Guide to i-Size Car Seats

Image for Guide to i-Size Car Seats article

What are i-size cars seats?

I-size, otherwise known as Regulation R129 is a car seat safety legislation that launched in 2013 and is a new way of crash-testing car seats for babies and children. Instead of using a child weight and age to determine a car seat, seats that adhere to the i-size legislation are chosen by the height of the child to ensure the child is the correct size for the seat.

What's different about i-Size seats?

There are some pretty major safety improvements with i-Size regulations. Choosing the best car seat becomes a bit more straightforward as it's measured by height rather than weight, which is a better gauge of how well your child will fit in the seat. Kids can grow at wildly different rates - we've all seen a growth spurt kick in with no warning! Age and weight are still helpful factors, but height makes it easier to see when it's time to move up a seat.

i-Size runs alongside ECE R44.04 (the regulation that governs the car seat groups, which you may have also seen). Although i-Size is the preferred option for many parents, thanks to an easier to understand system, improved safety features and an element of futureproofing, R44 seats aren't expected to be phased out for a few years yet. So, while you may not necessarily need to upgrade your current car seat (provided it meets current regulations) it's worth considering i-Size for the added safety benefits.

Here are the key i-Size car seat benefits:

  • Improved protection for side and front impacts, with a focus on the prevention of head and neck injuries
  • Rearward facing travel (safer for younger children) mandatory up to 15 months
  • All i-Size seats promote and are fully compatible with ISOFIX cars
  • Child height dictates seat choice, not weight
Shop all car seats

What is ISOFIX?

ISOFIX car seats attach directly to the chassis of the car, rather than using a seatbelt. Isofix metal arms attach and lock on to a U-Bolt-Like piece of metal at the back of the vehicles seat. This means that the car seat remains in place, and does not rely on the childs weight to keep the seat in situ. All i-Size car seats are ISOFIX compatible, so if you have an ISOFIX compatible car, you'll be able to attach your new i-Size car seat more securely. Learn more about ISOFIX in our handy ISOFIX guide.

Why is a rearward facing car seat better?

Before your baby is 15 months old, its neck simply isn't developed enough to withstand force from collisions - which can lead to serious and often life-threatening injuries. Rearward facing car seats have been proven to be 5 times safer than forward facing as they restrain the head and spread the impact, rather than throwing the head forward.

i-Size Car seat sizing and fitting at Halfords

Along with a fantastic range of i-Size car seats, Halfords have trained fitters who can show you how to fit your car seat for free*. Pop into your local branch where our fitters will be happy to help you, so you'll be on the road with your little one in no time.

*Service not available on seats purchased from Halfords Approved Partners.

If you aren't sure which child car seat to go for, or would like to compare different makes and models, then start with our car seat buyer's guide, or ask one of our colleagues in-store.

Shop all car seats