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Baby car seats buyer's guide

Most new parents need a car seat, not least to get their baby home from the hospital. But how do you know which option is right for you and your lifestyle?

By Laura Westerman | Last updated Dec 4, 2023

Baby car seat buyer's guide

Fact-checked by experts from Good Egg Safety. 

How do you know which baby car seat is best for you and your baby and what do you need to consider before buying one?

In this buyer’s guide we’ll explain the different types of car seats that you can use with your newborn and what to look out for before buying one. We’ve consulted parents and spoken to car seat safety experts to put together all the information you need to make the right choice for your family.

Don't have time to read it all?

Jan James, Chief Executive of Good Egg Car Safety, says that the biggest priority when it comes to car seat safety is to make sure your seat fits your baby and any cars it will be used in, and is installed correctly in the vehicle.

This guide covers:

  1. The types of car seats available

  2. What are i-Size car seats?

  3. What are the differences between R44 and R129 (i-Size) car seats

  4. Good Egg Car Safety answers parents' most frequently asked questions

  5. Questions to ask before buying a car seat

  6. Positioning and fitting your car seat

  7. Car seat collision and side-impact testing

  8. Other things to consider before buying a car seat

What types of baby car seats are available?

UK law states that all children need to be in a car seat up to the age of 12 years old or 135cm (whichever comes first). There are a variety of car seats available for newborns. Some parents prefer the convenience of a smaller more portable infant carrier in the first year of their child’s life, others feel investing in a car seat that could last for the first four years, or even 12 years, is the best choice for them.

Broadly speaking, there are two types of seat that can be used with a newborn baby:

1. Infant seats

Infant seats also called Group 0 or 0+ seats are designed to carry babies in the very early months.

Buyers guide infant car seat


  • These seats are smaller and lighter than combination car seats

  • Some of these seats are designed to be attached to a pushchair chassis so that you can take your baby from car to pram without waking them – simply attach the car seat to the travel system (double check that they’re compatible before you buy though) and away you go

  • Have carry handles, which also act as a rebound bar in a front or rear collision, ensuring the seat doesn’t rock

  • May come with a newborn insert to make it a more snug fit for even the tiniest of travellers

  • i-Size and seatbelt models are available


  • You’ll need to check the weight or height limits carefully as a new car seat will need to be purchased after 9-12 months

  • You may have to purchase a base in addition to the infant carrier

2. Combination car seats

Combination car seats also known as Group 0+/1 seat are designed to adapt to your child’s needs as they grow, they can be used from birth to approximately four years old, some are even compatible until 12 years old.

Buyers guide baby car seat


  • Lasts longer than an infant carrier

  • Removable inserts allow the seat to grow with your child

  • i-Size and seatbelt models are available


  • Larger and heavier than infant carriers

  • Designed to stay in one car

  • Some seats are very upright and while approved, are not ideal for a small baby

  • More expensive

What are i-Size car seats?

i-Size seats are car seats that meet the new i-Size (ECE R129) European car seat safety standards that came into force in July 2013. The new regulations aim to increase the safety performance of all child car seats in three ways:

  • R129 (i-Size) regulations have raised the minimum collision testing testing standard. In addition to the front collision and roll-over tests that R44 car seats have to undergo, R129 seats must also be tested in side impact collisions. Testing is carried out using a ‘Q’ dummy which represents the height, not the weight, of the child.

  • There is less margin for error when fitting an i-Size car seat into a car than a traditional seat belted car seat because the seat is attached using ISOFIX points.

  • i-Size car seats are height based rather than weight based, this makes it easier to know when a child needs a bigger seat.

At the moment, both i-Size (R129) and R44 car seats are available to buy and legal to use in the UK, but eventually i-Size will replace R44 and become mandatory in the UK and Europe.

Buyers guide car seat

What is ISOFIX?

ISOFIX is a structural system built into the car that has fitting points to attach an ISOFIX car seat. The seat is latched onto the ISOFIX points and then braced by using either a support leg or top tether.

You can only use an ISOFIX seat in a car with ISOFIX fittings and not all vehicles have them, especially older models. It is important to check the child car seat manufacturer’s compatibility list as there are some vehicle features that can make the child car seat incompatible.

You’ll be able to find out if your car has ISOFIX attachments by looking for tags or labels in the base of the seat or by contacting your manufacturer.

What are the differences between R44 and R129 (i-Size) car seats?

Only UN approved car seats are allowed to be used in the UK. Any car seat you buy must have a label with a capital ‘E’ in a circle and ‘ECE R44’ or ‘R129’. Both R44 and R129 car seats are legal to use in the UK, but there are some differences between the two:


  • Seat classification is based on weight

  • Rear and front impact testing

  • Seat can be fitted using seat belt or ISOFIX points

  • Seat must be rear facing until the child weighs 9kg


  • Seat classification is based on height

  • Rear, front and side-impact testing

  • Seat is attached with ISOFIX points

  • Seat must be rear facing until the child is older than 15 months

FAQ video with Good Egg Car Safety

In this video, Jan James from Good Egg Car Safety answers some of the most frequently asked car seat questions:

  • What is ISOFIX, and is it safer? (00:00:17)

  • How long can a newborn stay in car seat? (00:00:50)

  • When do babies legally go in forward-facing car seats? (00:01:43)

  • How tight should the straps be? (00:02:37)

  • Why buy a £300 car seat when you can get one for £30? (00:03:08)

  • Can I have an infant car seat in the front of a vehicle? (00:04:34)

  • Can I use a second-hand car seat? (00:05:01)

You can read all her answers on the car seat FAQ discussion thread.

Questions to ask before buying a car seat

Not all car seat retailers – even accredited ones – get it right. Nick Lloyd, Acting Head of Road Safety for The Royal Society of the Prevention of Accidents (RoSPA), recommends that, when choosing your baby car seat, you go to a retailer with trained car seat fitters (ideally with car and child, if possible) rather than buying online.

A trained expert will show you how to fit the seat and you should also be able to give it a go yourself, under their guidance. It’s important that every adult using the car seat knows how to use and fit it.

You should challenge anything an expert says that you don’t feel is right – and do make sure they ask you the following:

  1. Your child’s weight – baby car seats have a weight limit

  2. Your child’s height – i-Size car seats have height limits

  3. Your child’s age – this will determine if you need a rear-facing seat (highly likely if your baby is less than 15 months old)

  4. Your vehicle make and model, plus other vehicles the seat might be used in – some seats don't fit some cars and if it doesn't fit, it won't perform as it should

  5. If your vehicle has ISOFIX – only for an ISOFIX car seat

  6. If your vehicle has underfloor storage – some car seats may not be suitable in cars with underfloor storage. Always follow the vehicle and car seat manufacturers' advice

  7. If your seat has a top tether – this is a piece of seat belt material with a hook on the end that is attached to the designated anchor point behind the back seat

Read Good Egg Safety's car seat safety assessment form – this is given to retailers to ensure the right questions are asked.

Positioning and fitting your car seat

How to position your car seat

It is a legal requirement to rear face babies in R129 (i-Size) child seats until they are at least 15 months old. This is because it is much safer for them. Although you can turn them forward-facing in R44 seats a little earlier, child safety experts do not recommend it.

They do, however, recommend that you try to keep your child in a rear-facing position for as long as possible, ideally up to the age of four. Extended rear-facing car seats can help here.

You must always use a car seat if you have a baby in the car with you, even if you’re only driving a short distance.

It is safer to position your child’s car seat in the rear of your car. It is illegal, not to mention extremely unsafe, to fit a rear-facing car seat in the front passenger seat with an active air bag in place.

It’s really important to ensure that your child is in the correct stage of seat for their age, height (R129) or weight (R44). Too small or too big could compromise their safety.

Please don’t be in a rush to move them up until they reach the maximum limit detailed on the side of the seat. It’s best to make the most of each stage so your child has the chance to mature first. Snug is good!

How to make sure your car seat is fitted correctly

You should never modify your car seat to make it fit into your car. Children’s car seats can be fitted using a lap and diagonal seat belt or an ISOFIX fitting. If correctly installed, both are equally safe.

With ISOFIX, however, there is less margin for incorrect seat fitting which is very reassuring for parents and carers. With either method of installation, it is important to check the seat is fitted correctly and securely for every journey.

How to make sure your car seat is fitted correctly

Carrying your newborn car seat

The Professional Network of Pelvic Obstetric and Gynaecological Physiotherapy (POGP) have recently warned that lifting and carrying first-stage baby car seats could be detrimental to postnatal recovery as they aren't well designed for carrying and can be heavy, particularly with a baby inside.

Carrying a car seat during recovery – at a time when lifting should be minimal – could lead to pelvic organ prolapse. As such, it is recommended that car seats aren't removed from the car for at least six to eight weeks after birth.

When it comes to solutions, the POGP suggest carrying your little one to the car in a baby carrier or wheeling your car seat to the car on a lightweight frame. You could also get someone else to lift and fit the car seat for you.

Buyers guide carrying car seats

Car seat collision and side-impact testing

Car seat laws require all car seats to comply with ECE R44/03 or ECE R44/04. You’ll see an ‘E’ label, with a capital E in a circle, on the seat.

This means that every seat is subject to frontal collision testing at a speed of 50km/h. Only rear-facing seats undergo rear impact collision testing at 30km/h.

Seats complying with ECE R44/04 must also go through a rollover test. These tests are carried out using dummies that represent the weight category of the child approved for a particular seat group.

In addition to these tests ECE R129 (i-Size) car seats are also undergo side impact testing.

Claire Waterhouse of Child Seat Safety says that, while under ECE R44/04 there is no requirement to do a side-impact test, some manufacturers do make seats that have this safety feature. You should look for it regardless as well as the seat’s overall crash test rating.

Side-impact protection, to prevent serious head injuries, absorbs the force of the impact in the event of a crash, which means less strain on your newborn’s spine, neck and muscles. This usually takes the form of squidgy padding round the sides and headrest, but some models also have a stabiliser, helping to absorb the force of impact as well.

Under the Road Traffic Act, you can use a seat which has the old standard of R44/03, however these seats will be at least 13 years old and the life span on a seat of this age is only around six years.

Some manufacturers perform more rigorous crash testing on their car seats, details of these crash tests can usually be found on their website.

What else to consider when buying a baby car seat

Make sure the seat is comfortable

While safety should be a first priority, you should also make sure your baby is comfy and snug in their car seat, especially if you plan to go on longer car journeys.

Look for good leg support, a roomy seat and an adjustable headrest. An adjustable headrest is essential for combination car seats (Group 0+/1 here) to ensure the seat is safe and will grow with your child. Most child car seats also have headrests with a set recline to ensure your child’s head remains within the safety of the padded headrest and doesn’t roll forward when they inevitably nod off.

Small babies sitting upright in a car seat shouldn’t stay in the car seat for longer than two hours as breathing could be compromised. For newborns under four weeks old, this should only be for a maximum of 30 minutes.

Is it portable and easy to use?

Is the car seat designed for one car only? Can it be switched between more than one car and it this easy to do? Is it lightweight or heavy and does it have a comfortable handle for carrying?

Check how easy it is to fit in the car, especially if you’ll need to use it in more than one vehicle and assess how easy it is to strap or buckle your little one into the seat. The last thing you’ll want is a fiddly harness that’s tricky to master.

Some models offer a 360-degree swivel function that makes it easier to get your baby in and out of the car seat.

Five-point harness or impact shield?

Five-point harness

The main job of a five-point harness is to protect your child if there is an accident. These harnesses work differently in an impact depending on whether your child is in a rear- or forward-facing seat. A baby should be rear-facing until they are 15 months old.

A traditional five-point harness attaches above each shoulder, on both sides of the waist and between your child’s legs. The harness will restrain them, pushing them back into the seat, spreading the force of the impact through the seat.

Styles vary, with some manufacturers creating automatically adjustable harnesses (when you extend the headrest).

For a harness to be an effective restraint system, it must be buckled correctly – you should only be able to get two fingers between the strap and their collarbone and they mustn’t be able to wriggle their arms out of the harness.

The harness should also be the correct height, sitting as level with the shoulder as possible (although dipping slightly below is fine – unless the seat is forward-facing, in which case it is the opposite).

Impact shield

An impact shield is held in place using the car’s standard three-point seatbelt. The child is restrained in the seat but their arms are less restricted as they are not held down in the same way as in a harness.

In the event of a collision, the child’s body curls over the impact shield, dissipating the forces across the whole of the top of the body and therefore reducing the force taken by the neck and spine.

Seats with impact shields are forward-facing only, so can only be used with children from 9 kg. All seats have pros and cons. Research is important for them all, not just impact shields.

Buyers guide car seat harness

How much should I spend?

Prices for car seats can vary enormously, ranging from £40 to over £400. While all car seats have to pass the minimum safety criteria of regulation R44/04 to be legally sold, many of the bigger brands do their own independent tests at higher speeds.

A lot of the larger car seats that are rear facing-only have passed the Swedish Plus Test, which is the world's strictest car seat test. These tests cost a lot of money, which is reflected in the price of the seats.

Consider your budget and talk to the retailer about the different tests and standards of each seat – they should be able to advise you.

Do car seats expire?

Legally, car seats do not have expiry dates. It is still legal to use seats that were approved to R44/03, some of which date back to the mid '90s.

However, most manufacturers specify a length of time after which their seat should be discarded and there may be separate time limits on using a combination seat with harness and then as a booster. Manufacturing dates can vary from seat to seat, but is usually between five to 10 years from the date of manufacture.

We don’t advise using a seat past its recommended time limit. Your car seat should have a label or a sticker with a manufacturing date. If you can’t find one, check your car seat manual or with the manufacturer for the limit of your seat.

As Margaret Bolt, a qualified Child Seat Safety Adviser and founder of Rear-Facing Toddlers explains, "It isn’t a case that the seat will suddenly become less robust or less likely to withstand an accident, but, as a seat gets older, it becomes more difficult to know its history.

It may have been passed from owner to owner, its crash history might not be known, instructions may be missing or spare parts unavailable.

New seats come out all the time with new safety features, new technology and new innovations. This means that the top-of-the-range seat you bought five years ago may no longer be the safest option on the market." Margaret also advises that, if a new baby comes along, it may be a good idea to consider buying a new seat if your current one is around 10 years old.

Are second-hand car seats safe?

As well as being somewhere for your child to sit while you're driving, a car seat's main job is to protect them. And for that purpose, it tends to be a single use item.

In other words, you can use a car seat until you have an accident, but as soon as that happens the seat has to be thrown away and replaced. Even if the seat looks fine, it may have suffered invisible damage that has made it weak and unsafe, so you can’t risk using it again.

A second-hand car seat isn’t necessarily unsafe though. Using a second-hand car seat that was given to you by a relative or a friend that you know they bought new and haven't had an accident with is fine. But if you buy a seat from someone you don’t know, you have no real way of knowing the seat’s history and you could be putting your child at risk.

Good Egg Safety recommends never buying a second-hand seat, even though it may be a cheaper option, in case there is damage from a previous collision or even from something as simple as being dropped.

Using a car seat on holiday

When it comes to travelling abroad, make sure you understand the law in the country you are travelling to. EU seats can be used throughout Europe, which includes the Middle East, some parts of Africa, Asia and New Zealand.

They are technically illegal to use in the USA, Canada and Australia, although they may be permitted for a holiday.

If a child is under 18kg, then using a car seat on board the plane is the safest option and a few EU seats have TUV approval for use on an aircraft. Check with your airline for their guidelines first.

A car seat can often also be taken in the hold free of charge, but make sure it is well padded and boxed to avoid being damaged.

A final option would be to order a seat from a local retailer at your destination and see if it can be delivered to where you are staying or to the car rental place.

We don’t recommend hiring seats as they are often old, may not be suitable for your child and you won't know the history of them.

How easy is the car seat to clean?

Nothing’s ever squeaky clean when children are involved, so you’ll want a car seat with removable and washable covers that you can easily shove in the washing machine when you need to

Ready to shop? Check out our baby car seat reviews before you buy.

About the author

Laura Westerman is an editor, writer and Deputy Head of Editorial Content at Mumsnet. With over seven years' experience as a full-time editor, five of which have been spent writing, commissioning and editing product reviews and round-ups, Laura has a keen eye for what parents love and likes nothing more than putting together honest reviews to make parents' lives that little bit easier. 

In addition to her work as a writer and editor, she has also appeared in a number of baby product review videos for Mumsnet's YouTube channel. She is mum to a one-year-old.

About Mumsnet Reviews

All Mumsnet product reviews are written by real parents after weeks of research and testing – this includes recommendations from the Mumsnet Talk board. We work hard to provide honest and independent advice you can trust. Sometimes, we earn revenue through affiliate (click-to-buy) links in our articles. However, we never allow this to influence our coverage.

All prices correct at time of publication

Photo credit (images 1 and 2): Good Egg Safety CIC