How we test baby and child car seats

Only Which? child car seat reviews combine safety, comfort and ease-of-use tests to help you get the best baby or child car seat. 

Which? has been testing car seats for nearly 60 years. Our crash tests go above and beyond the standard so you can be sure you're choosing the safest seat for your child.

Unlike some other websites that publish reviews, we crash-test each child car seat we test and carry out fitting checks so we can tell you which give the best protection and which you should avoid.

Which? is funded by its members and we don't accept free samples from manufacturers and buy everything from retailers. This prevents manufacturers from influencing our reviews and ensures we test the same products that you would buy from a shop.

Keep scrolling for more information on our robust testing or head straight to our round-up of the best baby and child car seats for our top recommendations.

How safe is the car seat?

Our experts have specially designed our baby and child car seat crash tests to be more demanding than the British Standard safety tests. They’re derived from the most recent crash-test scenarios by Euro NCAP, the organisation that carries out crash testing on cars, to show how well they protect occupants in severe accidents.

Our crash tests are severe. Our experts feel they more accurately reflect what happens in real crashes than the legal minimum regulation that manufacturers are required to adhere to in order to sell their products.

The minimum regulations are currently:

• Any baby or child car seat that has ECE R44/04 on the label must have been through a front crash test at 32mph, a rear impact at 18mph and a roll-over simulation test. There is no mandatory side-impact test.
• Any baby or child car seat with R129 on the label has been tested to a new regulation (also known as i-Size), and they undergo the same tests as ECE R44/04, with the addition of a side impact test at 15mph.

Each car seat Which? tests endures:

• A front crash equivalent to an offset collision at around 31mph with another vehicle travelling at the same speed. This is the type of accident that occurs most frequently in traffic. This speed is slightly slower than we've tested in previous iterations of our test programme, but we've shortened the stopping distance for the vehicle, which imparts stronger forces on the child car seat.
• A side crash equivalent to two cars crashing into each other at approximately 37mph. Regulations require speeds of just 15mph.

You may spot that our front crash-test speed is slower than those required for R44 and R129 regulations. While this is the case, the severity of the crash setup is stronger, because we test with shorter stopping distances and with the collision happening in an offset position, rather than head-on, as this is a more common scenario in crashes at this speed.

Crash tests are repeated again and again, with the seat installed in all the different ways it can be used. We can go through as many as 15 samples of the same seat to get the final score for just one.

If a car seat can be used in a number of different ways (for example, if it’s a multi-group car seat that spans different stages) or attached by different methods (Isofix or the car’s seatbelt), we crash-test it in the different ways it can be used, and these results all feed into the overall safety score.

The overall safety rating also takes into account the stability of the car seat in the car in case it seems loose or rickety, and how easy it is to thread the car’s adult seatbelt around the car seat if this is an option.

How do we choose the crash-test speed?

We are sometimes asked why we don't crash-test car seats at 70mph – the national speed limit on motorways.

A crash at this speed would most likely overload the vehicle structure, so the effectiveness of any safety features such as seatbelts, airbags and child car seats would be severely compromised.

With our crash tests we aim to find a severe enough impact that covers a large proportion of the fatal and seriously injured accidents we see, so we can make the most significant difference possible.

What separates a good result from a poor one?

Crash-test dummies 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 to a real baby or child in a crash. 

The best car seats effectively absorb the forces from the crash, cushioning the crash-test dummy so that sensor readings are at an acceptable level. 

The worst car seats will have high dummy readings, or may even come loose from its fixings and fly through the test vehicle. When this happens, it's an automatic 0% Don't Buy.

Is the car seat easy to fit?

It’s vital to ensure your car seat is fitted correctly. Any car seat, even a Best Buy, would be rendered unsafe if it’s installed incorrectly.

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.

Parents get hands-on with the car seats to try to install them. These hands-on assessments give our experts an indication of the risks of installing a seat incorrectly, what could be forgotten, or how the seat could be misused.

We scrutinise instructions and warning labels, including the increasingly popular QR codes that take you to online instructions and videos, to see whether there is anything confusing, annoying or misleading.

Real children of different ages try out each seat, in all the cars. This helps to highlight any safety issues or problems with using the seat on a day-to-day basis – something our dummies can't tell us.

We also consider how easy the car seat cover might be to clean based on whether you can remove it easily and how it can be washed, and whether the seat has any signs of shoddy workmanship.

If a car seat is particularly heavy, we'll let you know in our review and it will impact the score, as wrestling with a heavy seat can be a nightmare, especially if you're regularly moving it between cars.

What separates a good result from a poor one?

The best car seats will click or belt into position easily, with a low risk of doing it incorrectly. Some of the best seats take into account the physical nightmare that is trying to contort your body to get a wriggly toddler into a seat and strapped in without putting your back out, so swivel car seats often perform better in these tests.

The instructions will be straightforward and you won't have lots of different steps that you need to complete to get the seat set up, such as clicking on side impact bumpers or attaching additional tethers and straps.

Heavy and bulky car seats will be penalised as they're tricky to move between cars or take up lots of space in the car, potentially impacting the space available for the driver or front passenger.

Why do you rate some extended rear-facing seats as Don't Buys if they're supposed to be safer?

Rearward-facing is the safest way for babies and young children to travel in a car. We encourage all parents to keep their children rear-facing for as long as possible. Ideally until your child turns four years old.

But child car seats can become Don’t Buys even if the crash-test scores are good. That's because they are extremely difficult or overcomplicated to fit into your car.

An incorrectly fitted car seat is much less likely to adequately protect your baby or child in a collision with another car.

Go to our best extended rear-facing baby car seats guide to find out which come top in our crash tests.

How comfortable is the car seat for your child?

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.

Our car seat experts check that your baby or child will be held in a good position while travelling, which is especially important for small babies, and this includes measuring seat curvature.

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.

The amount of space a car seat takes up is important too. If it takes up too much space, there may be none left to safely transport other children, or it could reduce space for the front-seat passenger.

We also look at the child's comfort, including leg support, padding and their view from the seat, as you don't want children tempted to lean forward out of their seat.

What separates a good result from a poor one?

The best seats will have enough padding that it's comfortable for your baby or child, but not so much that it impacts on the available space as they grow into the seat. Lower-scoring seats have stingy padding or may have padding that's so bulky that your child's head will feel squashed between the headrest or obstruct their view.

Leg support and space will be sufficient but not so much that it makes the car seat bulky or takes up lots of room. Your child's view and seating position will be upright enough that they can see the world, with the option to recline the seat for extra comfort or if they fall asleep.

Which? members can filter all our car seat reviews by overall safety, ease of installation and ergonomics of our expert test results.

How we calculate the scores

Kamisha Darroux, Which? Principal scientific advisor, says:

'We regularly ask Which? members what matters most when choosing a car seat. I then use this information when developing the test programme and evaluating the data from the laboratory. Since the safety of the car seat is vital to it's core performance, it carries the most weighting compared to other elements of the test. Our members also said that ease of use is important, so we weight this highly into our scores too.'

Here are the weightings for each element of the test:

• 50% Safety 
• 40% Ease of use 
• 10% Ergonomic assessment

How we choose the products

To make sure our reviews are 100% independent, we never accept free product samples from manufacturers or brands. Instead, we invest thousands of pounds every year buying child car seats directly from major retailers.

We test around 30 new car seats each year, catering for a range of ages and price points so we can support parents throughout the time that they'll need to use a child restraint.

Lauren Temple, Which? Principal Market analyst, says:

'To make sure we're testing the car seats parents want to see, I scour the market to track the latest launches and safety technology while monitoring market trends and shifts in consumer habits. Whether it's the latest swivel car seat from Maxi-Cosi or an airbag-integrated seat from Cybex, I keep in regular and direct contact with manufacturers so that we stay ahead of the curve.'

Is it a Best Buy car seat? What our verdicts mean

As of October 2025, the percentage score car seats need to achieve to be named a Which? Best Buy are as follows:

Best Buy baby car seats

Best Buy baby car seats cover off i-Size baby seats and Group 0 or 0+ models.

Best Buy toddler car seats

Best Buy toddler car seats cover off i-Size baby to toddler, i-size toddler, i-Size toddler to child, group 1 or group +0/1 models.

Best Buy child car seats

Best Buy child car seats cover off i-Size child or group 2/3 models.

Best Buy multi-group car seats

Best Buy multi-group car seats cover off i-Size baby to child or Group 1/2/3 or any combinations of these groups.

The percentage score car seats need to achieve to be named a Which? Best Buy differs for different types of car seat because each has its own set of pros and cons that can bump up a score. 

For example, baby car seats typically have more safety features and this can bump up their scores. It's all calculated scientifically to make sure every seat is judged equally and fairly.

Don't Buy baby, toddler and child car seats

Any model that scores 45% or less will be named a Which? Don’t Buy car seat.

In 2025, we changed the way we treat car seats that are Don't Buys due to their crash-test results.

If a car seat scores so poorly in crash testing that it is a Don't Buy, we automatically reduce the total test score to 0% and attach a safety alert. This is because we believe a bad result in any part of the crash test represents an immediate threat to your child's safety.

Car seats that score so badly on the installation tests that they're a Don't Buy (but which receive good results in our crash tests) will have their score reduced to 45% but no lower than that.

This policy change is from 2025 onwards.

Our child car seat reviews, just like other Which? reviews, are for Which? members. But any models named Don't Buy car seats are given a safety alert that's free for anyone to read as we believe it's our public duty to inform all parents about any serious hazards or risks our tests have uncovered.

Do you score car seats based on the colour or pattern of the car seat cover?

No. We would never judge a car seat based on its colour or pattern. We don't care if the seat is black, red, blue, plain or floral-patterned, as long as it's safe enough to protect a child in a crash.

As mentioned earlier in this article, the test score is made up of safety, ease of use and an ergonomic assessment.

60 years of car seat testing

Which? has been helping to keep children safer in cars for nearly 60 years. The first Which? child car seat reviews were published in 1967. 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.

Our baby and child car seat experts

Running our test projects is a group effort, with several members from across the team contributing to each one. 

We thoroughly re-evaluate our testing processes every year to ensure it's useful to you, and we ask the Which? community to tell us what matters the most when choosing a new car seat. 

Here's the team that makes it happen:

Principal researcher and writer, Hannah Fox: Hannah turns the enormous amount of data, test results and feedback from our panel of parents and lab experts into in-depth and un-biased product reviews. She's reviewed thousands of baby products and her experience of writing car seat reviews means she knows exactly how to cut through the marketing jargon to spell out what makes a car seat good or bad.

Baby and child editor, Daniel Davies: Daniel goes over all our car seats content, ensuring that what you're reading is clear, easy to understand, free of confusing jargon, and exactly what you need to know about baby, toddler or child restraint systems.

Principal scientific advisor, Kamisha Darroux: Kamisha knows the car seats regulations inside and out, and has an in-depth knowledge of what happens when a car seat performs poorly in our crash testing and how that will impact the total test score. She helps to shape the car seats test programme and is a whizz at converting hundreds of lines of data into the star ratings and scores you see in the reviews.

Principal market analyst, Lauren Temple: Lauren is constantly on the lookout for the latest new launches in the car seats market to ensure we're testing the models that parents want to know about. She regularly attends press events, product launches and industry trade shows so that she knows which car seats will be launching and when.

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