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Multiple-group child car seats

By Lisa Galliers

Multi-group child car seats claim to last from when your little one is a baby until they grow into a child. Read our guide to see if it's a good investment.

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What's a multi-group child car seat? 

A multi-group child car seat is exactly that. A child car seat which spans more than one group so, in theory, will last your child for a longer period of time. 

They can seem good value because they claim to last for longer, so you may only need to buy the one child car seat to span from birth to 12 years of age, or from. And some parents may find them appealing as it means only having to choose and pay for one child car seat. 

You may see multi-group seats called combination seats, or you may also spot them listed at some retailers just as a Group 1/2/3 seat, for example.

Children must use a child car seat until they're 12 years old or 135cm tall, whichever comes first

Some multi-group seats are approved to use from birth; some are approved to use from Group 1, which is the next stage seat your baby can move too when he or she outgrows their baby car seat.

But there's a big difference between a baby and a child, so can these seats really achieve the same protection as single-group seats? 

Multi-group seats - are they worth it? 

In the past, our testing has revealed that seats which try to do too much end up compromising on something. Our car seat experts think you're probably better off buying a dedicated baby car seat, then a toddler seat and then a group 2/3 child car seat, rather than choosing a multi-group, or combination, child car seat.

Children change a lot from birth to turning into a child for one seat shell to adequately provide the protection they need at each stage.

8%Parents who use a multi-group 1/2/3 car seat for their child*

We've tested some good multi-group seats, though. These are the combination seats that have set themselves apart from the rest and performed well enough to be named a Best Buy. 

Some multi-group seats we've tested don't score highly for a number of reasons, including failing to position the adult seat belt correctly on the child, or being difficult to convert between the groups, or failing to sufficiently protect the passenger when used in a particular group or mode. 

A good car seat should be able to protect your child well enough in both crash scenarios, as you can't tell what type of accident you may be involved in. And as we expect parents to use a child car seat in all the modes and groups it is designed to cover, we limit the score to the worst-case scenario.

Have your car seat expertly fitted

With any car seat you buy, it's vitally important to get it expertly fitted to your car before you buy it. This means you can ensure it fits your car properly, and can also check your child is happy to sit in it. 

6%Parents who use a car seat with an impact shield for their child*
If you're considering buying a child car seat that uses an impact shield, we feel this is especially important, as parents and members tell us not all children like being held in place with an impact shield. 

Multi-groups seats and booster cushions

Some multi-group child car seats allow you to remove the sides of the high-backed booster seat and convert it to a booster seat in Group 3 mode. A booster seat is a backless cushion that can be used as a child car seat. Essentially, this removes the protective car seat sides (Group 2) and turns the seat into a booster cushion.

A booster cushion can help to raise a child's body to a height suitable for use with the adult seatbelt. Some have ‘horns’, which can help to guide the car’s adult seat belt across your child’s tummy area.

23%10-12 year olds use a backless booster seat in their parents car*

Booster seats are temptingly cheap – some start from as little as £6 – and there’s no doubt they’re convenient. But while using any seat is better than using none at all, booster seats offer very little protection in a crash, particularly if you’re hit from the side.

Booster seats – are you breaking the law? Read our guide to find out.

How Which? tests child car seats 

Which? has been testing child car seats for over 50 years. Each car seat we review has been crash tested in two different crash test scenarios: a front crash, equivalent to a head-on collision at around 40mph, and a side crash equivalent to a car crashing into another car at around 30mph, repeated again and again, in the different ways a car seat can be used. 

We can go through as many as 20 samples of the same seat to get the final crash test result. 

Crash tests 

Our experts have specially designed the crash tests, making them more demanding than the legal minimum standard requires. They’re derived from Euro NCAP, an organisation which carries out crash testing on cars to show how well cars protect occupants in severe accidents. We perform similar tests for car seats and feel this more accurately reflects what could happen in a real crash. 

Crash test dummies 

These are wired up to record the crash forces on the most vulnerable parts of the body and accurately indicate the risk of injury a real child could have in a crash. 

Multi-group seats 

If a car seat can be used in a number of different ways and attached by different methods (Isofix or car’s seat belt), we crash test it in each format. 

Find out more about how Which? tests child car seats.

* Based on a survey of parents in February 2018 asking what car seat their child aged 10-12 years old, currently used.


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