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European Standards vs American Standards: Car Seat Edition

There are a few main differences between European car seats and American car seats, one of the most obvious being the European adoption of the ISOfix. This was recommended by the United Nations and utilized by the European Nations in the mid 1990s. The US National Highway Traffic Safety Administration (NHTSA) opted not to utilize this system, focusing more solely on the LATCH system because “there is likelihood that the support leg would be misused if the installation requires further action from the parent.”[1]

The UK Britax MAX-WAY (Convertible: 9m-6y: ~20-55lbs)

The UK Britax MAX-WAY (Convertible: 9m-6y: ~20-55lbs)

There are two ISOfix standards because it is taking so long for both car seat and car manufacturers to develop and agree on the new standards. There’s the “Universal” and the “Semi-Universal” (or “Vehicle Specific” — this is where the load leg comes in). It was introduced in 1997, became standard in 2004, and by June of 2006 all car seats had to meet this standard. As of February 2011, it is required by law that the system must be integrated into all new cars.

Universal ISOfix requires three anchorage points: two latches in the back and a top tether to stop the seat from projecting forward in a crash.

The Semi-Universal ISOfix requires the two latches in the back and then a third anchor point that is not a top tether. This is where the “support leg” comes in. This support leg essentially does what the top tether does; it matters more of what your car can take. There is a debate on which is a safer feature, but they do the same job, and neither side has come to any real conclusion.

Generally, you buy the base separately from the car seat in Europe. Using Britax as an example: they sell two infant car seat bases. There’s the BABY-SAFE ISOfix Base and the BABY-SAFE Belted Base. Both have the support leg as the third anchor option.

So in a nutshell: European Standards = LATCH system OR seat belt system + one other anchor point (either top tether or load leg)

American infant car seats cannot be used in Europe as they generally do not have a third anchor.

More Key Differences:

If using the seat belt for installation (and not the ISOfix system), the correct routing for forward facing must clearly be marked in RED and rear facing must be marked in BLUE.

The buckle on the seat must be operational by a single button or similar device. It must only lock when all pieces are in it. The button also has to be red and no other part of the buckle can be in this color (and is typically a lighter color, like grey or white). This makes it easier in case of an emergency. This means there are NO CHEST CLIPS. Chest clips are a very controversial “safety” feature in American and Canadian car seats. This will give you a brief insight on why people do not like chest clips.

I would like to note that there are fewer convertible Britax car seats in Britain than there are in the US. They also have a higher starting weight and lower ending weight than ours.

Cybex Aton 2 for the UK.

Cybex Aton 2 for the UK.

Cybex Aton 2 for the US.

Cybex Aton 2 for the US.

Note the differences between the belts on the two Cybex Aton seats shown on the left. They are the exact same car seat, with a few key differences that make their origin easily identifiable.

Impact Tests:


  • Frontal Impact: The car seat is loaded into a “vehicle” and thrust into 15,400+ pounds of reinforced concrete at 31 mph.
  • Rear Impact: A 8ft by 2.5ft rigid steel impactor is thrust into the back of the “vehicle” at 20 mph.
  • Overturning: The “vehicle” is rotated 2-5 degrees per second. When upside down, the head should not move more than 12 inches from its original position.
  • Seat Belt: The seat belt must be buckled and unbuckled 5,000 times after impact testing to ensure that it still works.

According the Evenflo website, a US company, “(US) Car seat safety standards require a frontal impact test with a 30 mph velocity change. This approximates the crash forces generated in a collision between a vehicle traveling 60 mph and a parked car of similar mass, or the energy produced in a fall from a three story building. There are currently no provisions in the U.S. and Canadian standards for side impact testing. The U.S. National Highway Traffic Safety Administration (NHTSA) is in the early stages of developing a child side impact test standard.”[3]

During my research, I discovered that neither Europe or the US have side impact testing, but I did discover that the US does not require test results to be posted. Manufacturers may post their results if they choose to, but it is not required by law. The car seats either pass or they don’t, and it’s up to the manufacturer to prove just how safe their car seat is compared to the others.

Check out our video roundup of the best Infant Car Seats of 2017!

Chelsea is a recent transplant to Boston and an up-and-coming car seat expert at our Brookline store.

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  1. Can European cars eats be used in the us? And would you say one is safer then the other?

  2. Hi Chelsea!

    I live in Sweden and I’ve got a 2 year old and another one on the way in september. I didn’t actually know that you there where two different ISOfix standards. So, does that mean that my European seat doesn’t work on cars prior 2011 in the USA?

    I get the part about american seats going to Europe, but what about the other way around?

  3. This is a tough question! I asked our buyer to weigh in, and she said the following:

    I would say that it really depends on the seat and the car. If your seat has a load leg, you can use that here without a problem. If your seat has a lower tether, it is probably fine to use it without that, but it is always important to read the owner’s manual.

    The safety standards are higher in Europe than in the US, so European seats are generally fine in the US.

    I hope this helps!

  4. Hi! Thank you for this information. 🙂
    The new “I-Size” regulation is about to hit Europe and with it a new standard of safety is set for car seats. 🙂
    This will work side by side with our current ECE 44/04 for quite a few years, but all new seats made after the I-Size goes global will be made with the I-Size and any new vehicle will also be I-Size. 🙂

    You can read more about all this here:

    Thank you for spreading the word, and let’s all work together to keep our children safe in cars! 🙂

  5. Hi Chellsea
    What is the best car seat I can buy for the newborn so it can be used in Europe and US – my kids are relocating to Europe in 2 month after baby birth.
    Thank you

  6. Is there a car seat I can buy that will work in Europe and the US for my 9 month old daughter? We will be moving to England in about 9 months but will be in the US until then? We are going to need to switch her out of her infant seat very soon.


  7. In the US some individual companies have side impact testing ie. Doral. In Europe the ADAC does extensive side impact testing. Although not required in Europe or the US, side impact testing is done.

  8. Dear Chelsea,

    First, thank you for your article.
    Then, would it be possible for you to say if we would use our Cybex Sirona car seat in the US? Indeed, we bought it 3 months ago for our son who is now 8 months and we are moving to the US this summer…

    Thank you for your help!

  9. Hi Sandrine! Unfortunately, that seat isn’t sold to the US so we don’t have good info about it – but you can contact Cybex to find out. Try this page for answers:

    …and let us know what you find out. Good luck!

  10. You can’t use a European car seat in the US because they don’t have chest clips and it is required to have chest clips on US car seat. +now all US car seat have latch systems and top anchors which makes them safer .

  11. Europe now requires a side crash test with the i-size norm. 🙂

  12. Hi Chelsea,
    thanks for your article, I’m still a bit confused and wondering if you can help out. We are travelling with children to Europe in 2015, we are hiring a car and are looking at car seats. We have a 5 year old and 2, 3 year olds all will be over 15kg by the trip so will likely to be in booster seats, will these seats have anchor points? We plan to purchase these when we arrive in Rome.

    Your help would be much appreciated.



  13. Hi Sharon!
    We’re not really familiar with European cars, so you’ll need to do some research on the specific car to determine whether they have anchor points suitable for your seats. If it helps at all in your research, in the EU the LATCH system is known as ISOFIX, so you’ll want to look for that.

  14. Hi Chelsea,
    Can I just ask you to clarify that the US version of the Cybex Aton 2 can legally be used in the UK as we are soon to be new parents living in the States but will be visiting family in the UK and possibly relocating back to the UK in the next 6 months. We really don’t want to have to buy two infant seats! Thanks!

  15. Cathy,

    You should check this with Cybex customer service – check out this page!

  16. Unfortunately, any seat that doesn’t pass US FMVSS 213 standards can not be used by residents of the US. That would include all European seats. All seats used by US residents must have the sticker saying it is FMVSS 213 certified to be legal to use in the US. Non-residents are allowed to use seats that are certified in their home country during visits.

    In Europe, only seats that meet the ECE 44/ 04 or i-size requirements can be used by both residents and visitors. Therefore, US seats, even with an equivalent counterpart in Europe, such as the aton2, would be illegal to use by a European resident or visitor. If you’re in Europe, you need a European seat.

  17. I have just returned to Canada from the UK and was shocked to see that the Britax seats in the UK, do not have the chest buckle ! The shoulder straps therefore do not remain on the shoulders and the 2 and 3 yr olds easily unbuckled themselves, why the difference ? Thanks

  18. I am totally shocked that they do not require a chest buckle in European car seats! I understand the whole way of securing the car seat to the car and all that. However what is securingvthe CHILD to the seat? Those straps are so far apart and in a fast crash or even a slpwbone a child’s entire chest could fly forward. I am so surprised by this. Wow….

  19. ^^ My name is Miranda and I apologize for the typos above! Thank You!

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