Buying Guide Car Seats

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 approve


d height-based seats should show “R129” and on approved weight-based seats should show “ECE R44”. Our experts will help you and advise all necessary information that you need to know to find the right product.

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)

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.


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.

i-Size and Isofix

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. But don’t worry, our experts will help you to find what you need and what’s fit to your car.


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