, and use it up to its limits. All children are different and the age given is just a rough idea of how long you can expect a seat to last, based on an average 50th percentile child. Children only grow out of their car seat by weight or height, never by age.
But the age at which they can start using a seat is important. Some babies are very big and reach 9kg when they are very young. But even if they are big and appear strong, their skeleton is not mature enough to support their heavy head in a crash. The regulations' 9 and 15 months minimum forward facing ages are far too young. The bones in a child's neck and spine don't begin to fuse until they are two or three years old, and it takes about three years for this process to complete. So it isn't actually until they are six that their neck is strong enough to cope with the forces of a car crash. This is why it is important for children to travel rear facing for as long as possible. 
The same applies to the move from rear facing seat to high back booster. Although according to the regulations a child can go into a booster seat at 15kg or 100cm, a lot of children reach that weight or height long before they are physically strong and mentally mature enough to sit in a booster seat. We recommend rear facing until 125cm, which on average is between six and seven.

When this picture was taken this 93rd percentile baby was six months old. He already weighed 9.5kg, so legally he was 'heavy enough' to face forward. A perfect example of the fact that legal doesn't necessarily mean safe... (This car seat was a combination one which he only used rear facing.)

Combination car seats

Apart from Group 0+ infant seats, most car seats cover more than one weight group. There are lots of different combination seats available, these are just a few examples.

ECE R129 known as i-Size

There are a few differences between R44/04 and i-Size car seats.

* In an i-Size car seat all children must rear face until they are at least 15 months old, regardless of their weight.
* I-Size car seats have height limits, they don't have set weight groups like R44/04 ones do. Infant seats generally go up to around 75-85cm (the limits vary, so please check your instruction manual to check up to which height your seat can be used). I-Size car seats for older children come in three height categories, 105cm up to about four, 125cm up to about six or seven, and R129 high back boosters go up to 150cm. Harnessed seats up to 105 and 125cm do still have a seat-specific weight limit which can be found on the orange sticker on the back of the seat, and this limit must not be exceeded.
* Advanced technology 'Q' crash test dummies simulate a child’s fragile body more accurately than the dummies used for R44/04.
* R129 car seats have all passed a side-impact test which is not compulsory in R44/04 testing.
* From 2013 onwards all new cars have at least two i-Size compatible seats, and i-Size child seats are guaranteed to fit.

I-Size will eventually replace R44/04 and some people think that R44/04 car seats will become illegal and will have to be replaced when i-Size is fully implemented (probably in 2023). This is not the case. After 2023 newly designed seats will no longer be approved under R44 and will all be i-Size. R44/04 seats will no longer be available to buy, but you'll still be able to use the ones you already have for quite a few years.

A few examples of i-Size car seats


Most infant seats have a base that can be used for a bigger seat up to 105cm later on.


The orange sticker

All car seats have an orange approval sticker, usually on the back. This sticker tells you whether the seat is an R44/04 or an i-Size one, it gives the height and/or weight limits, and the seat's approval number. The circle with an E in it indicates that the seat is approved for use in Europe and the number is the country it was tested in. For example 1 is Germany, 4 is the Netherlands, 5 is Sweden, 11 is the UK, etc. Each country has its own number, but seats from any European country may be used in any other. It will say Universal meaning the seat will fit in most cars, or Semi-Universal if they have a support leg which you may not be able to use if your car has storage compartments in the footwell. The Y indicates that the seat has a harness with a crotch strap. Seats bought outside Europe which do not have this sticker are not legal in Europe and must not be used here.