Britax Poplar Narrow Convertible Car Seat - Stone Onyx

Style:Stone Onyx
Britax Poplar Narrow Convertible Car Seat - Stone Onyx
Britax Poplar Narrow Convertible Car Seat -  Magenta Onyx
Britax Poplar Narrow Convertible Car Seat - Cobalt Onyx
Ships FreeShips Free
In Stock
Add Accessories:
Britax Car Seat Travel Cart
FORM vwitem =1
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:37
Britax Car Seat Travel Bag
FORM vwitem =2
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:19
Britax View-N-Go Back Seat Organizer
FORM vwitem =3
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:3
Britax EZ-Cling Sun Shade (2 Pack)
FORM vwitem =4
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:6
Britax Seat Saver Waterproof Liner
FORM vwitem =5
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:12
Britax Kick Mat (2 Pack)
FORM vwitem =6
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:13
Britax Back Seat Vehicle Mirror
FORM vwitem =7
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:13
Britax Head & Body Support Pillow
FORM vwitem =8
Sales Rank =
Inventory isAvailable:1
Inventory qtyInStock:17

Ready to go with room to grow! The Britax Poplar Convertible Car Seat takes the stress out of moving to the next car seat stage thanks to the patented ClickTight® Installation and slim SpaceSaver™ design. This car seat accommodates up to 50 pounds rear facing to help keep your child riding safely even longer and easily switches to a forward facing car seat as your child grows. ClickTight Technology installation provides fully open seat belt paths that are clearly labeled and easy to access, and the automatic tensioner takes care of the tightening. Slim outside and spacious inside, the toddler car seat features 17" SpaceSaver technology designed to fit 3-across* without compromising on trusted Britax safety and premium comfort. The Britax car seat boasts a patented SafeCell® crumple zone and V-shaped top tether to help manage crash energy. The reinforced frame and belt paths provide strength and stability. Rear facing car seat cover fabrics are naturally flame retardant with no added FR chemicals and safe to machine wash and dry. *Britax cannot guarantee 3-across installation fitment in all vehicles

Recommendation – Britax strongly recommends:

  • Children ride rear-facing to the highest weight or height specified
  • Children should remain in a child seat with a 5-point harness until reaching the maximum weight or height allowed
  • The top tether be used at ALL times when installing the child restraint forward-facing.

Why You'll Love it

ClickTight Installation

Install with confidence in three easy steps: open, thread & buckle, click it closed

SpaceSaver Design

Slim outside, spacious inside: 17” seat design without compromising on trusted Britax safety & premium comfort

Extended Rear-Facing

Fits up to 50 lbs and 49" to help keep your growing child riding rear-facing longer


14-Position, Quick-Adjust Headrest & Harness

Create the proper fit as your child grows

Patented V-Shaped Tether

Staged-release stitches help slow & reduce forward movement during a crash

Dishwasher Safe Cup Holders

Removable for easy cleaning between car rides

6-Position, Quick-Adjust Recline

Helps you find the most comfortable fit for your child & the best fit for your vehicle

SafeCell Technology

Acts as a crumple zone, helping to keep crash energy away from your child

5-Point Safety Harness

Helps evenly distribute crash energy to keep your child safe

Naturally Flame-Retardant Fabrics

With no added FR chemicals

Carbon Steel Frame

Reinforces the seat structure to help keep it sturdy and stabilized


  • Product Dimensions: 20.5" x 17" x 23.5"
  • Harness Slot Heights: 8", 8.7", 9.4", 10.1", 10.8", 11.5", 12.2", 12.9", 13.6", 14.3", 15", 15.7", 16.4", 17"
  • Buckle Strap Depths: 4" - 7"
  • Child Weight: 5-65 lbs
  • Rear-facing Harnessed Height: Less than 49"
  • Forward-facing Harnessed Height: Less than 49"
  • Rear-facing Harnessed Weight: 5-50 lbs
  • Forward-facing Harnessed Weight: 22-65 lbs
  • Seat Area Depth/Width: 11" / 12"
  • Shoulder Width: 14"
Product Reviews
out of 5.0
17 Reviews
Ratings Snapshot
of Reviewers
Mounds View, MN
Verified Buyer
Best in class slim car seat
May 5, 2024
Extremely comfortable, slim, and compact! I needed a car seat that was compact enough to RF in the third row of my SUV and decided to buy to see if this was more compact than our E2F, it is! It has such comfortable and soft padding and it was an absolute dream it install It’s as simple as buckling a seatbelt and pressing down on a door. Would recommend this seat to anyone.
  • compact, comfortable, slim, easy installation.
jeonhwa K.
Verified Buyer
May 1, 2024
Convenient to use. It's safe.
Verified Buyer
Bought for grandkids
March 21, 2024
Easy to install
  • Easy to install
  • Wish it had rebound bar
Verified Buyer
Spacious for a 17" seat
March 19, 2024
I was VERY surprised with how spacious the seat is for my 5yo with it being a 17" seat. The harness strap tightens and loosens like butter; however, Britax is sending me a new seat due the the straps slightly loosening over time (about 1/2" while driving). I am hoping that the new seat is just as easy to tighten. I'm overall impressed with the quality and really only have one complaint. I just wish they would've put the recline lever on the side with numbers like the One4Life instead of at the front of the seat. Install is so much harder having to move the seat to adjust and then not know how much I have adjusted it since there is no indicator.
Southern California
Verified Buyer
Affordable, Narrow, Easy to Install Perfect Car Seat
February 25, 2024
We have loved Britax for many years however had to switch to a different brand when I needed to fit 3 across in the back of a Tesla Model 3. Unfortunately, I just never could get a good install with another brand specializing in narrow car seats. I am so incredibly happy Britax came out with a new car seat. With 3, soon to be 4 kids in car seats, it is very important to me that we have safe, easy to install seats. I just bought 3 of these seats for the Tesla and tempted to buy more to replace my current seats in our SUV. Easy to install securely and very narrow for a full feature Britax seat. I am a veteran mom and cannot express how excited Britax releasing these seats made me. We have owned 10+ car seats over the years as I do not like moving seats between cars and grandparents cars --- this Poplar is by far my favorite; even compared to other seats I have that cost nearly twice as much!
  • narrow, easy install, inexpensive
Verified Buyer
Car Seat for our 1 year old
February 20, 2024
We recently purchased the Britax Poplar for our one year old. We have a mid size 3 row SUV and it fits perfectly in the middle row. It takes up less room than her infant seat and my husband is able to move the driver's seat back more than he was before.
The seat itself is heavy and sturdy. It is pretty easy to install, as well.The cushions are really comfortable. My daughter can easily fall asleep in it. We use it rear facing. Definitely recommend, especially if you are looking for a safe and compact 3 in 1 car seat.
  • We like everything about it!
  • No cons as far as I can tell after 2 months of use.
Seattle, WA
Verified Buyer
Fits perfectly
February 7, 2024
Definitely not as bulky as the standard Britax convertible, shoulder strap pads have a grip to prevent slipping, the new “click tight” button is easier to use and hidden under the padding, which protects it from debris (food particles). Fits very well in a large SUV and truck. Only flaw I have noticed is that the child’s bottom sits very deep in the seat when you do not use the extra provided padding, which is not to be used after a certain weight.
Georgetown, Indiana
Verified Buyer
The perfect seat
January 28, 2024
The perfect narrow seat! It feels safe and secure and fits three across!
Verified Buyer
Easy to use narrow seat
January 20, 2024
We purchased this seat because we really like our Britax One4Life convertible seat, but find it very bulky. The Poplar is super easy to install thanks to the Britax ClickTight system, which is critical because we have to move our car seats around frequently. It is compact front to back when rear facing and narrow enough to fit three across with a Graco infant seat and adult in the back seat of our 2019 Toyota RAV4. The fabrics are cushy and easy to clean. We have no complaints after two months of use.
  • Compact, narrow
  • The ClickTight takes noticeably more force to close on this seat than our One4Life
Hampton, VA
Verified Buyer
Great Compact Seat
January 17, 2024
We love this seat! It’s super compact both front to back and side to side, but allows the child a good amount of space inside of the seat. My toddler hated sitting in the Rava but loves this seat. Install is super quick and easy, I love that you can have cup holders or not. We now have them in both cars for both children
Verified Buyer
Narrow frame
January 16, 2024
Easy to install and narrow frame allows for all the children to sit in the back seat. Would recommend especially if you have multiple car seats.
  • Britax quality, easy to install, frame
Verified Buyer
Pretty and easy to install
January 9, 2024
I just installed the car seat about a week ago but I am already impressed. I love the Clicktight installation. The blue is so pretty too. My 9 month old likes his car seat and is very happy to be out of the infant seat.
  • Clicktight
Verified Buyer
January 2, 2024
I love this car seat so much! I needed to fit 3 across or 2 together in my Expedition. This fits so well! I wish this was available when I was shopping for the other car seats a year ago. The installation is the easiest of any car seat I’ve owned so far!
  • Narrow, easy install, narrow front to back.
Best Uses
  • Extended rear facing. 3 across and 2 together.
  • Under 22 lbs it requires the use of a bulky infant insert.
San Diego, CA
Highly recommend!
December 13, 2023
I absolutely love this convertible car seat! I bought it for my 8 month old daughter who was getting too big for her infant car seat and needed a bigger seat that was also slim enough for our car. This was the perfect seat! I originally purchased one from Graco, and it just did not work for us as it was really uncomfortable for my daughter. After doing some research, we decided to switch to Britax and decided on the Poplar, and we 100% loved it and would highly recommend! It is made of really good quality and it looks so much comfortable than other brands we looked at. My daughter absolutely loves it! I also love that it is super easy to install, and the click-tight is super nice!
  • - comfortable
  • - good quality
  • - safe wash
  • - click-tight
  • - easy installation
  • - slim
Los Angeles, California
Verified Buyer
No Headrest Comfort!
December 12, 2023
The headrest has zero comfort and definitely compromises the premium Britax comfort! It is pretty and seems like a space-saving option but I'm extremely disappointed with it and currently trying to return it.
  • Spacesaver
  • Lacks the Britax premium comfort that I have been loyal to Britax for. The headrest is disappointing.
Verified Buyer
great for 3 across close in age
December 4, 2023
I use 2 with a ride safer vest in the 3rd row of a Honda Odyssey van
Verified Buyer
Easy install, comfy fabric
November 30, 2023
Love this car seat. It fits in all the seats I've tried it in, super cozy and easy to install correctly with the seatbelt. Cupholders can be removed which is great for tight spaces or baby doesn't need.
Customer Q&A