CAR SEAT ADVICE UK
  • Car Seat Advice
  • Everything you need to know
    • Choosing the right car seat
    • Seat Types and Weight and Height Limits
    • Rear Facing or Forward?
    • Installation Methods
    • The Harness
    • The Law
    • Car Seat Testing
    • Common Errors
    • FAQ
  • Installation methods
    • Infant car seats up to 13kg or 87cm
    • Rear facing car seats up to 18kg or 105cm
    • Forward facing seats from 9-18kg or 15 months to 105cm
    • Rear and forward facing seats from 9-25kg
    • Booster seats from 15-36kg
    • Seat Belt Buckles
    • ISOfix Points, Tether Straps and Support Legs
    • Indicators and side impact protection
  • Admin Team
  • Specialist Retailers

Seat Types and
Weight and Height Limits

By law all children must travel in the car in 'an appropriate restraint'

This guide will help you decide which restraint is appropriate for your child.

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

These groups all overlap slightly. The minimum weights given are the minimum weights for which these seats have passed a crash test. But that doesn't necessarily mean that it is safe to use them that early. It is always safer to use a lower group until the maximum weight has been reached before moving to the next one. This is especially important when making the switch from rear facing to forward facing, and from five-point harness to booster seat. Group 2's 15kg is actually from three years, but we have deliberately put four, because a booster seat is not safe for a three year-old.


Group 0
Birth to 10kg
Car Seat Advice UK | Group 0 Jané Transporter
This is a car bed, which is suitable for the first six months. They are particularly good for premature babies who can suffer breathing difficulties in more upright seats. They take up two spaces in the car as they are installed sideways. Not many manufacturers make these car beds anymore, and unless the baby needs one for medical reasons, we believe that travelling backwards is safer than travelling sideways.
Group 0+
Birth to 13kg

Car Seat Advice UK | Group 0+ Maxi-Cosi CabrioFix
Rear facing infant carrier car seat, for babies from birth up to about 18 months.
Seats like this can be used until the top of the baby's head is level with the top edge of the seat.
Group 1
9-18kg

Car Seat Advice UK | Group 1 Britax King
Car seat with a five-point harness, for children aged approximately 9 months to 4 years. There are no rear facing seats available that are Group 1 only, extended rear facing seats are all combination seats which cover more than one group, which is why we used a picture of a forward facing one here. Both rear and forward facing Group 1 seats can be used until the child's eye line is level with the top edge of the seat or the shoulders no longer fit under the headrest.
Group 2-3
15-36kg

Picture
Seat belt positioning high back booster seat. The head rest can be moved up to grow with the child, and in some models the sides move outwards to give a bigger child's shoulders more room. These seats are for children aged 4 to 12. In some models the back can be removed to leave a booster cushion.
Group 3
22-36kg

Car Seat Advice UK | Group 3 Graco Booster


Seat belt positioning booster cushion. There are no seats that only cover Group 2 or Group 3, high back boosters as well as booster cushions are Group 2-3, which means these cushions are also suitable from 4 to 12 years. But they offer no side impact protection, and no comfort for a small child, which is why we have just called this Group 3.
Since early 2017 all new booster cushions have been approved for Group 3 only, and must only used by children who are taller than 125cm and weigh more than 22kg.

You should always choose a car seat according to your child's weight and size and use it up to its limits, all children are different and the age given is just a guide. Children only grow out of their car seat by weight or height, never by age.

Car Seat Advice UK | Bébé Confort Iséos
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. Even the nine month minimum forward facing age that manufacturers give is far too young. The bones in a child's neck 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. 


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 seats

Apart from Group 0+ infant seats and a few forward facing-only ones, most car seats cover more than one weight group. There are lots of different combination seats available, these are just a few examples.
Group 0-1
Car Seat Advice UK | Joie Steadi
Rear facing from birth to 18kg, forward facing from 9-18kg
Group 0-1-2
Car Seat Advice UK | Diono Radian 5
Rear facing from birth to 25kg, forward facing from 9-25kg
Group 0-1-2-3
Car Seat Advice UK | Joie Every Stage FX
Rear facing from birth to 18kg, forward facing with the five-point harness from 9-18kg, high back booster from 15-36kg.
Group 1-2
Car Seat Advice UK | Axkid Minikid
Rear facing from 9-25kg
Group 1-2-3
Car Seat Advice UK | Joie Elevate
Forward facing with the five-point harness from 9-18kg, high back booster from 15-36kg.
Group 1-2-3
Car Seat Advice UK | Impact Shield
Forward facing with an impact shield from 9-18kg, high back booster from 15-36kg. 
Impact shields are not as safe as seats with a five-point harness and we do not recommended them.
ECE R129 known as i-Size
There are a few differences between R44/04 and i-Size car seats.
Car Seat Advice UK | i-Size
  • 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 75-87cm (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 up to about four all go up to 105cm. They do still have a seat-specific weight limit which can be found on the orange sticker on the seat shell, and this limit must not be exceeded, but most children will reach the seat's height limit before they're too heavy.
  • Advanced technology 'Q' crash test dummies simulate a child’s fragile body more accurately than the dummies used for R44/04.
  • I-Size car seats have all passed a side-impact test which is not compulsory in R44/04 testing.
  • All i-Size seats are fitted into the car with ISOfix and all new cars from 2013 onwards have at least two i-Size compatible seats.
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. But if  you own an R44 seat you will be able use it for many years to come. You just won't see any new R44 designs appear in the shops.


A few examples of i-Size car seats
Birth to 85cm (13kg)
Car Seat Advice UK | Joie i-Level
Rear facing car seat from birth to about 18 months which can lie flat in the car.
40 to 83cm (13kg)
Car Seat Advice UK | Britax Baby Safe i-Size
Rear facing car seat from birth to about 18 months which can lie flat in the car. This seat can also be belt fitted without the ISOfix base.

40 to 105cm (18.5kg)
Car Seat Advice UK | Nuna Rebl Plus
Rear facing from birth to about 4 years, forward facing from 15 months to 4 years.
67 to 105cm (18.5kg)
Car Seat Advice UK | Maxi-Cosi 2WayPearl
Rear facing from 6 months to about 4 years, forward facing from 15 months to 4 years.

Some infant seats have a base that can be used for a bigger seat up to 105cm later on.
Car Seat Advice UK | i-Base Advance i-Gemm
Car Seat Advice UK | i-Base Advance
Car Seat Advice UK | i-Base Advance i-Anchor

The Orange Sticker

Car Seat Advice UK | ECE R 44/04 R129 i-Size approval stickers
All car seats have an orange approval sticker, usually on the back. This sticker tells you whether the seat meets R44/04 or i-Size, it gives the weight and height limits, and the seat's approval number. The circle with the 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.



Booster seats
The law says that children need to use a car seat until they are either 12 years old or 135cm tall. Seat belts are designed for adults and don't fit children properly. That is why older children need to sit in booster seats which guide the shoulder belt away from their neck, and the lap belt down from their abdomen onto their pelvis. If a child is 12 years old, but under 135cm tall, it is still safer for them to sit on a booster cushion. The 36kg weight limit is just given as an average. In the unlikely event that a child weighs over 36kg, but is still under 135cm, it is safer to stay on the booster until they have grown a bit taller.
On average children reach 135cm at about nine and a half, only children on the 2nd percentile take 12 years to reach that height. 150cm is more realistic for a 12 year-old and most boosters will fit up to 150cm. Don't be in a rush to stop using the booster as soon as your child hits 135cm, because that is often still too short for the adult seat belt to fit them safely.


Car Seat Advice UK | booster cushion lap belt
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  • Car Seat Advice
  • Everything you need to know
    • Choosing the right car seat
    • Seat Types and Weight and Height Limits
    • Rear Facing or Forward?
    • Installation Methods
    • The Harness
    • The Law
    • Car Seat Testing
    • Common Errors
    • FAQ
  • Installation methods
    • Infant car seats up to 13kg or 87cm
    • Rear facing car seats up to 18kg or 105cm
    • Forward facing seats from 9-18kg or 15 months to 105cm
    • Rear and forward facing seats from 9-25kg
    • Booster seats from 15-36kg
    • Seat Belt Buckles
    • ISOfix Points, Tether Straps and Support Legs
    • Indicators and side impact protection
  • Admin Team
  • Specialist Retailers