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Car seat buying guide: How to choose the best one for your baby, toddler and child

We explain the rules and regulations behind a range of carriers so your little one stays safe on the move

Sarah Turner
Monday 26 August 2019 11:15
By law, all children must be in an appropriately sized car seat until they are 135cm (4ft 5in) tall or 12-years-old, whichever comes first
By law, all children must be in an appropriately sized car seat until they are 135cm (4ft 5in) tall or 12-years-old, whichever comes first

Alongside a pushchair and a cot or crib, a car seat is usually one of the first investments soon-to-be parents make. So, where do you start?

Well, unlike most of the decisions you’ll be making where the liberally offered “do whatever works best for you” pearl of parenting wisdom can be reasonably employed, car seats are subject to their own safety laws and guidelines, which change as your baby grows.

This means that “winging it” isn’t really an option and at each stage of your child’s development you will need to have some idea of what you’re looking out for and what legislation needs to be considered.

Car seat law

By law, all children must be in an appropriately sized car seat until they are 135cm (4ft 5in) tall or 12-years-old, whichever comes first.

Children taller than 135cm or over the age of 12 must then wear a seatbelt. In some other European countries, including France and Germany, children must be in a car seat until they are at least 150cm (4ft 11in) tall.

If your child does require a car seat, you can select which seat is appropriate based on their height or weight (see car seat categories below).

Although it’s likely that you will be buying through a reputable brand or stockist who will have done all the safety approval homework for you, there is an easy way to check whether the seat you are buying is EU-approved for use in the UK – just look for a label with a capital “E” in a circle.

In addition to the “E”, the label on approved height-based seats should show “R129” and on approved weight-based seats should show “ECE R44”.

Car seat categories

When browsing online it’s useful to know that car seat group numbers (group 0, group 1 etc.) will also be listed alongside the overall car seat category (forward-facing etc.) The groups are based on weight ranges and may straddle one or more of the seat categories.

This may sound confusing but if you know the age, weight and/or height of your child it is, in fact, fairly straightforward (I promise).

The car seat group numbers are:

  • Group 0: 0-10kg (approx. birth to 6-9 months)
  • Group 0+: 0-13kg (approx. birth to 12-15 months)
  • Group 1: 9-18 kg (approx. 9 months to 4 years)
  • Group 2: 15-25 kg (approx. 4-6 years)
  • Group 3: 22-36 kg (approx. 6-11 years)
Babies must be in rear-facing car seats until they are 15 months old 

Rear-facing car seats

All babies must be rear-facing until they are 15 months old, as before this their necks are not strong enough to withstand the pressure of a head-on collision in the forward-facing position. This is an extension to earlier regulations that advised babies should be rear-facing until they weighed 9kg (approx. 9 months). Groups 0 and 0+ are rear-facing.

Many of these first-size baby seats come as part of a wider travel system alongside a pram, and when used with the correct adapters can be clicked onto the pram chassis. Though this is a handy option, the advice remains that car seats are for travelling and not for prolonged naps – babies should be sleeping in a flat position wherever possible. Check out our pushchairs buying guide for more information.

Forward-facing car seats

Once your child has outgrown the rear-facing seat, the safest option is to use a Group 1 forward-facing seat with an integral harness, which will last them up to the age of four (or until they are around 18 kg). The harness can be adjusted as your child gets bigger and side impact wings provide protection for the head and body.

Combination car seats

Combination seats, also known as extended or multi-group seats, are ones that can be adjusted as your child grows. A one-stop-shop, they cover more than one group, for example – group 1, 2 and 3 seats (which are suitable from 9-36kg, approx. nine months to 12 years). Many have the flexibility of being either forward or rear-facing, or have height-adjustable straps and multiple recline positions.

With the combination option, you must still adhere to the safety guidelines for the weight of your child at any one time (for example, even if a seat has the forward-facing option you’d still need to keep the baby rear-facing until 15 months) and although the initial outlay may be higher, they can prove a good investment if you don’t want to have to keep upsizing.

High-backed booster seat often have adjustable head rests and is the next step up from the forward facing seat 

Booster seats

Booster seats can be either high-backed or backless. High-backed seats are generally the next step on when a child outgrows the group 1 forward-facing seat (at around 15kg, or approx. age four). They still benefit from side wing protection and often have adjustable head rests.

There is usually no integral harness – though just to keep you on your toes there are some high-backed models that do have an integral harness (these usually fall into the combination category, and so are suitable for a wider span of ages).

The high-backed booster seats without an integral harness instead raise the child’s seating position so an ordinary seatbelt can fit safely through slots on the seat. The belt should sit across the pelvis, chest and shoulder, not the stomach and neck.

The guidelines surrounding how long children should stay in a high-backed booster recently changed following concerns over the safety of backless boosters (i.e. the traditional booster cushions) for young children.

Previously, children weighing more than 22kg (typically aged three and over) were okay to use a backless booster but as of March 2017 the recommendation is that children remain in a high-backed seat until they are at least 125cm tall (typically aged seven and over).

Parents who already have a backless booster designed for children smaller than this (the old group 2/3 seats) will not be breaking the law if they continue to use one, but new seats of that specification will no longer be made as manufacturers adhere to the new regulations.

In a nutshell, parents are being encouraged not to rush the transition from high-backed to backless as the latter do not offer as much protection.

What does i-Size and Isofix mean?

i-Size is a new European standard for child car seats that forms part of regulation R129 (i.e. the height-based seats approval system mentioned above). The idea behind i-Size is that children will be seated in an appropriately sized option based on their height, outgrowing it only when they exceed the maximum height listed on the label.

i-Size is currently running in parallel with the old regulation but many new cars are now “i-Size ready”, so it’s worth checking if you have the option to go down the i-Size route.

I-Size seats are only compatible with cars that have Isofix (are you still with me?). Isofix is a car seat safety system that uses fixed anchor points rather than seatbelts to secure car seats in place.

This is generally considered to be a safer method of car seat installation as it makes for a firmer-feeling seat, which attaches to the car with a reassuring click.

Some car seats come with their own Isofix connectors as part of the seat itself and others require the use of an Isofix base to be installed in your car, which you can then click the seat on and off. Not all Isofix seats fit in all Isofix cars (if only life were that simple) but that’s actually something the new i-Size seats aim to rectify – if you have an i-Size-ready car, any i-Size seat should fit.

How much should I spend on a car seat?

That’s a good question, as the price of car seats varies dramatically. The overall range for both the rear-facing and forward-facing options is anywhere between £50 and £250, with the majority coming in at around the £150-£200 mark. Although there is still a range for the high-backed and backless booster seats, they generally become less expensive as your child gets older.

It is worth reading the safety reviews for the seats you are considering as in many cases the cheapest options do not fare as well in crash tests, though this is not always the case. A more expensive model may also come with more accessories, or have a greater longevity across the groups, so it’s not always about that initial price tag.

A mirror allows you to see your baby on the move

What else to consider when buying a car seat

There are several accessories you may want to look into, including a sun shade and a mirror, which allows you to see your baby’s face when they are in the rear-facing position.

And don’t forget to register for the manufacturer’s warranty as soon as you can, as this will ensure you are on the contact list for any safety updates/product recall information.

Why you should never buy a second-hand car seat

Buying pre-loved or second-hand items can save you a fortune but when it comes to car seats, second-hand is generally considered a no-no for the simple reason that you cannot be one hundred per cent certain of that car seat’s history.

Even if there are no obvious signs, it is possible that a second-hand seat may previously have been in a crash and if that is the case, the seat is likely to have been weakened and will therefore be less safe for your baby.

Car seat fitting tips

Car seats should always be placed on the back seats wherever possible as the most common crashes involve impact to the front of the car. If this is not possible, it is vital for rear-facing child car seats that the front passenger airbag is deactivated as the baby’s head in this position would be too close to the airbag if it were triggered.

If you need to transport a child in a forward-facing seat in the front of the car, the recommendation is to move the front seat as far back as possible on its runners to increase the distance between the child and the airbag.

Some retailers, including Halfords and Mothercare, offer to fit the seat for you initially. Whichever way your seat is fitted, it is paramount that you read and follow the manufacturer’s fitting instructions carefully and keep an eye out for signs that the seat is ill-fitted.

Alarm bells should be ringing if the seatbelt is twisted or appears to sit incorrectly across your child, and the harness should be snug. Bulky coats or jumpers should be removed from your child before adjusting the slack.

If you are in any doubt over whether the seat looks secure, try starting again or ask for help. A poorly fitted seat will not do the job it has been designed to do and is therefore not worth the risk.

Sarah Turner is The Unmumsy Mum. Her book is out now

Car seat reviews

Now you know the rules, it's time to pick the right one for you. Start by taking a look at ​our IndyBest buy.

Britax Römer baby-safe i-Size: £190, Britax

The Britax baby-safe2 is a sturdy, affordable seat that conforms to i-Size standards, so is fitted in the rearward facing position and can be used until your baby reaches 13kg or 83cm. Peace of mind safety elements such as “superior side-impact protection”, plus an easy installation, see the baby-safe carrier as a popular pick among new parents – in fact, this was the seat the Duke and Duchess of Cambridge chose to take their three little bundles home from the hospital.

Deep padding makes for a comfy ride and a removable newborn insert means babies are secure from birth. The headrest height can be adjusted with one hand, and we were impressed by the seat’s integral recline: as you alter the headrest, the lying position changes automatically. The seat can be secured by a car’s three-point seat belt but to have the Isofix fitting, you’ll need to buy either of the two compatible bases.

We rate the Britax flex base (£175), as with four adjustable angles it allows the seat into an even flatter recline, offering the most ergonomic travel position for a new baby. Buy the extra adaptors and the baby-safe2 will work with many of the big-brand pushchairs too.

Read our full review of the best car seats to help you make the right choice for your little one.

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