Britax Roundabout G4 Convertible Car Seat, Onyx

Britax Roundabout G4 Convertible Car Seat, Onyx

Choose Only The Best in Safety For Your Child View larger Britax Roundabout Convertible Car Seat The Britax Roundabout convertible car seat is constructed to provide head safety through the use of Britax SafeCell Technology in the base, integrated steel bars, and energy absorbing Versa-Tether that work together to minimize head excursion and reduce the risk of head injury during a frontal impact. The Roundabout also offers a comfortable seat and a secure, adjustable fit with a five-point harness, multiple buckle and recline adjustments, and an infant positioning pillow for extra comfort. Choose Only The Best in Safety For Your Child – BRITAX Offers Head Safety Technologies For Advanced Protection During a car crash, impacts with the front seat aren’t just dangerous – they can be deadly. BRITAX convertible car seats lower your child’s center of gravity to keep them safe, secure and away from front seat. The base of the Roundabout includes SafeCell Technology comprised of SafeCells, an engineered material designed to compress in a crash. This compression lowers the center of gravity to counteract forward rotation of the seat, helping to minimize the risk of head injury during a collision. Located in the sides of the seat shell, integrated steel bars strengthen the connection to the vehicle and prevent forward flexing of the seat during a crash to reduce the risk of head injury. In the event of a sudden stop, the Energy-Absorbing Versa-Tether strap restricts forward movement and reduces crash forces with patented staged-release webbing and a two-point attachment. This webbing securely anchors the top of your child seat to your vehicle in either rear- or forward-facing positions. Tangle-Free Harness And Other Comfort Features The tangle-free, five-point harness allows for multiple height positions and two buckle positions for a snug, comfortable fit as your child grows. High-density comfort foam provides premium comfort, while rear- and forward-facing recline options help your child relax on the journey. You can also use the included infant positioning pillow to optimize fit for small infants. View larger Base With SafeCell Technology Designed to keep your child safe and secure in a crash by compressing and significantly lowering the center of gravity, reducing the forward movement of the car seat. View larger Side Impact Protection System Diverts Crash Forces The Britax Side Impact Protection system includes a rigid shell with deep side walls lined with energy-absorbing EPP foam to contain your child’s head and body and divert crash force energy while creating a barrier against possible intruding objects. This system also protects your child’s head and chest. View larger User-Friendly Features For Easy Installation The Roundabout takes the guesswork out of installation thanks to a range of convenience features. An anti-slip, contoured base grips and protects the vehicle seat, while harness holders prevent straps from getting in the way when you’re putting your child in the seat. Premium lower Latch connectors install quickly and release with a push of a button. For peace of mind, built-in lock-offs provide a secure installation when using the vehicle lap and shoulder belt. View larger Premium Latch Installation Provides an audible click and an easy-pull strap to simplify installation as well as a push-button design for easy removal. View larger Integrated Steel Bars Integrated steel bars strengthen the connection to the vehicle and reduce forward flexing of the child seat during a crash. View larger Energy-Absorbing Versa-Tether Features a staged-release tether webbing to slow the forward movement, reducing the crash forces reaching the child, and a two-point attachment to minimize forward rotation while anchoring the top of the child seat.

Main features

  • Base with safecell technology features safecells designed to compress in a crash
  • Integrated steel bars strengthen the connection to the vehicle
  • Energy absorbing versa tether features a staged release tether webbing to slow the forward movement
  • Premium lower latch connectors for a quick and simple installation featuring a push button for easy release
  • Side impact protection comprised of deep side walls lined with energy absorbing EPP foam distributes crash forces
  • Base with safecell technology features safecells designed to compress in a crash, significantly lowering the center of gravity and counteracting the forward rotation of the child seat which normally propels the child toward the front seat
  • Integrated steel bars strengthen the connection to the vehicle and reduce forward flexing of the child seat during a crash
  • Energy absorbing versa tether features a staged release tether webbing to slow the forward movement, reducing the crash forces reaching the child, and a two point attachment to minimize forward rotation while anchoring the top of the child seat
  • Side impact protection comprised of deep side walls lined with energy absorbing EPP foam distributes crash forces, shields from vehicle intrusion, and contains the head, neck and body

Verified reviews


Easy-to-use, and great for medium-sized babies, but is outgrown WAY too quickly

The Generation 4 Britax Roundabout convertible car seat doesn’t disappoint when it comes to ease of use, but is a major disappointment when it comes to longevity.Like other Britax seats, this seat has safety features that likely do contribute to the safety of the seat (in the US, we don’t know how well seats
• actually
• perform in testing, so we have to trust manufacturers and use common sense). One these safety features is the "SafeCell" technology that is in the base of the seat. It is designed to absorb some of the energy of a crash, and to compress, hopefully reducing forward rotation. A second safety feature is the energy-absorbing foam, designed to absorb some of the energy of a crash, that lines the seat. Another safety feature is the steel bars that line each side of the seat. These bars are designed to strengthen the seat and reduce flexing of the plastic. The Versa-tether is yet another safety feature that can be used for both rear-facing and forward-facing. It too is designed to absorb some force of an accident, and to reduce movement of the seat.This seat comes with "premium" LATCH connectors that are VERY easy to use. The problem with LATCH is that it cannot be used in all seating positions, it often cannot be used in three-across (three seats across the backseat) situations, and cannot be used past a certain limit (vehicle-and-manufacturer-dependent). I personally abhor LATCH, but do appreciate that the style connectors on the Britax G4 Roundabout are MUCH easier to use than are traditional "clip" connectors.The harness on the G4 Roundabout is easy to use, as well. It adjusts very easily, tightens easily, and doesn’t twist any more easily than any other seat.So all of that sounds great, right? Are you wondering why I only gave this seat three stars? Read below!Con #1– The shell of this seat is short compared to many other convertibles on the market. Therefore, this seat is outgrown, especially rear-facing, long before children are ready for the "next step" in seats. The average child will outgrow the Roundabout G4 (rear-facing) between age 2.5-3, which is before children should be turned forward-facing (it is best to rear-face
• as long as possible,
• but hopefully to AT LEAST age 3, preferably 4). Forward-facing, many children will outgrow this seat between ages 3.5-5, which is usually long before they are ready for a booster seat.Con #2– The seat pan of this seat is short compared to many other convertibles on the market. Therefore, rear-facing children’s legs will be against the seat back (which is not a safety issue, but could become a comfort issue as they grow more) before they would in most other seats. Kids like to fold their legs, but this seat
• requires
• it earlier than it would be in most other seats. For forward-facing, the shorter seat pan means that kids’ legs are left dangling without support, which can lead to "pins and needles" feelings in kids’ legs (which they do not like).I would not purchase this seat for an average-sized or a large baby because it will be outgrown way too early. It is probably a great choice for smaller-than-average kids, but not for kids who are any larger.

Terrie Dexter, NY

Fantastic car seat, just as nice as the more expensive Britax models

My wife and I purchased two different Britax convertible car seats for our 10 month old, simultaneously. We purchased aBritax Boulevard 70-G3for the vehicle we will use most, and then purchased this Roundabout G4 to put in the car that we use less frequently, figuring that it was worth buying a second seat to save the hassle of having to constantly remove and reinstall. My apologies in advance for the VERY lengthy review to follow (you can skip to the bottom for my conclusions), but I always try to include as much detail as possible, especially when talking about items involving child safety.Updates from previous “Roundabout 55” model:Britax updated the Roundabout to the new “G4” version (previous version was called the Roundabout 55) in late 2013. I never personally owned the previous version, but based on quick research, the differences on the new version seem relatively minor. The main differences I can see include a new infant insert that is required to be used for children under than 22 pounds, as well as redesigned labels on the seat that make it easier to see instructions for front facing vs rear facing. In addition, they have added labels to the seat that take the guesswork out of figuring out the max shoulder height of children for rear-facing use, so you’ll more easily be able to determine when it’s time to turn the seat around to front facing.Installation:Like my other Britax car seat, I found the Roundabout very simple to install, and it fit fine in the back passenger-side seat of my mid-size sedan (a 2012 Hyundai Sonata). Because my child was 10 months old at the time of the install, we installed it rear facing using the LATCH system. It was very simple to connect and tighten the LATCH connectors, and I had them safely installed in a matter of minutes. Although optional, Britax recommends tethering the seat, even while rear-facing. I spoke to many friends who did not install the tether while the seat was rear-facing, but even if the benefit is only minor, I still felt it was prudent to install the tether. The Britax “versa-tether” was simple to install, and only added an additional 5 minutes to my initial installation. I realize that the tether will be of greater benefit when the seat is front-facing in the future, but I feel safer having installed it now. My total initial installation took me about 10 minutes (though, I had spent roughly 30 minutes the evening before, carefully reading the instruction manual and examining the seat and my cars owner’s manual). I removed and reinstalled the seat again to test how long it would take, in the event I need to remove it for additional passengers in my car. It is very quick to remove (2 minutes), and can easily be reinstalled in another 2 minutes provided it’s going back in the same vehicle and everything is already adjusted. So I am very pleased with this.Real World Use:My son was being moved into this seat from his previous infant seat, a Chicco KeyFit 30. The transition was relatively seamless, which provided us with great peace of mind. My son appears to be very comfortable when sitting in the seat. Because he is only 20 pounds right now, we are still using it with the infant insert as recommended by Britax. It’s a comfortable black fabric pad that sits on the base of the seat, and helps to position him so that the 5 point harness fits him more securely. Britax did a great job with this, and my son seems firmly secured yet still comfortable. The shoulder belts have soft black pads that keep the belt from digging into his neck or shoulders when tightened. The seat has three levels of recline that are very easy to adjust via a lever underneath the front side of the seat. However, per their instructions, the seat needs to be kept in the most reclined (#3) position when the child is rear-facing; I believe it’s somewhere near a 35-40 degree angle of recline. It’s similar to the angle of the Chicco KeyFit seat when installed. I’m sure they have crash tested it and know what is the safest, and my son seems very comfortable at this angle, so no complaints from me.Fabric/Appearance:My main concern in this regard was finding a car seat where the fabric is soft and comfortable enough that it won’t bother or irritate my son, but at the same time be a material that is fairly easy to maintain and clean long-term. Britax has done a great job in this regard as well. It has a comfortable feel to the fabric, but is smooth and firm enough that it is able to easily wipe clean. We have only been using this for a short period of time so far, and only had one incident where it needed to be wiped clean (my son unknowingly had a piece of avocado stuck to his pants from lunch which was smeared and rubbed into the seat fabric). We were able to very easily wipe the fabric clean with a damp cloth and it looks good as new. It can also be completely removed from the seat and thrown in a standard washing machine. I haven’t tried that yet, but will update this review once I do to say how easy and effective it was. As far as the appearance goes, I’m certainly not very picky in this regard. We chose the “Onyx” design, and I think it looks fine. When comparing to the Onyx color of the previous Roundabout 55 version, I think the new design looks a lot more modern. I didn’t factor appearance into my rating, as it wasn’t really a factor in a safety restraint device for me, and is a very subjective topic. To each their own though!Conclusion:In conclusion, rating this five stars felt like an easy decision for me. The Roundabout G4 offered us everything we were looking for in a convertible car seat: it is relatively easy to install, it feels sturdy and safe when installed, our child seems secure and comfortable when riding in it, and it seems like it will be easy to maintain and has a build quality high enough to last for years. It’s every bit as nice as our more expensive Britax Boulevard 70-G3, and with the exception of the HUGS system found on the more expensive Britax models (which is very nice but not a necessity), I don’t feel like anything is sacrificed in this much lower cost seat. The perfect choice for our second vehicle, and it’s nice enough that I would have no problems using it as our main car seat either. I’ll try to update this review periodically if anything changes throughout our use of the seat in coming years. If you have any questions or would like me to address anything else in this review, please let me know in the comments section and I’ll try to update it with the necessary information.

Meagan Quinton, VA


The latch system on this is great. Probably my favorite. The seat is comfortable, and adjusts well. The build quality is excellent, and the ease of cleaning is great, too.I wish they had used the same clips for the tether as they did for the quick releases. That’s my only request.I definitely recommend this seat.

Cornelia Rattan, OK

Britax is the best

I originally owned the Roundabout 50 but had to replace it after a car crash (Thank G-d, no one was hurt!). I loved the roundabout so much and decided to go with the updated version of the roundabout: the roundabout 55. It was easy to install and will last my daughter for a long time. Britax is known to be the safest and it’s also easy to use and comfy.

Nadine Elkhorn, WV

Sturdy, no-frills carseat

We bought this one to use in our second car (we mostly use a Britax Pavilion). The Roundabout is really a basic carseat that gets the job done. I like the Pavilion better, but for the price, this one is really nice. I have generally found the Britax carseats to be well-made, easy to install, and durable. The fit is good (which is important for a carseat) and we will likely get at least 2 years worth of use out of it.

Ruby Dane, WI

Love it!

I bought the Britax Roundabout G4 Convertible Car Seat for our 8 month old son who is getting too tall for his infant car seat. I had asked a friend of mine who works at Babies R Us what is considered the best Convertible Car seat on the market. She told me the Britax brand was by far the best! So, I did a ton of research on the Britax brand before I finalized on the Roundabout G4. I really like the "safety you can see" concept. And the Safe Cell Technology definitely makes me feel confident on my purchase. My son is very comfortable in this car seat. I feel soo safe putting him in this car seat knowing he’s in a top rated car seat for safety and for comfort. I will most definitely buy from Britax again!

Henrietta Pomfret, MD

Great second seat

We bought this to use as a second seat. We have a marathon for daily use and LOVE it. This seat is almost exactly the same minus some nice bells and whistles on the marathon. I did experience the issue of not being able to get the straps up against my daughter, but after doing some research found if you clip the bottom buckle first, then tighten, then do the top buckle it really reduces this issue. I also find the infant insert strange but I am using it since it says it is required for children under 22 lbs. I like that the g4 series has all of the safety information on the side of the seat, because I would have assumed the pillow was just for newborns. One thing I wish Britax had was a ball level like other seats have telling you if you have the correct angle, not just the line— regardless, I will only buy britax carseats with steel reinforcement (note the cheaper version of this seat does NOT have steel) I just think they are superior for safety.This is a great seat, like all britax seats it is easy to tighten straps and buckle in, and it is nice having a second seat that functions just like our primary Marathon. One issue that has bugged me is the pad that goes on the strap for in between her legs keeps coming off… it is just the little things like that that make this the budget option 🙂 People complain about the weight/height limits but my daughter is petite so I know she’ll use this seat for a long time.

Dollie Cannelburg, IN

Easy to install and super comfy

I didn’t think I would notice a huge difference between this seat and my son’s Graco infant and convertible seat (in our other vehicle) but the buckles are nicer (easier to snap into place), the straps adjust easier, the padding is more plush, and my son just overall acts like he likes this seat better than his Graco Nautilus 3-in-1. I was happy with the price too, and after debating for months whether to buy another Graco or to switch to Britax, I’m happy that I went with the Britax and wish all of my sons seats had been Britax. I love the extra safety measures Britax puts into their seats too. Just a well made (in the USA) seat that is affordable, easy to install, and more plush and comfy than the competition. If you’re debating, just go for it. Fits really well rear-facing in my 2007 VW Passat. Two adults can still easily sit in the back seat next to this car seat.

Ann Martin, MI

Safe and mostly comfortable car seat

Fast delivery on 2nd on ordered through AmazonFirst one ordered from private seller on Amazon took almost a month to arrive, I’d recommend getting it straight from Amazon if you have a choiceLove this seat, it’s sturdy and my son appears to be more comfortable now that he’s almost 11 months, then he was in his infant car seat, which was a GracoThe only reason I didn’t give this five stars was that the belt buckle is down in the crotch area and the strap there is not long enough. This causes the shoulder straps to not be as tight as I would like, without pushing against the crotch area too muchThis might not be an issue if I had a daughter, but as you can imagine it’s an issue with a sonOtherwise, it’s a great Car seat and we liked it enough that we bought two. It’s a good trade-off if you’re looking to save a little bit of money and still want to Britax. Not Very many with bells and whistles, but we didn’t need thoseI have read other reviews that complain about the cushioning, saying it’s not enough, I feel compared to other cheaper car seats it seems more than adequate

Camille Pineland, FL

It’s a carseat

It was not the easiest to install and it is hard for me to really tighten it enough. As long as it keeps him safe in the event of a wreck, I am satisfied.

Rocio Sandstone, MN

Great 2nd seat.

We bought this as a second seat. We have a Recaro Proride as our primary. This is cheaper and as others have said, easier to install. The ease of installation was important for the 2nd seat, as it’ll switch cars often by many people.It loses a start for head side support, which our Recaro and the nicer Britax’s have. This helps with napping. Not important for a 2nd seat. It also doesn’t have the recline-ability of our other seat. This is good for optimizing the kid’s position.In sum, good second/short trip seat. You may want head support on your primary seat though. Easier to install than a Recaro Proride is you’re moving it from car to car.

Esther Phenix City, AL

Love it

I have the britax pavilion in my car and my husband picked this one out for his truck. We love them both. My son is 18 months old and fits great in it rear facing.

Rosemary Peoria, IL

Easy to install, safe

We love it and feel that our son is safe in the car with us. He does strain to look around the sides, but I think that is part of the safety feature. It is easy to install and uninstall in our three different kinds of cars.

Tonya Fenton, MO

We like it a lot

We bought this seat for our 9 months old, who was getting to be too big for his infant car seat . We like it a lot. It was easy to install. It is quite comfortable for the baby and has plenty of room to grow. We owned 2 Britax car seats several years ago, when our daughter was a baby.We had no complains then and none so far

Karin Valleyford, WA

This is a great second car seat

This is a great second car seat. Our baby fit in it perfectly. however i can see her out grow it very soon. She is medium height. We love this one because we are bringing it to trips and it’s good for air travel and car travel.

Connie Mattawan, MI

Great for small cars

I have a small mazda 3 and it limited the amount of seats that fits on the car. So I was very pleasantly surprised to find this one. This one is actually my second one, the first is still holding my 3 year old who was too small for a booster seat and I needed a new one for my 1 year old who was too big for a travel car seat.Both kids are comfortable and they are very safe seats. I know britax makes more fancy ones but they would not for my car. My favorite part is the Velcro that holds the straps back which makes it easy to get the kids in the car.

Penelope Axtell, TX