Purchasing a new vehicle: will my car seats fit?

Shopping for a new car is stressful enough, but if you’re planning to keep your existing child seats, there’s an extra layer of homework involved. Not all vehicles are created equal when it comes to car seat compatibility – even cars that look identical in size can behave very differently once you try to install seats in them.

The best thing you can do? Take your seats with you when viewing cars. Install them fully, not just place them on the seats, and check for proper stability, space, and usability before you commit. Here’s what to look out for.

Install your seats properly, not loosely

A seat that looks like it fits doesn’t always work once you’ve done a proper installation. Try every seat you plan to use, fit it as you normally would, and check movement at the belt path or ISOFIX connectors. A seemingly perfect fit can become unusable once tightened.

Planning three-across? Test the full lineup

Even a few millimetres can be the difference between a safe installation and something that simply won’t work. Line up all your seats together exactly as you would in daily use. Some combinations work in one car but not another, even within the same model range.

Don’t forget adult comfort

Hop into the front seats with the child seats installed in the back. Can the driver still sit safely and comfortably? Can a taller passenger fit? A seat that requires the front seat to be pushed too far forward may be unsafe in real daily use.

Check tethering access and front-seat rails

Look under the front seats for exposed rails or tether points. Are they easy to reach without contorting your hands? Does using them restrict the amount of movement the front seats have?

Inspect the ISOFIX

Some ISOFIX points sit higher or deeper than expected. Once you’ve installed your base or seat, does it sit flush? Is there less than 1 inch of movement? Does the support leg make stable, full contact with the floor?

Underfloor storage boxes

These can interfere with support legs. Find out whether the boxes are reinforced or whether the vehicle requires manufacturer-approved inserts or fillers. Never assume they’re safe to use without them.

Check the seatbelt length

Some belted seats – especially infant carriers, Joie Stages-type seats, or Graco Slimfit R129 – require longer belts. Make sure the belt reaches comfortably and can be routed correctly without stretching at odd angles.

Seatbelt compatibility

Check both ends of the belt:

• Is the buckle recessed or on a floppy strap that might cause buckle crunch?

• Is the male end too bulky to thread through the belt path?

These little details can make or break compatibility.

Centre seatbelts

If the centre belt comes from the ceiling, check that it retracts correctly and sits in the right position for the seat you’re using. If planning a high back booster there, is there forward anchorage to keep the seat stable?

Headrests

High back boosters often need the headrest removed or turned. Some cars don’t allow this. For rear-facing seats, make sure the headrest can support a mirror safely if you use one.

Read the vehicle manual

Some cars restrict:

• support leg use

• child seats in the front

• child seats in the centre

• use of boot seats

Always check what the manufacturer permits.

Watch the seat angles

Vehicle seats that appear flat can be surprisingly sloped. Once your car seat is installed, it may sit too upright for a younger child or newborn. A quick installation test will reveal this.

Considering third-row seats?

If your car has boot seats:

• Are child seats allowed there?

• Will boosters retract and anchor properly?

• If you need to access the third row in an emergency, can a middle-row seat still fold with two seats installed?

These practical things matter far more than theoretical seating capacity.

Boot space and pram fit

Bring your pram, pop it in the boot, and see what room is left. A car can look deceptively spacious from the outside but have a surprisingly shallow or narrow boot opening.

Airbags

If you ever need to use the front seat for a rear-facing seat, can the airbag be deactivated? This is crucial for future flexibility.

Think Ahead: Future-Proof Your Choice

Just because your current seats fit doesn’t mean your next ones will. Extended rear-facing seats to 125cm/36kg or tall high back boosters can take up more room than you might expect. If your child is nearing the point of leaving car seats completely, consider whether they’ll be able to sit safely with full belt contact as a growing pre-teen or teen. The car that works brilliantly for your toddler today might not work for your 13-year-old in a few years’ time.