What is i-Size?

What is i-Size?

In a word? The new i-Size European safety regulation applies to children under 15 months and the concept is based on extending the period of rearward facing travel in i-Size seats to 15 months (from 9-12 months previously).

We know that new rules and regulations can be confusing and as the laws are regularly changing there’s a lot to keep up with. The introduction of i-Size has caused much confusion as it is a new regulation running alongside and overlapping with existing regulations. We all want our children to be as safe as possible which is why we’ve put together a simple guide on what i-Size means for you and your little one.


What is i-Size?

Example of an i-Size label which now appears on car seats


What is i-Size?

iSize is a new European safety regulation, which forms a part of a larger piece of legislation referred to as R129. R129 will have three phases: i-Size which was completed and first released in 2013 and two further phases which are still in development but will relate to booster seats and seat-belt fitted restraints. It is hoped that all three phases of R129 will be implemented by 2018, although even at this point there will be an overlap with existing regulations and those such as ECE R44/04 (for seat-belt fixed seats) will continue for some time after 2018.


Why has i-Size been introduced?

The European Commission worked closely with car seat manufacturers and child safety boards to develop the new specifications to help make new car seats meet higher standards and to improve safety for children when travelling in cars.

The new i-Size European safety regulation applies to children under 15 months and the concept is based on extending the period of rearward facing travel in i-Size seats to 15 months (from 9-12 months previously). The reason for the introduction is due to the fact that i-Size car seats provide up to twice as much protection when compared to conventional car seats.

i-Size car seats provide better head and neck protection thanks to the rear facing positioning of the child and are also subject to mandatory side impact testing. All of the studies as part of the regulation used a newly designed crash test dummy which has given a better understanding of protection for children.


i-SIze Logo

i-Size Logo


What does it mean for me?

If you are currently using a conventional car seat which is fixed using a seat belt then there is currently no obligation to upgrade to i-Size. There’s no need to worry or rush out immediately and upgrade but we would say that i-Size is something you should consider when the time comes to buy your next car seat.


Why choose an i-Size seat?

i-Size is proven to be much safer than conventional seat belt fitted car seats for a number of reasons and we think all of these will give parents added peace of mind when travelling with a baby or toddler;


  • Children will have improved head and neck protection

Rear facing car seats offer the maximum possible protection for your child in the event of a head-on collision. In a forward facing car seat, due to the fact that the head is the heaviest part of a child, being thrown forward will cause damage as the neck is not yet strong enough to withstand the force. The new side impact standards also mean better protection laterally.

  • Babies and toddlers are required to travel in rear facing car seats for a longer period

Before July 2013 babies could be moved into the forward facing position from approximately 9 months which we now understand to be too soon. The i-Size regulation makes rear-facing mandatory for at least 15 months (so that neck muscles have developed further and the head weighs less in relation to the rest of the body).

  • All i-Size car seats will have to be used with Isofix which makes correct installation easy

Poorly fitted car seats are a massive problem for the industry and approximately 80% of tested car seats are incorrectly or inadequately fitted. i-Size car seats are much easier to install as they will secure into the Isofix anchor points in the car in a simple ‘click and place’ fitting procedure (no seat belts required) – safer for baby and simpler for you

  • Car seats will be fitted based on the height of your baby and toddler rather than weight

As the seat criteria will be measured on length rather than weight, your growing baby will be able to stay in the seat for longer and this more accurate measurement prevents up-sizing too early


What is i-Size?

Example of an i-Size sticker on a new i-Size compliant car seat


Why doesn’t the new i-Size regulation replace the older ECE R44/04 regulation?

As we mentioned, it is within current car seat laws to still use ECE R44/04 approved car seats. The two regulations, R129/i-Size & ECE R44/04, will run side by side for the foreseeable future due to the fact that i-Size seats will only work with Isofix attachment which is not available in older cars.

This will enable owners of older cars (without Isofix points) to remain within safety regulations using their seatbelt-fixed seats. There will need to be a natural evolution, with all new cars being manufactured with Isofix anchor points and old cars being phased out, before i-Size could completely replace the ECE R44/04 regulations.



Once you get your head round all of the regulations, we think that i-Size is simple to understand and will improve safety whilst also making life easier for parents.  Frustrating car seat installations will be a thing of the past as the new Isofix points make fitting the seats seamless. To have a look at an i-Size seat in use, check out our reviews of the Maxi-Cosi 2wayFamily – the Maxi-Cosi Pebble Plus (for newborns) and Maxi-Cosi 2wayPearl (for toddlers) work with the Maxi-Cosi 2wayFix Base which is a great option if you are looking to upgrade to i-Size.


Maxi-Cosi 2wayPearl

Maxi-Cosi 2wayPearl





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