Child car seats: Choosing a child car seat The law on using child car seats

A child dressed up as a policeman

Following the law on child car seats will help to keep your little ones safe

UK law states that you must use an appropriate child restraining system (child car seat) when carrying all children up to 135cm/4ft 5in (approximately 10 years for boys, 12 years for girls).  

However, safety experts recommend that you use a child car seat for all children under 150cm/4ft 11in. This height is the legal requirement in Ireland and also some European countries, such as Germany and France.

For children weighing more than 36kg (5st 10lb) but under 150cm/4ft 11in, our advice is to go by height, not weight. 

Need a car seat? A Best Buy car seat provides good protection from both front and side-impact crashes.

What is an appropriate child restraint?

An appropriate child restraint is one that:

  • conforms to the United Nations standard, ECE Regulation 44/03 or ECE 44/04 (this is marked on a label on the seat), or
  • approved under R129 (also known as i-Size.)
  • is suitable for the child's weight and size, or height (if buying an i-Size seat)
  • is correctly fitted according to the manufacturer's instructions.

Child car seat law by age

Child car seat law by age
Age of childFront seatRear seatWho is responsible?
Child up to three years oldCorrect child restraint must be used.Correct child restraint must be used.

If a restraint is not available in a licensed taxi/private hire vehicle, the child may travel unrestrained.
Child from third birthday up to 135cm in height (approx 4ft 5in), or 12th birthday, whichever they reach firstCorrect child restraint must be used.Where seat belts are fitted, the correct child restraint must be used. The child must use the adult belt if the correct child restraint is not available as follows:

- In a licensed taxi or private hire vehicle
- For a short distance in an unexpected necessity
- Two occupied child restraints prevent the fitting of a third

A child three years old and over may travel unrestrained in the rear seat of a vehicle if seat belts are not fitted in the rear.
Child over 135cm (approx 4ft 5in) in height or 12 or 13 years oldSeat belt must be worn if available.Seat belt must be worn if available.Driver
Passengers aged 14 years old and overSeat belt must be worn if available.Seat belt must be worn if available.Passenger

Height-based or weight-based car seats?

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

Weight-based child car seats:

Most child car seats are split into groups according to the weight of the child they're designed to protect.

These groups are defined by United Nations safety regulations and cover children from birth all the way up to 36kg (about 11.5 years for boys and 11 years for girls).

See our guide to child car seat - car seat weight groups for more information on what seat to buy and when.

Height-based car seats:

i-Size is part of the new European child car seat regulation R129, which came into force in the UK at the beginning of April 2015. 

i-Size car seats go by height instead of weight. You can only use an i-Size car seat if your car has Isofix connectors. 
i-Size car seats will fit all i-Size certified cars and almost all cars with Isofix. Check with your car manufacturer. 

See our guide to i-Size car seats for more information on this new type of child car seat. 

Exceptions to the child car seat law

There are a number of exceptions to the law.

In taxis 

Children under three can travel without a child car seat or seat belt on the back seat. Children over three can travel using an adult seat belt.        

Unexpected but necessary journeys over a short distance

Where an appropriate child car seat is not available, a child over three years old can use the adult seat belt for an unexpected but necessary journey over a short distance. This doesn’t apply to a regular school run or planned journey.

You must not take children under three in a vehicle without a seat belt or the correct child car seat (except in the back seat of a taxi or minicab).

No room for a third child seat in the back

If there’s no room for a third child seat in the back seat (where two occupied child car seats in the rear prevent the fitting of a third child safety seat) a third child under the age of three can’t travel unless they are in the front seat with the correct child seat.

Children over three years can either use the front seat with the correct child seat or sit in the back using an adult belt.

Penalties for ignoring the law on using child car seats

The consequences of ignoring the legal requirements could be expensive (at best) or fatal (at worst). Police are able to administer an on-the-spot fine of £30, or £500 if the case is referred to court. 

Remember, it's the driver of the vehicle's responsibility to ensure all passengers are safely strapped in. If you're the driver, always check. 

More on this...