Car Seat Buying Guide

Rear-facing, forward-facing, high-backed booster seats, oh my! It’s easy to become overwhelmed by the sheer variety of car seats available — not to mention all the jargon: terms like i-Size, R44/04, and ISOFIX are enough to make your head spin.
At PreciousLittleOne, we want to help you get the most peace of mind from your car seat, so we’ve put together this guide with everything you need to know about choosing the right model.
Before we dive in, here are the top three safety tips to keep in mind when choosing a car seat:
1) Car seats are grouped based on your child’s weight or height (not age)
2) All car seats must be rear-facing until your child is over 9kg, or older than 15 months if you’re using an i-Size seat
3) It’s best to keep your child in a rear-facing seat as long as possible

What Car Seat Group Do I Need?

There are currently two types of car seat categories in the UK: R44/04 (which are sold according to weight) and i-Size (which are sold according to height).
To give you a better idea of which car seat group is right for your little one, we’ve put together a handy chart below. Many car seats fall into more than one group and can be adjusted as your child grows.
Group Weight Approx. Age Range Type
Group 0 and 0+ 0-13kg/29lbs Birth to 12-15 months Rear-facing
Group 0+ and 1 0-18kg/40lbs Birth to 4 years Combination rear and forward-facing
Group 1 9-18kg/40lbs 9 months to 4 years Combination rear and forward-facing
Group 1, 2 and 3 9-36kg/20-79lbs 9 months to 12 years (or 135cm tall) Forward-facing, high-backed booster seat
Group 2 and 3 15-36kg/33-79lbs 4 to 12 years (or 135cm tall) High-backed booster seat or booster seat

Group 0 and Group 0+

from birth to 12 – 15 months/0-13kg
Perfect for newborns and designed to see your child through until they are approximately 12 to 15 months old (or 13kg), these baby car seats will keep your little one safe right from the start.
Key uses and benefits:
• All seats in this category are rear-facing, and designed to support the head, neck, and back evenly.
• Many of these car seats are equipped with a handle and come as part of a travel system and can be attached to a pushchair frame.

Group 0+ and Group 1

from birth to 18kg (approx. 4 years)
Car seats in this group will last your baby from birth to approximately 4 years old. They’re designed to adjust as your child grows, and they can be both front and rear-facing, depending on the age of your child. However, it’s best to keep your little one in rear-facing seats for as long as possible (at least until they are 15 months old).
Key uses and benefits:
• Many Group 0+/1 models allow the option to keep your child rear-facing up to 4 years old.
• Unlike a baby car seat, these models will stay in your vehicle and can’t be used to carry your child.
• With both front and rear-facing options, these seats are a versatile and flexible option that will last your child into their toddler years.

Group 1

from 9kg to 18kg (approx. 9 months to 4 years)
Group 1 car seats are the next step up from a baby car seat, ensuring your little one is protected on every journey — including longer trips.
Key uses and benefits:
• Most car seats in this group are forward-facing, but you can find models that offer the option to be rear-facing until your little one is 4.
• Many of these car seats let you choose between either an upright or reclined position.

Group 1/2/3

from 9kg to 36kg (approx. 9 months to 12 years)
Covering three car seat categories and a wide age range, Group 1/2/3 car seats make for a great long-lasting option.
Key uses and benefits:
• They feature a high back and sides, offering extra protection for your child’s chest and head.
• These car seats are outfitted with a five-point safety harness which can then be converted to a high-backed booster seat when your child is older and bigger.
• Designed to easily adapt as your child grows, these car seats will last from 9 months until your child can safely use an adult seatbelt.

Group 2 and Group 3

from 15kg to 36kg (approx. 4 years to 12 years)
Group 2/3 car seats are high-back booster seats. These models don’t have a harness; instead, they can be secured with the car’s seatbelt.
Key uses and benefits:
• They’re typically lightweight and easy to move between vehicles.
• Most models are equipped with added features such as an adjustable headrest and armrests for ultimate comfort.
• These car seats offer added side impact protection.

Group 3

from 22kg to 36kg (approx. 4 years to 12 years)
Backless booster seats, or booster cushions, ensure your child is sitting at the right height so the adult seatbelt can be safely positioned to keep them secure. As outlined by new laws instated in 2017, backless booster seats can only be used by older children weighing more than 22kg and taller than 125cm. (This only applies to newly-approved backless booster seats sold after 9th February 2017.)
Key uses and benefits:
• They’re easy to carry and transfer between cars.
• Backless booster seats can be used as a convenient back-up option when your child’s primary seat is unavailable.

Car Seat FAQs

When should I change baby car seat?

When it comes to changing your child’s car seat, don’t be in too much of a rush. It’s always best to use your current car seat until your child reaches the maximum weight or height listed on the label.

A good indicator it may be time to switch is when the top of your child’s head is level with the top of the seat. That being said, you should always keep an eye on your child’s weight and height to make sure they aren’t outgrowing the seat too quickly.

When should I change from rearward-facing to forward-facing?

One of the most important changes you’ll make is switching from a rearward-facing seat to a forward-facing seat — but it’s also best not to do this too soon.

Weight-based car seats must be rear-facing until your baby weighs 9kg, and i-Size seats keep your child rearward-facing up to at least 15 months. Regardless of which seat you choose, most experts agree that keeping your child rear-facing for longer is the safest option.

As a general rule of thumb, it’s recommended that you leave your child in a rear-facing seat until they’re at least 15 – 24 months old and they’ve reached the maximum weight and height limit for that car seat. This means you may have to switch from using a smaller rear-facing car seat to a bigger rear-facing combination seat that’s suitable for larger children.

Delaying the switch can make a big difference. When you turn your child forward, you expose them to greater danger in the event of an accident. A rear-facing seat, on the other hand, offers better protection to a child’s head, neck, and spine.

What does ISOFIX and i-Size mean?


Designed to provide children with additional protection in the car, i-Size is a European-wide regulation that runs alongside the current UK law (R44/04). i-Size seats are classified based on height (rather than weight) and they keep children rear-facing until they’re at least 15 months old.

i-Size car seats are generally considered safer for several reasons: they ensure children are rear-facing for longer, they provide better side impact protection, and they require the use of ISOFIX fittings (which can reduce the risk of incorrectly installing your seat).

It’s possible that i-Size seats may replace R44/04 in the future, but at this time, it’s up to you to decide which type to buy.


ISOFIX is an internationally recognised system that allows you to fit a car seat into a vehicle without the use of a seat belt. All cars manufactured after 2011 are equipped with ISOFIX fittings, which allow you to “plug in” the corresponding connectors on the base of your car seat. These anchors strongly reduce the risk of misuse and therefore offer a safer alternative to belted installation.

What is the car seat law in the UK?

From the moment your baby leaves the hospital right up until they’re 12 years old (or 135cm tall, whichever comes first), your child is required to travel in a car seat for every journey.

The car seat must meet EU standards, which means it has been certified in accordance with either of the following two regulations:

• ECE R44/04, or
• ECE R129 (also known as i-Size)

Only EU-approved car seats can be used in the UK. Luckily, they’re easy to identify: just look for a label with a capital ‘E’ in a circle.
It’s also important to ensure that you’ve chosen the right car seat based on your child’s size, and that you’ve fitted it correctly according to the manufacturer’s instructions.

Additionally, new stricter rules were instated in 2017 limiting the use of backless booster seats for older children. Under these updated laws, backless booster seats will only be approved for children taller than 125cm and weighing more than 22kg.

For more information, take a look at the GOV.UK website.


About the author: Frances Bishop

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