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How to buy the right child car seat

Baby or child car seats shopping checklist

By Lisa Galliers

Article 3 of 3

Buy a child car seat with confidence. Go armed with our top tips on what to look for and how to get the right advice in store.

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Whether you're buying your child car seat from Halfords, Mothercare or an independent retailer, watch our video above and then read our checklist below to make sure you get the right car seat for your car.

The video explains the details you need to have to hand to tell the retailer and, just as importantly, the questions that a good retailer should be asking you. You can also read on for more expert advice on choosing the safest car seat for your little one.

Our child car seat reviews reveal the seats that passed Which? crash tests.

Check your child

A few simple checks before you head to the shops will help you find the most suitable seat for your child.

Measure your child

Make a note of the weight of your child and how tall they are, as this will determine what seat you’ll need to buy. Any good shop will ask for this information.

Record the weight in imperial and metric units – people often use pounds and ounces but car seats are approved for weight groups in kilograms. Weighing your child in both will avoid making mistakes when converting from one unit to another. Measure their height in centimetres.

Always get your car seat fitted by a trained expert before you buy

Tell them your child's age

Babies, toddlers and older children grow and mature at different rates, and there can be big variations between the weight and height of children of the same age. If your baby isn't with you when you go to the shops, tell the staff your baby's age as well as height and weight. 

47% of parents in our 2020 survey* thought it was true that you need to change your baby car seat to a Group 1 car seat on their child's first birthday. Many car seat experts feel this is too young to turn a baby forward-facing. i-Size (R129) baby car seats help to address this issue, as it's mandatory to keep your baby rear-facing until 15 months of age in an i-Size baby car seat. 

And our experts believe it’s better for your child to be in a lower-group seat near the top of the weight limit, than to move them up to the next car seat group too soon. 

*In March 2020, Which? surveyed 1,800 parents with children under the age of 12.

3) Check your child in his or her current car seat

If you’re changing from one seat group to the next, weight isn’t the only factor. Check the position of your child's head in relation to the top of the seat.

You should change from a rear-facing Group 0+ seat when the crown of your child's head is level with the top of the seat. A child’s delicate head is exposed to more severe injuries in a crash if it pokes up above the top of the seat.

Some baby car seats now have the option to keep your baby rear-facing until they are 18kg, 105cm or around four years of age.

For Group 1 forward-facing seats you'll need to change up when your child's eye level is in line with the top of the seat, otherwise protection in a crash won't be so comprehensive. 

Check your car

Not all car seats fit in every car. Check in your car’s manual or with the car manufacturer to see which child car seats are approved for use in your make and model of car, and don’t forget to also check for any car the seat is likely to be used in.

Before you set your heart on a particular car seat, there are a few key bits of information about your car you’ll need to find out:

Does your car have Isofix?

If you have a relatively new car, it’s likely to have Isofix mounting points (most cars made since 2002 do). These are two anchor points hidden in the padding on the back seats of the car. Some are easier to spot than others. 

Isofix is the standard system for all new cars and car seat manufacturers, designed to make installing your child safety seat quick and easy. 

If your car has Isofix, we strongly recommend you consider a compatible seat and use the mounting system. It’s usually easier to secure than by using the seatbelt, so you should have a higher chance of fitting the seat correctly.

It's important to confirm via a manufacturer fit list that an Isofix child car seat will fit your make and model of car. Some Isofix car seats will only fit in certain seating positions within a vehicle.  

2) Does your car have underfloor storage compartments in the rear?

Car seats that use a support leg, or ones that can be fixed onto a base that uses a support leg, can’t always be used in cars that have underfloor storage compartments in the back.

This is because the underfloor storage cover isn’t usually strong enough to withstand the force of a crash and would affect the performance of the seat.

If you do have these, and your car manufacturer recommends you don’t use a seat with a support leg, then your car should have a top tether mount instead. 

3) Does your car have top tether mounts?

Since November 2012 all new cars should have a top tether mounting point. This is a third anchor point for fixing a car seat, to stop the seat tipping forward in an accident, if you can’t use a seat or car seat base with a support leg.

4) Does your car have front passenger airbags?

Do not put a rear-facing baby car seat (infant carrier, Group 0+) on the front passenger seat when the airbag is activated. Your child could be seriously injured by the force of the airbag going off during a crash.

You can use the front seat with a baby car seat if you can deactivate your front passenger airbag – check your car’s instruction manual to see whether this is possible. Check with your insurer whether deactivating the airbag affects the level of your insurance cover, too.

Still need more advice about the different ages and stages of child car seats? Head over to our choosing the best car seat - getting started guide.

Consider your lifestyle

Finding the right child car seat to transport one child in a single car is relatively easy – but finding one that will fit in with the whole family’s lifestyle is more of a challenge.

Read our top tips on things to think about before heading to the shops, so that you can give the car seat fitting expert as much information as possible – it will help them choose and fit the right seat for your family’s needs.

1) Will the car seat be used in other cars?

You need to know whether the cars you most commonly use have Isofix mounts, or whether you'll need a seat that can be fitted with a seatbelt. Think about the cars used by grandparents and childminders if they will use your seat. Not all car seats fit in all cars.

2) How many children do you transport?

Fitting two or more child car seats in a car can be difficult, so make sure you mention the other children you transport regularly.

3) How tall are the parents?

Tall front-seat passengers can affect how much space there is for a rear-facing child car seat or foot prop in the back. This could affect which seat you use for your child when the whole family is travelling.

4) Make a shortlist

Take a look at our best child car seats that offer your child the best protection and are easy to install.

Having some idea of what you want in advance helps you make the right decision when you are in the store. You can check on retailer websites whether they tend to stock the seats you want in store.

5) Arrange a fitting appointment

Some retailers offer fitting services. Phone the store before you go, to find out whether you can book an appointment so you can be sure to get help from a trained child car-seat fitter with choosing a suitable seat and showing you how to fit it properly.

If the shop assistant doesn't offer you a demonstration, ask for one and then get hands-on yourself. Some stores have a rig to use for demonstrations if they can't do the demonstration in your actual car.

Take along the information you've gathered on all of the above points when you head to the store. 

Going to the retailer

Our car seat retailer investigations revealed that some retailers don’t always offer the best service, and some fitters can offer poor advice. We’ve been working with the retailers investigated to improve staff training, and we would still advise you to go and get a car seat fitted in store.

But we want you to be prepared. Make sure you:

In a good store, they should ask you several questions to help guide your purchase, including:

How much does your child weigh?

For some car seats, your child’s weight will be the deciding factor when it comes to selecting an appropriate seat. Without this information, the assistant can't give you sound advice.

Rear-facing advice

A good retailer will recommend keeping a baby rearward-facing for as long as possible. .

Despite guidelines, 9kg is far too small for a baby to go forward-facing, so challenge anybody who suggests turning your baby too soon. 

Moving a young baby to a forward-facing seat too early opens them up to the risk of serious injury in the event of an accident.

52%Parents incorrectly think it's safest for a baby to travel facing forwards from nine months old.

How tall is your child?

If you are changing from one group of seat to the next, a retailer should ask about your child's height relative to the top of the seat. If the crown of your child’s head is level with the top of their baby car seat, then it's time to move up.

For Group 1 seats, your child is ready to swap when their eyes are in line with the top of the child seat (or higher), assuming that you've already adjusted the height of the headrest as far as it can go.

You can choose a baby or child car seat based on height for those seats approved to the latest R129 (including i-Size) regulations, instead of weight.  


Many shop staff may ask your baby's age as a starting point. Make sure you tell them the weight and height, too, if you haven't already been asked. 

What cars are you planning to use the seat in?

Not all seats fit all cars and, while some car seat manufacturers list which models fit which cars, you should double-check before you buy. You can do this by checking the manufacturer’s website or when you try the car seat in your car before you buy.

Other key questions

You should also be asked about the points we've suggested to check on your car above - including whether it has Isofix, top tether and underfloor storage. If you're not asked, point out which features your car has. 

If an Isofix car seat is recommended, a fit list should be checked to ensure that the selected seat will fit in your make and model of car, and any other cars you plan to use the seat in. 

The assistant should also be able to explain the features of any seat stocked by the retailer. The best assistants also have knowledge of seats they don’t stock, so they can advise about the pros and cons of different approaches.

Demonstrating the child car seat

Once you’ve established that the seats you’re interested in are suitable for your car, ask the assistant for a demonstration on the in-store rig. This will allow you to see how the seat fits and adjusts, without the complexities of being in the confined space of a car.

Have a go at strapping your child into the seat and make sure you can adjust everything that’s likely to need adjusting during the time your child will be using it.

Adjustments are likely to include:

  • tightening the harness
  • reclining the seat to allow kids to sleep more comfortably
  • changing from rearward to forward facing (if applicable)
  • adjusting the height of the harness
  • removing and reattaching padding and inserts for infants
  • removing harnesses completely (multi-group seats)
  • adjusting headrests and any side padding.

Once you’re happy that the seat seems right for your child, ask for a demonstration in your car, so you can see that it actually fits. Trying a child seat in your own car is absolutely essential.

Sometimes, the angle of the car’s back seat or the position of its seatbelt mountings and buckles can get in the way of a good seat, making it useless.

Strap in your child and have a go at making all the adjustments. Make sure you’re happy with the fit of the seat in the car and of your child in the seat.

Again, this is your chance to ask the retailer questions before you are on your own at home with the seat and a confusing set of instructions.

Only when you’re satisfied that the seat works for you, your child and your car, are you ready to buy.

Free car seat fitting checks

Some local councils hold regular car seat fitting clinics where you can get the fitting of your seat checked by trained fitters. Look on your local council's website, or check local press for details of car seat fit clinics. 

Other organisations, such as Child Seat Safety and Good Egg Safety, also run free car seat check days around the UK.