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How we test baby car seats

By Lisa Galliers

Which? crash tests every car seat we review to reveal the ones that protect the best and the ones that don't.

Put us to the test

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Our child car seat video shows you the huge difference between a good child car seat and a bad child car seat, and talks you through how to find the safest seat for your baby.  

Be warned, the footage is quite harrowing, even though it features crash test dummies.

Which? is part of the European Test Consortium, consisting of the Worldwide Association of Consumer Organisations (ICRT) and the European car clubs. We've been testing car seats together since 2003. Which? has been testing child car seats since 1967.

We work together jointly to crash tests child car seats in two, specially designed crash scenarios using state of the art crash test dummies and sensors. 

Our crash tests are severe and our experts feel they more accurately reflect what happens in real crashes more than the legal minimum standards.


250+crash tests carried out each year

Our child car seat test results reveal big differences between seats. Some protect babies and children well, but others expose them to the risk of serious injury or even death. The best child car seats will provide protection from both front- and side-impact crashes – two of the most common types of crash.

Each car seat goes through the same tests in our labs, so you can directly compare their strengths and weaknesses.

Our child car seat reviews answer common questions like:

  • Is the car seat safe or unsafe?
  • Is it easy to fit?
  • Is the seat comfortable?
  • What else do I need to know?
  • Is there anything I should watch out for? 
  • Should I buy it?

Find out which child car seats are a Best Buy with our child car seat reviews.

Is my car seat unsafe?

Each car seat tested endures a front crash, equivalent to a head-on collision at around 40mph, and a side crash, equivalent to two cars crashing into each other at 30mph, repeated again and again, with the seat installed in the different ways it can be used.

We can go through as many as 20 samples of the same seat to get the final score for just one.

  • 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 tests, which carries out crash testing on cars to show how well cars protect occupants in severe accidents. We do a similar thing for car seats and feel this more accurately reflects what could happen in a real crash.
  • Crash test dummies These are wired up with state of the art sensors to record the crash forces on the most vulnerable parts of the body to help 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 the different ways it can be used.

Best Buy car seatsfind out which car seats performed the best in crash testing.

How easy is the seat to fit?

500fitting and usage tests carried out each year

It’s vital to ensure any car seat is fitted correctly. Any car seat, even a Best Buy, would be unsafe if it’s installed the wrong way.

Ease-of-use tests are not part of the legal requirements, but we conduct a whole range of tests on each seat to make sure that parents can fit them properly, without any risk of getting it wrong.

  • Hands-on assessments Parents get hands-on with the car seats to try to install them. This gives our experts an indication of the risks of installing a seat incorrectly; what could be forgotten or how the seat could be misused.
  • Fitting in cars Each seat is tried in three different makes and models of cars to see how easy it is to fit. Experts consider both Isofix and seat-belt modes.
  • Instructions and warning labels Instructions and warning labels are scrutinised to see whether there is anything confusing, annoying or misleading.
  • Trying out the seats Real children of different ages try out each seat, in all the cars, to help highlight any safely issues or problems using the seat on a day-to-day basis - something our dummies can't tell us.

How to fit a child car seatour handy videos help remind you how to fit your seat safely

Safe use of car seats for young babies

A lie-flat position is the best position for your baby to travel in, especially premature babies, newborns and young babies - not only for comfort, but also to help their breathing. Most people know of the two-hour rule, but we advise not to keep your baby in a car seat for any longer than absolutely necessary. 

The Baby Products Association advises parents not to use a car seat in the first four weeks of a baby's life for periods of more than 30 minutes. If it is essential to travel within the first four weeks, take regular breaks, at least every 30 minutes, and have an adult sit in the back to monitor your baby. Remove your baby from its seat for short periods before continuing with your journey. 

The best position for your baby - Which? checks

Our car seat testing includes an ergonomic assessment of each seat to make sure your child will be in the best position when travelling. Any seats that hold your baby too upright, especially baby car seats, will have points deducted. 

  • Position of the child Our car seat experts check to make sure your baby or child will be held in a good position while travelling, which is especially important for small babies.
  • Space Experts check how roomy the seat is for your child and how much space they'll have to grow, as well as how the head support padding works.
  • Space in the car How much space a car seat takes up is important, too. If it takes up too much, there may be none left over to safely transport other children, or it could impact space for the passenger in the front seat.
  • Comfort for the child This covers how much support there is for the child's legs, the padding. Also their view from the seat, as you don't want children tempted to lean forward out of their seat.

Car seat safety featuresfind out how a car seat protects your little one

Is there anything else I should look out for? 

Our experts work hard to uncover everything you need to know before splashing out on a car seat, from cleaning the covers to pointing out any issues in your car that could stop the seat working properly. 

  • Cleaning Whether it's sick, snot or puréed food, we can tell you how easy or fiddly the covers will be to remove and replace, so you know how simple it will be to get your car seat covers clean again. Some are very easy, some are a real pain.
  • Safety issues Our reviews point out potential issues you'll need to check before selecting your car seat, like underfloor storage compartments or car headrests that could stop your car seat working properly.
  • Design flaws - Some seats may be great in a crash test but have points deducted because they are not intuitive to install, or there's something in the design which makes them less easy to get a secure fit.
  • Moving between cars If a car seat is particularly heavy, we'll let you know in our review, so you can weigh this information up before you buy your car seat.

Child car seatsWhich? crash tests every car seat we review, find out which ones are the best.

Should I buy it?

Experts analyse our crash test results, ease-of-use data and ergonomic assessments to give each car seat a total test score, so you can see which are the best and worse, and directly compare models to each other.

The child car seat test score ignores price and is based on:

  • Safety (front crash; side crash; seat design, stability in the car, belt routing) 60%
  • Ease of use (installation, possibility of misuse, instructions, adjusting the seat, cleaning and workmanship) 30%
  • Ergonomic assessment (posture, comfort, space for child, support, padding, view) 10%

Baby car seat (Group 0 or 0+) Best Buys must score 79% or higher.

i-Size car seat Best Buys must score 77% or higher.

Group 1, 2 or 3 or toddler i-Size Best Buys (or any combinations of these groups) must score 74% or higher.

Any car seat scoring 40% or less will become a Which? Don't Buy.

Don't buy car seats

Any car seat scoring 40% or less will become a Don't Buy.

0% rated car seats will have performed so badly in parts of our crash tests that we will automatically downgrade the total test score to the lowest possible rating and make it an automatic Don't Buy. This can be because the seat is not up to withstanding the forces of a crash in a particular set up, or because part of the seat breaks or detaches during the crash tests. 

A good result in any other part of the tests cannot compensate for such a poor result.

Don't Buy car seats Find out which car seats you need to avoid and why

Helping keep children safer for more than 50 years

In 1966, almost 8,000 people were killed in road accidents in the UK. There was a huge push for better road safety, and the following year the motorway speed limit was fixed at 70mph, the breathalyser was introduced and the first Which? child car seat reviews were published.

We constantly review the tests we carry out on child car seats and update them as required to keep them as thorough as possible.

In 2011 we changed the car body we use for testing to more accurately reflect the current typical family car seat belt layout and design. 

In 2015, following the introduction of r129 car seat regulations in 2015, which run alongside r44.04, we revised our testing procedures and assessments again to those detailed on this page.

This means you should be aware of the date tested when you read each review and avoid direct comparisons pre-2015 reviews and those since.

Watch our video below to see how things have changed between then and now, and see how our crash tests discover the best child car seats.

As well as being at the forefront of independent safety testing of child car seats, Which? has campaigned for decades to help families travel more safely in their cars. We’ve helped usher in stricter seatbelt laws, and raise the standard for child car seat testing in the UK.


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