Car seats are confusing to buy. There's so much jargon to understand, everything from Isofix to i-Size, and booster seats to car seat bases.
In this guide we'll round up some of the top models and explain everything you need to know to get you started on buying the safest baby or child car seat.
Table last checked: February 2023
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Watch our comprehensive video to learn about car seat groups and i-size car seats, when you need to move up to the next child car seat, tips for shopping, fitting more than one car seat in a car and much more.
All children need to use a car seat from birth until 12 years old (or until they are 135cm tall, whichever they reach first).
Child car seats are designed to protect children's soft bones and vulnerable internal organs at each stage of development.
Babies need different levels of protection to toddlers and older children, so when you’re buying your first newborn or baby car seat you need to make sure you're getting one that is suitable specifically for newborns and younger babies.
The car seat you buy needs to meet EU standards. Your child needs to be in the correct category of seat for his or her age and size. All babies start off in a rearward-facing infant car seat.
You'll need to decide whether you want an infant carrier that can be used a part of a travel system on a pushchair, and you'll also need to consider whether you want a car seat that can be secured to the car by Isofix connectors, the car seatbelt or a base.
Child car seats are bought in two ways: either according to your child's car seat weight group or according to the height of your child. So Group 0+ is from 0-13kg and an i-Size baby car seat is from 40-85cm – that's from birth to about 12-15 months old.
It's possible to buy seats that combine one or more groups, for example group 0+/1, 0-18kg, 40-105cm, or from birth to around four-and-a-half-years old. These are known as multi-group or combination seats.
Find the correct one for you from the different car seat groups.
i-Size is part of R129, a regulation for child car seats that was introduced in 2013. The idea behind i-Size is that all car seats with the i-Size logo will fit in all i-Size approved cars.
Your car and your car seat must have Isofix, a fitting system that attaches car seats directly to the frame of your car using connectors (either on an isofix base or on the seat itself).
i-Size/R129 seats are based on a child's height (instead of weight). The new seats don't replace the weight-based seats at the moment, they just give you an alternative.
Read more about why an i-Size car seat might be best for you.
Experts agree that the safest way to transport babies is in a rearward-facing infant carrier or baby car seat. A good baby car seat will help to protect your baby in both frontal and side-impact crashes.
However, lie-flat or carrycot car seats can be a good solution for newborns, especially premature babies or those with medical conditions, who need to be transported lying flat.
Some carrycot car seats are suitable only for babies up to 10kg, which means parents might change to a forward-facing next-stage seat too early.
Our advice would be to look out for a modular system – one that uses a base which is also compatible with a rear-facing baby car seat and then a rear-facing toddler seat.
If you're using a carrycot car seat, you should:
i-Size baby, Group 0 and 0+ car seats are designed to keep your little one safe in the car, not as somewhere for them to sleep for long periods of time.
They position your baby in a semi-supine position (45-degree recline angle) to provide good support for your baby's head and neck, but it can affect their breathing if they are seated in it for too long.
If your baby is less than a few months old, try not to let them spend longer than 20 or 30 minutes in their car seat without a break. That’s not only when your baby is in a car, but also if the car seat is attached to a travel system pushchair.
Once your baby is over six months old, this can be extended to two hours. Do not keep your baby in their car seat for longer than two hours at a time and try to have regular 10 or 15-minute breaks if you’re going on a long road trip.
If you're looking for a swivel baby car seat – that's a car seat with a rotating base – you'll be pleased to know there are now more models than ever that have this feature.
Some child car seats have a swivel base to help you put your child into the seat, as you can turn it towards the car's door. Other car seats have a swivel base to make it easier to switch between rearward-facing and forward-facing. The degree of swivel also varies – some can turn 360 degrees, while others turn 180 degrees.
Some car seats have a mechanism to stop the car seat being turned forward-facing too early, but others don't. If there is no way to stop the car seat being turned to face forwards too early, it lost marks in our tests because of the potential for misuse.
Get more advice on buying the right seat by reading our guide to 360 car seats that swivel.
Babies can move up to a forward-facing Group 1 seat when they reach 9kg, but we think this is far too early because their bodies may not be strong enough. It's safer to leave a baby rear-facing until they are at least 13kg or 15 months old, but preferably even longer.
Many parents turn their child forward-facing too soon, risking more severe neck and brain injuries in a crash.
Extended rear-facing car seats, that let you keep your child rear-facing until the age of four/18kg/105cm, are becoming more common, and crash tests show they're much safer.
Find out more about rear-facing baby car seats and extended rear-facing toddler car seats.
Download our checklist to make sure next time you visit a store you're getting asked the right questions.
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Make a note of your child's weight and height, as this will determine what seat you’ll need to buy. Record the weight in imperial and metric units – people often use pounds and ounces, but car seats are approved for weight groups in kilograms. Noting down your child's weight in both units will prevent mistakes when converting from one to another. Measure their height in centimetres.
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+ or i-Size baby 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.
If you're going to have more than one child in your car, you'll need to make sure that multiple seats will safely fit across the rear seat of your car. Most cars can fit two child car seats but, if you've got three children and a small car, you could have issues.
Isofix is designed to make installing your car seat quick and easy, and all new vehicles feature the system. You simply click the Isofix connectors on the base of your seat into the Isofix anchor points in the car.
These anchor points are metal bar connectors built into the chassis of your car. They are often hidden behind the car's seat padding.
Once the Isofix connectors are clicked together, the car seat is secured by a third point – either a support leg that comes built-in into the seat or seat base, or a top tether (a strap that attaches to a mount somewhere behind the rear seat). Both of these work to stop the car seat tipping forward in an accident.
Find out more about the differences between Isofix and i-Size car seats.
Tall passengers in the front, and a car seat in the back generally don't make a good combination. If you've got a car seat with a base that uses a support leg, or an extended rear-facing model, then check that you can still use the front passenger seat, especially if you have a partner who's particularly lofty.
You should never put a rearward-facing baby seat in front of an active passenger airbag and you should make sure the child restraint doesn't rest against the door where side airbags are fitted, or against the airbag panel. You can turn off passenger airbags in some cars.
The car's headrest shouldn't interfere with the child car seat. The head rest shouldn't touch the seat and the car seat should sit flush against the back of the vehicle seat. You may need to pull the car's headrest well out the way, or remove it entirely. If the headrest gets in the way and cannot be removed, you may not be able to use a child car seat in that seat.
Many new cars have buckles quite close to the seat, but older cars often have the buckle on a longer stem. 'Buckle crunch' happens when the length of the stem means that the seatbelt buckle bends around the shell of the car seat when it's fastened. This results in a weak connection and puts pressure on the buckle – it could break or come undone in an accident.
Some seatbelts aren't long enough to go around a rearward-facing infant carrier (Group 0+ car seat). You can sometimes avoid this problem by using Isofix connectors (if your car and seat have them) to attach the seat.
You shouldn't use a base or car seat that has a support leg in a car that has an underfloor storage space in the passenger footwell. The lid of the storage compartment isn't strong enough to withstand the forces that the support leg will put on it in a crash.
Some cars or car seats offer tether strap options as an alternative to a support leg. Top tether straps should only be fixed to a tether anchor point that's been designed to withstand the force of a child car seat pulling away from it in a crash. Headrests are not designed to do this. Some top tether anchor points are unhelpfully placed in the middle of the boot of the car, which can stop you from putting luggage in there.
You need to know whether the cars you most commonly use have Isofix mounts, or whether you'll need a seat that you can fit using the seatbelt. Think about the cars used by grandparents and childminders, and if they will use your seat. Not all car seats fit in all cars.
You can spend as little as £20 on a child car seat, or anywhere up to hundreds of pounds.
Our advice would be not to scrimp on a car seat: get the best you possibly can.
We crash test each car seat we review, and it's very rare that we see a cheap car seat that provides enough protection to become a Best Buy.
Many parents don't want to pay hundreds for a first-stage car seat, but a £300 extended rear-facing Best Buy car seat, that will last until your baby is four years old, works out around 20p a day over the lifetime of the seat.
Group 2/3 seats can be cheaper and, as your child gets older, they can withstand the force of a crash a bit better, so this is where you can save money but still get a decent high-backed booster seat.
Argos, Asda, Halfords, and John Lewis are the some of the most searched-for baby and child car seat retailers at the time of writing. We've included links to these retailers because of their stock availability, best value price or delivery options. Each seller also has a customer score of 70% or more in our best baby and child shop survey.
To see which retailers are rated highly by Which? members, read our expert guide on the best and worst shops.
If possible, try to buy your car seat from a retailer with a fitting service and trained fitters. You may be able to phone up and make an appointment. The other benefit of going in store is that they can sometimes offer a demonstration on their in-store rig. This will allow you to see how to fit and adjust the seat, without the complexities of being in the confined space of a car.
The store should also be able to take the seat out to your car after you've bought it and fit it properly there.
These days, we also recognise that the online market for car seats is enormous and that many parents either can't or don't want to buy a car seat from a retailer with a fitting service when they can potentially get the same seat for a much cheaper price when buying online. This means you'll have to fit the car seat yourself. If this is the case, we recommend the following:
Yes we’d recommend cleaning your car seat as it will become a magnetic for germs. Before you start, read the instruction manual to check how to remove the seat cover, and take photos as you go so you remember how each part of the seat is set up.
The care labels on the cover will explain how it can be washed (machine or hand wash), but the harness usually needs cleaning separately with a brush so you can scrub it.
During our testing, we check how easy car seat covers are to remove, and give them a cleaning star rating, so look out for seats that score well in our reviews.
Second-hand car seats will have wear and tear that could affect the safety protection for your child. The harness, for example, could have been cleaned with harsh chemicals that can make the fabric deteriorate, or the seat could have been involved in a crash and weakened. These are things you can't tell just by looking at the seat, and it's not worth the risk.
Older seats may not comply with the latest safety regulations, or have gone through updated safety tests, or might be missing the instruction booklet that tells you how to install and adjust the seat safely.
Once your child no longer needs their car seat, you may struggle to know what to do with it. Some choose to hold onto it for a second child, others may give to a family member and some might throw it away.
Find out whether you can fix a broken car seat, advice on buying or selling second-hand car seats and how to recycle your old car seat by reading our guide on what to do with an old car seat.