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Things to look for when buying a car seat

The safest way for children to travel in cars is in a new child car seat that is suitable for their weight and height, and is correctly fitted in the car.

The law says that children must use a child car seat until they’re 12 years old or 135cm tall, whichever comes first.

Only EU-approved child car seats can be used in the UK. These have a label showing a capital ‘E’ in a circle.

A properly fitted child car seat will help to prevent your child from being thrown about inside the vehicle, or ejected from it, if there is a crash. It will also absorb some of the impact force, and provide some protection from objects intruding into the passenger compartment.

A seat belt on its own will not properly fit your child, until they are at least 135 cm (4’6″) tall, although it’s better to wait until they are 150 cm (5ft) or taller before moving them to the seat belt on its own.

There are many different types of car seats divided into categories according to the weight of the child. Whilst they broadly correspond to age categories, it is the weight that is most important when choosing the right car seat. There are rearward facing baby seats, forward facing seats, booster seats, booster cushions and Isofix seats.

Height-based car seats are known as ‘i-Size’ seats. They must be rear-facing until your child is over 15 months old.

The importance of rear-facing seats

Your child can legally use a forward-facing car seat when they’re over 15 months old, although it is best to keep your child rear facing for as long as possible. A rear facing seat is recommended until at least four years of age. 

In an accident, a rear-facing car seat reduces impact on a baby or child’s vulnerable head and neck by spreading the force across their whole body.  

 Forward facing seats with harnesses exert more force on a child’s head and neck in the event of a collision.  

 It is recommended to change to a forward-facing seat only when they reach the requirements of a high-backed booster seat, as it is safer to use the adult seat belts rather than a harness once they are forward facing. 

The requirements of a high-backed booster seat are as follows: 

  • The shoulder belt must sit between the neck and shoulder and evenly across the chest and torso 
  • The lap belt must sit across the top of the thighs, not on the stomach 
  • Your child must be able to sit sensibly and not interfere with their seat belt 

Alternatively, your child can use what is known as an extended rearward facing car seat. An extended rearward facing child car seat allows a child to travel rear facing for longer, and generally offer more leg room than standard seats. 

Each seat will have a differing height and weight limit which should be checked before use. You can book an appointment with your health visiting team if you’re unsure of your child’s height and weight. 

This video was not produced by Health for Under 5’s and may contain adverts.

You must check the seat to make sure it’s suitable for the height and weight of your child.

Make sure to remove thick, bulky or slippery clothing such as waterproof coats before putting your child in their car seat. This can lead to your child slipping out of the harness in the event of a collision. 

Checking the harness

Check that the harness of the seat is tight enough to your child’s body on every journey, it should be tight enough that only one or two fingers can fit between your child’s chest and the harness and should not be slipping down the shoulders.  

The harness should be close to the neck and come out in line with the shoulders, it should not be higher than the shoulders or dipping below them. 

Choosing and using child car seats

There are many different types of child car seats available, so take your time when choosing. Visit shops and look around on websites to get a good idea of what seats are available and which ones are likely to be the most suitable for your child and your car.

It is best to take your child and your car with you when choosing your child car seat, and to find a retailer with staff trained in choosing and fitting child car seats. Try to find a retailer who will help you try the seat in your car before you buy it.

Use of second-hand car seats is not recommended as you cannot be certain of the seats history and safety. 

In summary, the child car seat you choose, must:

  • Conform to the United Nations standard, ECE Regulation 44.04 (or R 44.03) or to the new i-size regulation, R129. Look for the ‘E’ mark label on the seat.
  • Be suitable for your child’s weight and height.
  • Be correctly fitted according to the manufacturer’s instructions.
  • Be within date, harnessed car seats typically expire between 5-7 years after being installed but this varies based on the manufacturer, you can find the expiry date under the seat or on the frame 
  • Not be stored in a garage, shed or loft after purchase, as they can become damp or mouldy which affects safety.
  • Be cleaned according to the specific instructions in the manual. 

For a handy checklist to help decide which car seat may be right for your child, head over to ROSPA’s official Car Seats website here. There is also useful advice about replacing a seat after an accident and lots of other useful information.

Fitting a child car seat

You must only use a child car seat if your car’s seat belt has a diagonal strap, unless the car seat is either:

  • specifically designed for use with a lap seat belt
  • fitted using ISOFIX anchor points

You must also:

  • deactivate any front airbags before fitting a rear-facing baby seat in a front seat, the back seats are considered safest, but it is still safe to fit a rear facing seat in the front as long as air bags are disabled.
  • never put a forwardfacing seat in the front due to the dangers posed by the dashboard and airbags.
  • not fit a child car seat in side-facing seats.

Children with disabilities or medical conditions

The same rules apply for children with disabilities or medical conditions, but they can use a disabled person’s seat belt or a child restraint designed for their needs.

A doctor can issue an exemption certificate if a child is unable to use a restraint or seat belt because of their condition.

Guidance for the length of time that children can sit in a car seat

You can seek advice from the child seat manufacturers about the length of time children should spend in their seat, or speak to a medical professional such as your GP who may be able to give specific advice.

It is recommended that you avoid travelling in cars with pre-term and young babies for long distances. Research into the link between car seats and SIDS found young babies may be at risk of breathing difficulties if they travel while sitting in an upright position for too long. You can read more about this on the Lullaby Trust website.

Of course, it’s sensible for you as a driver to take a break after two hours of continuous driving. It will stop you from becoming too tired, and will also give your child a break from the car seat.

There has been research warning of the dangers of carrying children in child seats for long periods of time, but this refers to much longer periods than a car journey, and children who are premature or have a low birth weight.

Even if your baby is asleep, you should take them out of the car seat when you arrive at your destination. Once they’re out of the car seat, transfer them to a firm, flat surface like their Moses basket or cot to continue sleeping. 

Page last reviewed: 01-07-2024

Next review due: 01-07-2027