Confused parents?  What is an i-size car seat?  Back in 2013, a new regulation R129 was introduced, and the first part of this new regulation was i-Size.

i-Size is designed to make car seats easier to choose, fit and use and requires babies to rear face to 15 months.

The video takes a look at why i-Size is different, what the key changes are and if you can safely use your current child seats.

So, What is i-size?

i-size is a new car seat size, it has caused some confusion to parents, so we have shared this video, with the Car Safety Manager at Good Egg Safety Car fitting, who is going to look at and explain what i-size means to you, the parents.

I-size is part of a new legislation, regulation R129.  The key thing about the i-size new legislation that is designed to take away the confusion that surrounds child seats. It makes a child seat easier to fit into the car and easier to use.

The new i-size seats are much easier in several ways as they’re based on your child’s height and stature rather than their weight.  The current car seat regulation is based on a child’s weight and there are several different car seat options and for some there is an overlap in the weight categories.

It’s quite confusing, so i-size takes away that confusion, it’s quite clear that you must use a rear facing car seat up to 15 months, which is clearly labelled, and that’s a legal requirement.  The seats will have height limits as well and on the seat, you can have a look on the bottom of the car seat where it quite clearly states this.  This will make it easy for parents to buy a car seat and still have flexibility on individual style or fitting.

I-size came into force in 2013 but R129 it is being phased in and should be fully implemented by 2018.  However, seats under the R44 regulation can still be used and are still very safe for your child.  They are still legal, there has been a lot of confusion surrounding this topic and people think they must go out and buy a new car seat, you really don’t.Car Seat stciker

You can check the approval sticker on your car seat (often found underneath.) This will tell you the regulation your seat is approved to and its weight and/or height limit.

Most infant carriers are approved to R44 and classed as a group 0+. These seats have a weight limit of 13kg/29lbs. They are also outgrown when the top of your baby’s head is level with the top of the seat.

If you have an infant carrier approved to R129 (i-Size) then it will have a height limit, e.g. 75cm, and possibly a weight limit too. These limits are clearly marked on the seat.

When to change car seat?

The infant carrier is outgrown once your child reaches the height or weight limit, whichever comes first. Don’t worry about long legs over the edge, they are perfectly safe; or that your baby looks “squashed” – think of the car seat as a crash helmet, a tight fit is good.

Summarising i-size

New child seat safety regulation known as Regulation 129 (R129) came into force in July 2013.

  • Better protection for your child
    • Side impact collisions account for around 25% of road accidents in Europe
    • Current regulation (ECE R44) takes no account of side impact protection
    • i-Size specifies that all R129 child car seats must be tested to ensure child remains secure in the event of side impact
  • Key points to consider when buying a new child car seat
  • All child car seats with R129, designed for children younger than 15 months, MUST now be rear facing.
  • All R129 child car seats will now be limited to total combined weight of 33kg (car seat + occupant).
  • All new vehicles will have ‘i-Size-ready’ seating positions. This means that any i-Size child car seat will fit into any i-Size position in a car, regardless of make or design
  • To check whether a car or child car seat conforms to the new regulation, look out for the new i-Size label
    • The new regulation will initially only be applicable to ISOFIX child restraints with an internal harness.
      However, it will eventually apply to all child car seats.
  • Regulation 129 (R129), the new regulation will eventually replace the current regulation (R44), which is to be slowly phased out.
  • Child car seats approved under the old regulation will still be legal for use


    – Make child car seats safer – Easier to buy – Easier to fit – Easier to Use

    I-size Points to remember

Where to next?

For further information on the i-Size regulation and child safety advice

Good Egg Car Safety

Child Seat Safety

Child Accident Prevention Trust