What do Group 0+, 1, 2, 3 car seats mean?
- Mar 25
- 2 min read
If you’ve ever looked at a car seat and seen labels like Group 0+, 1, 2 or 3, you’re not alone in wondering what on earth they mean.
These groups come from an older regulation called R44, which classified car seats based on a child’s weight.
Today, many seats use a newer system - so let’s break down what the old groups meant, and what’s replaced them.
The old system: R44 weight-based groups
Under R44, car seats were divided into groups based on how much a child weighs:
Group 0+: birth to 13kg (around 12–15 months)
Group 1: 9–18kg (around 9 months to 4 years)
Group 2: 15–25kg (around 4 to 6 years)
Group 3: 22–36kg (around 6 to 12 years)
You might also see combination seats, like:
Group 0+/1
Group 1/2/3
These cover multiple stages in one seat.
What was the issue with groups?
While the group system was widely used, it had some limitations:
It relied on weight, not height
It didn’t always reflect how a seat actually fits a child
For example, two children of the same weight can have very different heights and proportions.
The newer system: R129 (height and weight-based)
Car seats are now increasingly approved under R129.
Instead of weight groups, R129 uses height and weight (cm and kg).
So instead of “Group 1”, you might see:
61–105cm rear-facing seat
100–150cm high-back booster
This makes it clearer how long a seat is likely to fit your child.
Is i-Size the same as R129?
Not quite.
R129 is the regulation
i-Size is a specific category within it
i-Size seats meet additional criteria, including:
ISOFIX installation
Specific size compatibility standards
But many R129 seats are not labelled as i-Size - and that’s completely normal.
Can I still use a Group 0+/1/2/3 seat?
Yes. R44 seats are still legal to use if you already have them and they fit your child.
However:
Newer designs are now based on R129
R44 seats are no longer being manufactured and are being phased out of the market
What does this mean for parents?
The biggest shift is this:
We’re moving from “what do they weigh?” to “what’s their weight and height?”
This helps encourage:
Better rear-facing use
More appropriate transitions between stages
Clearer guidance for parents
FAQs
Do I need to replace my R44 seat?
No - if it fits your child, is within its lifespan, and hasn’t been in a crash, it can still be used.
Is R129 safer than R44?
R129 includes updated testing (including side impact), but correct use and fit are still the most important factors.
Why do some seats still mention groups?
Some retailers and brands still reference groups because many parents recognise them, especially during the transition between systems.
