When should your child stop using a booster seat?

Knowing when to graduate your child from their car seat — or booster seat — is crucial in ensuring their safety.

Yet only a small fraction of parents know when they can safely (and legally) graduate their child from a booster seat to a standard ‘adult’ seat in the vehicle.

So what are the rules, and how do you know when it's definitely time for your child to not need a car seat anymore?

Image of seven year old children and their height measured against 145 centimetres

What most people focus on

Current child restraint laws focus on age as the key indicator of when you should move your child out of their car-seat. The barometer is seven years old, meaning that once your child reaches this age, you can legally graduate them from their car-seat to a regular seat in the vehicle. However, new paediatric research suggests parents should actually be using their child’s height as the indicator, rather than their age.

Why height should be the factor

Once you take your child out of their car seat, they’re sitting in a standard seat in the vehicle with an adult seat-belt — which are generally designed to retain a person of at least 145cm.

However, as parents would know, all kids grow at different rates, and children are not all 145cm as soon as they reach seven years of age. In fact, less than three per cent of kids actually reach 145cm by the age of seven. Some children may reach 145cm at age eight or nine, while some might not get there until 10 or 11. This research is what has led to the recommendation that parents use their child’s height as the primary indicator of when to move them out of their car seat, rather than their age.

So how tall should a child be to graduate from a car seat?

The research recommends children to be 145 centimetres tall and pass the ‘Five Step Test’ before they should travel in the backseat of a car without a booster seat. So regardless of their age, they should remain in an Australian-standard approved car seat until they’ve outgrown the size limit.

What's the Five Step Test?

In addition to making sure your child is at least 145cm tall, ensure they can do all of the following — then you’ll know it's definitely safe to graduate them to an adult car seat:

  1. When sitting in an adult car set, can your child sit with their back flat against the seat?
  2. Do their knees bend comfortably over the front of the seat cushion when they’re sitting with their back flat against the seat?
  3. Can they sit with the seatbelt across their mid-shoulder, without it digging into their neck?
  4. Can they sit with the seatbelt low and firm across their hips? Tip: The seatbelt should touch their thighs.
  5. Is this position comfortable enough for them to stay there for the whole car trip?


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