How we test child car seats

Child car seats

How we test child 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.

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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? crash tests child car seats in two, specially designed, crash scenarios. Our crash tests are severe and our experts feel they more accurately reflect what happens in real crashes more than the legal minimum standards.

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, in all 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 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, 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 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.

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

Not a Which? member? Sign up to a £1 Which? trial to access these and thousands of other Best Buy recommendations. 

How easy is the seat to fit?

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.

  • 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

The best position for your baby

Our testing includes an ergonomic assessment of each seat to make sure your child will be in the best position when they travel.

  • Space Experts check how roomy the seat is for your child and how much space they'll have to grow, as well as the head support.
  • 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 even 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 and their view.
  • Position of the child We check to make sure the child will be held in a good position while they travel, which is especially important for babies.

Car seat safety features - find 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. 
  • 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%

Group 0 or 0+ Best Buys must score 77% or higher.

Group 1, 2 or 3 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.

Some car seats can perform so badly in parts of our crash tests that we automatically downgrade the total test score of the seat to 0% and make it a 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