Child car seats: the law

Using a child car seat or booster seat

Children must normally use a child car seat until they’re 12 years old or 135 centimetres tall, whichever comes first.

Children over 12 or more than 135cm tall must wear a seat belt.

You can choose a child car seat based on your child’s height or weight.

Height-based seats

Height-based seats are known as ‘i-Size’ seats. They must be rear-facing until your child is over 15 months old. Your child can use a forward-facing child car seat when they’re over 15 months old.

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

Only EU-approved height-based child car seats can be used in the UK. These have a label showing a capital ‘E’ in a circle and ‘R129’.

Weight-based seats

The seat your child can use (and the way they must be restrained in it) depends on their weight.

Only EU-approved weight-based child car seats can be used in the UK. These have a label showing a capital ‘E’ in a circle and ‘ECE R44’.

You may be able to choose from more than one type of seat in the group for your child’s weight.

Group Seats‍

Lie-flat or ‘lateral’ baby carrier, rear-facing baby carrier, or rear-facing baby seat using a harness

‍0kg to 13kg‍

Rear-facing baby carrier or rear-facing baby seat using a harness

‍9kg to 18kg‍

Rear- or forward-facing baby seat using a harness or safety shield

‍15kg to 25kg‍

Rear- or forward-facing child car seat (high-backed booster seat or booster cushion) using a seat belt, harness or safety shield

‍22kg to 36kg‍

Rear- or forward-facing child car seat (high-backed booster seat or booster cushion) using a seat belt, harness or safety shield

Manufacturers can now only make booster cushions approved as group 3. This won’t affect any existing booster cushions in group 2 and you’ll still be able to use them.

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 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
• not fit a child car seat in side-facing seats

The Child Car Seats website has information on how to choose a seat and travel safely with children in cars.

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.

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