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Isofix child car seats

The best and worst Isofix child car seats

By Olivia Howes

Article 2 of 3

Which? tests Isofix child car seats. Here are the best and worst we've tested of models still on sale.

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Isofix is a type of child car seat fitting system that should make it easier for you to fit your baby or child car seat. We test out the most popular Isofix  and other car seats, putting them through our tough crash tests. 

The best Isofix child car seats

Below, we've picked out the best and the worst from our most recent tests so you can instantly choose which to add to your Isofix child car seat shopping list. Our table below shows the top five Isofix child car seats from our tests. But do also take a look further down the page at the worst Isofix child car seats we've tested, so you can compare. 

Top scoring Isofix child car seats

Recaro Privia Isofix
Typical price £205.00
Which? score 87%
Reviewed Aug 2014
Best Buy
Overall safety rating:
5 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
5 out of 5

This baby car seat has been described by our test experts as the best seat they've ever tested, which is an impressive accolade. We've awarded it Best Buy status for its excellent five-star crash test performance. Find out which seat will help keep your baby safe while you're out and about.

Kiddy Evo-Luna i-Size
Typical price £349.00
Which? score 82%
Reviewed May 2016
Best Buy
Overall safety rating:
5 out of 5
Fitting in car:
5 out of 5
Avoiding misuse and instructions:
4 out of 5

This baby car seat could be the perfect choice if you go on long journeys in your car a lot, thanks to the position your baby is held in the seat when in the car. It looks great and it's easy to use, too.

Maxi Cosi Pebble Plus (2Wayfix base)
Typical price £389.00
Which? score 79%
Reviewed Nov 2015
Best Buy
Overall safety rating:
4 out of 5
Fitting in car:
5 out of 5
Avoiding misuse and instructions:
5 out of 5

This one is a good-quality baby car seat and a worthy Best Buy. It provides a high level of crash protection when used with its compatible Isofix base, which is why we have made it a Best Buy.

Cybex Aton Q i-Size (Base)
Typical price £340.00
Which? score 79%
Reviewed Aug 2016
Best Buy
Overall safety rating:
5 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
4 out of 5

With five-star crash protection, this top of the range baby car seat has a range of safety features which no doubt helped it's impressive performance in our tough crash tests. It's approved to the latest car seat rules, too.

Besafe Izi Kid X2 i-Size
Typical price £400.00
Which? score 79%
Reviewed May 2016
Best Buy
Overall safety rating:
5 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
4 out of 5

This combined baby and toddler car seat has some excellent features. It's approved to the latest car seat rules, gets an excellent five-star overall rating for safety based on the results of our unique crash testing, and will keep your child rearward-facing until they're around four-years old.

The lowest scoring Isofix child car seats

Below are the five Isofix child car seats that have scored least well overall in our tests. We crash test every seat we test in front and side impact crashes, test for how easy each seat is to fit and also carry out ergonomics tests to see how comfortable your baby or child's ride will be. You can find out more detail about our testing at the bottom of the page.

Lowest scoring Isofix child car seats

Diono Radian 5
Typical price £225.00
Which? score 20%
Reviewed Aug 2016
Don't buy
Overall safety rating:
2 out of 5
Fitting in car:
2 out of 5
Avoiding misuse and instructions:
1 out of 5

Some seats are instant Don't Buys because they break or there's some other serious safety failure. Other seats are so difficult to install we make them Don't Buys because the risk of doing it wrong is so high, which would compromise the safety of the seat. This seat had poor crash test results combined with being really hard to install. We made it a Don't Buy.

ABC Design Risus 0+ Isofix base
Typical price £209.00
Which? score 1%
Reviewed Aug 2014
Don't buy
Overall safety rating:
1 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
4 out of 5

This baby car seat is suitable to be used from birth up until your baby reaches 13kg in weight. It comes with a one-pull harness to make it easier to secure your little one in the seat. We've crash tested it, at higher speeds than the UK standard, and made it a Don't Buy. Find out why.

Hauck Varioguard
Typical price £120.00
Which? score 1%
Reviewed May 2015
Don't buy
Overall safety rating:
1 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
3 out of 5

This seat is approved for use from birth upwards, and can be used rearward-facing until your child is around 18kg, or about four years old. Unfortunately, the base broke during our tests so we made it an instant Don't Buy. A good results in any other test cannot make up for this failure.

Nuna Rebl
Typical price £395.00
Which? score 1%
Reviewed Aug 2016
Don't buy
Overall safety rating:
1 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
3 out of 5

i-Size seats are meant to be safer but this one, which is approved for use with babies and toddlers up to four years old (105cm), broke when we crash tested it with a dummy representing a three-year old. The metal frame broke, sending the seat backwards. The risk of injury is very high. Find out which seat it is.

Recaro Optia
Typical price £160.00
Which? score 1%
Reviewed Aug 2016
Don't buy
Overall safety rating:
1 out of 5
Fitting in car:
4 out of 5
Avoiding misuse and instructions:
4 out of 5

This child car seat has passed the regulatory tests required by ECE R44/04 to be sold as suitable for children from 9kg to 18kg. However, in our crash tests, the car seat completely detached from the Isofix base and was sent flying forwards. Find out which one you need to avoid and why.

How Which? finds the best and worst Isofix car seats

Which? crash tests every child car seat we review, using more severe crash test scenarios for frontal- and side impact than the legal requirements. For example, baby car seats approved under the older car seat rules (R44.04) do not go through a side-impact crash test.

This is why our tests find differences, and why our crash testing helps us to find the car seats that offer the best protection for your children.

Our front-crash test is equivalent to a head-on collision at around 40mph, and our side crash equivalent to two cars crashing into each other at 30mph. The crashes are repeated again and again, in all the different ways a car seat can be used. 

Crash test dummies are wired up to record the crash forces on the most vulnerable parts of the body, which our experts believe help to accurately indicate what chances of injury a real child would have in similar circumstances.

To see the full list of Best Buy car seats head over to our reviews.

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