Child car seats: Choosing a child car seat Booster seats and multiple-group seats

Children grow from 9kg to 36 kg

There is a big difference between a 9kg baby and a 36kg child

All child car seats are categorised according to the child's weight. Some seats span different weight groups; these seem good value because they'll last your child for longer. 

Visit our to find the best seat for your child's weight.

Are combined group child car seats a good idea?

Generally we think you're better off buying a dedicated Group 0+ and then Group 1 seat for your child. A combined Group 2/3 seat is fine but we don't recommend backless boosters.

Group 0/1/2 child car seats

These are designed to last a child from birth to 25kg (approximately six years old).

Children change too much from birth to 25kg  for one seat shell to adequately provide the protection they need at each stage. 

We've tested some very poor Group 0/1/2 child car seats in the past, which fail to position the adult seat belt correctly on the child and could injure their neck and internal organs in a crash.

Group 1/2/3 child car seats

There are many Group 1-2-3 seats available, which can be used from nine months all the way up to 12 years (9-36kg). These allow you to secure your baby in a five-point safety harness, then convert it to a booster seat when they reach 18kg (approximately four years old).

Generally, car seats designed to span more than two groups do not provide good levels of protection in all weight groups, but there are some exceptions.

You need to pay at least £200 to get a Best Buy Group 1-2-3 child car seat. Find out about our Best Buy Group 1-2-3 child car seats.

Why we don't recommend backless booster seats and cushions

Some Group 2/3 car seats are just booster cushions. 

These raise the child's body to a height suitable for use with the adult seat belt, but the booster cushions are not as safe as with a full-length back and 'wings', which provide extra protection for the head and chest in a side-impact crash. 

Child car seat crash test video

Watch the video to see the differences - with and without the back fitted.


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The booster cushion satisfies the legal requirement for children up to 1.35m (approx. 4ft 6in) and they're cheap (about £6-£30), but the full child car seats are safer – if more expensive.

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