My 3rd child was just born and I've discovered fitting the seats for all my children into the car is a real problem.

My oldest child is using a booster, my middle child a car seat and the new baby is still in an infant carrier.

My car is a large compact (Citroen C3 Picasso), and the 3 seats only physically fit in the car if I use the seat belt (and not the ISOFIX/LATCH system) to secure the car seat - even then the 3 seats completely cover the entire car back seat and there's no way to get to the seat belt for the booster.

I've also tried with my parent's car that is a roomy family car (Hyundai I30 CW) and have the same problem.

We tried putting the baby carrier in the front seat but this didn't work because we need to also fit two adults in the car (and putting the 2nd adult in back between 2 seats isn't practical)

So, what's the standard solution for this problem, how can I get two adults and 3 children into the car safely, reasonably comfortably and legally?

Are there special narrow car seat models? I've seen seat belt extenders on the internet, are they safe? is there anything else I'm missing?

Let's assume I don't have the money to get a bigger car right now.

  • 1
    Britax car seats tend to be skinnier than other ones I have found - try, and you should be able to fit the 3 of them legally and safely in your backseat.
    – Swati
    Commented Jul 30, 2012 at 3:54
  • 10
    Unfortunately very few cars properly fit 3 car seats, and cramming them all in there may actually decrease the safety of the seat. If you do end up putting one in the front seat, make sure you consider the front passenger air bags - they need to be disabled for many car seats or they can cause significant harm.
    – Grant
    Commented Jul 30, 2012 at 14:15
  • 1
    @Swati - you may want to make an answer out of your comment so people can vote on it
    – Nir
    Commented Jul 31, 2012 at 11:22
  • 6
    "So, what's the standard solution for this problem" = In the US, it's called a mini-van. Not the ideal solution for a lot of reasons, but does accomodate the car-seat issue. Regardless, I don't know where you live, but in the US a lot of Fire Departments will do car seat installs/inspections for you. Check with them to see if your car can even handle 3 seats properly.
    – DA01
    Commented Jun 12, 2013 at 6:29
  • 3
    One note here: If you have to put one in the front seat, it should be the oldest child. The baby carrier may never be in the front seat (nor may any other rear-facing carseat); in many areas that is explicitly illegal and it is in any event dangerous. Even with disabled airbags, it is not safe to have a rear-facing carseat in the front seat.
    – Joe
    Commented Feb 2, 2014 at 3:45

11 Answers 11


You can fit 3 RadianRXT car seats side-by-side. It has all the safety features of a Britax and more + things like foldable seat bottoms for travel storage. This saved us from buying a new car ;)

Amazon Link: http://www.amazon.com/Diono-Radian-Convertible-Seat-Shadow/dp/B005MQRAAK


Unfortunately very few cars properly fit 3 car seats, and cramming them all in there may actually decrease the safety of the seat.

If you do end up putting one in the front seat, make sure you consider the front passenger air bags - they need to be disabled for many car seats or they can cause significant harm.

  • 2
    +1 True, few cars can fit 3 car seats (notable exception the Ford C-Max minivan) especially with ISOFIX mounts. Therefore, not using the ISOFIX mounts but "just" the seatbelts might provide just enough flexibility. If not, one of them has to go on the front seat... Commented Aug 8, 2012 at 11:06

I can fit in 2 car seat and an infant carrier in many different cars Opel Agila, Renault Megane, Opel Astra ... using seat belts. It is a hassle, so I start with the middle seat (not the infant carrier) and then add the two on the doors. I have to do it on many cars, because we do car sharing, but it always worked out somehow.


If they are old enough to use a booster seat but you can't fit one in, have a look at seat belt adjusters.

I got an Autosafe one for my youngest and it makes a difference. Admittedly we could always fit three car seats in, but it was a squeeze and we had to move them a bit to buckle all three in.

The adjuster just brings the shoulder part of the belt down to an appropriate level:

enter image description here

Check out the website for more info. Obviously this isn't a suitable alternative for seats for younger kids, as they need the head/neck support as well.

  • 3
    Not relevant for me, booster seats are required by law for children under 8 over here.
    – Nir
    Commented Aug 7, 2012 at 9:11
  • Cool device for the shoulder strap on neck problem but before considering this make sure to check for the lap belt on stomach problem as well.
    – Wayne
    Commented Oct 15, 2014 at 15:41

In the end, after spending hours checking each and every baby-related store in the area I've found a cheap no-name booster that fits between the infant carrier and the children carseat (it's 5cm narrower than every other booster I've seen).

I also had to connect the carseat with the seatbelt and not the ISOFIX hooks for everything to fit in.


Check out Kiddy car seats (www.kiddy.de), they are meant to be buckled in rather than put in a fixed base so they can be shifted around easily, and they have a good safety rating.


If you are in a jurisdiction that doesn't require car seats or booster seats for children 2 years old or older, it might be best just to use a seatbelt. Studies by Steven Levitt have shown that car seats are not as effective as seat belts.

And so, anyway, here I am. It's not a fairy tale. It's a true story about the United States today, and the disease I'm referring to is actually motor vehicle accidents for children. And the free cure is adult seatbelts, and the expensive cure -- the 300-million-dollar-a-year cure -- is child car seats. And what I'd like to talk to you about today is some of the evidence why I believe this to be true: that for children two years old and up, there really is no real benefit -- proven benefit -- of car seats, in spite of the incredible energy that has been devoted toward expanding the laws and making it socially unacceptable to put your children into seatbelts.

  • 2
    Interesting, but irrelevant for me since car seats/booster seats are required by law over here. (I didn't downvote)
    – Nir
    Commented Aug 7, 2012 at 9:13
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    A cursory search shows that Levitt's conclusion isn't necessarily shared by all researchers.
    – DA01
    Commented Jun 12, 2013 at 7:28
  • A seatbelt instead of a child seat? Well, children are fastened into the child seat with a seatbelt, so what is the question here? Anyway, the main benefit of the child seat that it protects against a side impact better, than nothing.
    – karatedog
    Commented Feb 6, 2017 at 12:52

I'm in Australia, and have been researching what to do in this situation for when we have 3 carseats along the back and how to do the seat belts up on the older children. I spoke to a mum the other day about it who has 3 along the back, and she said when she called up Kidsafe (they provide up to date safety information about carseats etc) the lady told her that seatbelt extenders are unsafe, and that she should leave the seat belts done up and the kids just loosen the belts and slide underneath to get into the seats. Then she just adjusts them back accordingly. I hope that helps you.

  • I do this for my kids (my car is a Hyundai i30 CW, I gave a newborn in the safe n sound unity capsule, with two older boys in hipod boston boosters) - I leave the seatbelts buckled and slide them in, then adjust them, but the seatbelts twist all the time, and it is a massive pain to untwist them!! It's been six weeks (since the baby was born) and I'm so sick of it I am looking into buying a bigger car. I was considering seatbelt extenders (which is how I came upon this website!) but too many people are saying they are not meant for this purpose! Oh well :(
    – user6301
    Commented Dec 19, 2013 at 13:05

The mifold (http://mifold.com) is a compact booster seat alternative that also brings the strap down. It's certified in the USA, EU, and Canada and is very affordable.

We use the mifold for several of my kids and relatives and it works great - the only issue is that you do have to put it on a certain way, so it's best used by older kids who know how to make sure they're using it with the strap in the right position. Using that for your oldest should certainly be an option.

Another option, albeit more pricey and intended for those with multiple children (twins/triplets/quadruplets) in the UK is the Multimac https://multimac.co.uk/home - it allows you to fit up to 4 kids across the rear seat.


We have a buick lacrosse and were able to fit 3 car seats across the backseat. Now that our granddaughters are old enough for booster seats, we're having a hassle trying to buckle the seatbelt. Seat belt extenders were recommended but the cars owner manual says not to use them..they're only for adult usage.


I bought a hard cushion cut out of a mattress to use as a booster.

Since his butt is much narrower than the standard booster seat, this made lots of sense.

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