Child car seats: How we test child car seats

Crash test dummies for testing child car seats

Our dummies help us to measure how children of different ages could be injured in a car crash

The Which? child car seat test lab

Our child car seat testing reveals big differences between child car seats. Some protect babies and children well, but others expose them to the risk of serious injury or even death.

Which? is the only child car seat review website that actually tests child car seats in two crash simulations: a front crash, equivalent to a head-on collision at around 40mph, and a side crash.

Which? child car seat testing is unique because...

  • Our tests are based on years of testing experience
  • We don't accept adverts in our magazines or website
  • We buy everything we lab-test
  • We're completely independent of any manufacturers

Our unique, comparative lab tests mean you can trust our Best Buy and Don't Buy verdicts and choose with confidence.

Take out a £1 trial to Which? today to find out which child car seats we rated as Best Buys, or log in if you already have member access.

Video guide: How we test child car seats

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 we’re using crash test dummies.


Please enable JavaScript to access this content.

Which? testing for child car seats - exceeding the current safety standards

All seats sold in the UK must meet the test requirements of the compulsory standard ECE R44/04. This simulates a low-speed crash test at the front of the vehicle, equivalent to around 30mph, without a child sustaining serious injury. 

But the test doesn't use a realistic car, just a mock up of a car's back seat and there's no side-impact test, or ease of use assessment for child car seats.

Which? car seat testing - crash tests

Crash testing child car seats

Which? crash tests every child car seat we review

Which? uses far more stringent standards than this to test child car seats. 

Our crash tests are derived from Euro NCAP – which carries out crash testing on behalf of European consumers and shows how well cars protect occupants in severe accidents. Our testing does a similar thing for child seats and more accurately reflects what happens in real crashes than the legal minimum test.  

Which? tests are harder, so you can buy better.

Our front-crash test is equivalent to a head-on collision at around 40mph, and we also carry out a side-impact crash test. 

We propel a Vauxhall Astra car body down a track, stop it sharply and film the effects on the dummy in the seat. 

Our dummies are wired up to record the forces on the head, neck, chest and pelvis, accurately indicating what chances of injury a real child would have in similar circumstances.

The side crash reproduces what would happen if someone were to drive into the side of your car, simulating an impact speed of around 17.5mph.

Which? car seat testing - ease of use

Checking how easy a car seat is to install

We assess how easy each child car seat is to install correctly

Another omission from the legal requirements is ease-of-use tests. 

We check whether each seat is easy to install and adjust in a range of cars, considering both Isofix and seat-belt modes. And we look at the instructions to see whether there are any ambiguous areas which could lead to incorrect fitting of the child car seat.

If a seat is difficult to install, it’s more likely to be incorrectly fitted, which could increase the risk of injury, or even death, in a crash. 

It's important to note that the Which? test score only applies if you've installed the child car seat correctly. On belted car safety seats, any slack in the seat belt will severely reduce the protection they offer.

Car seat test ratings explained

All crash test and fitting data from our labs is carefully analysed by Which? staff to reveal the highs and lows of every product.

If anything does not add up with a product then we will retest it. If there's a fault we'll purchase a new product to see whether it’s a one-off issue, or symptomatic of a larger problem.

To be a Best Buy a Group 0 or 0+ child car seat must score 77% or higher. A group 1, 2, 3 child car seat (or any combinations of these groups) must score 74% or higher to be a Best Buy. 

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

  • Safety (front crash; side crash; seat design) 60% 
  • Ease of use (installation, possibility of misuse, comfort, cleaning and workmanship) 40%
Which? star ratings
Very poorvery poor

As well as ensuring you have the right child car seat, visit our car reviews to find the safest and most efficient car for you and your family. 

More on this...