Narrow Car Seats: Booster, Convertible, Infant and 3-in-1 – Which Option for The Smaller Car?

Three children sitting on the lawn

When looking for narrow car seats, booster, convertible, infant and 3-in-1 options, they are all available for the smaller car or bigger family. Picking the best one takes some time though when you need to factor in some important key features. My top pick is the Maxi-Cosi Rodifix Booster Car Seat for its narrow dimensions, safety features and ease of use.

An average width size of 17 inches is considered the best size for most cars especially if you want to go three across. I’ve reviewed 8 products ranging between 16 to 22 inches wide so it should be easy to make a suitable pick from my list. I’ve also discussed the safety of narrow car seats and other key features to look out for when choosing your car seat.

Table Of Contents

My Top Picks

Best Overall – Maxi-Cosi Rodifix Booster Car Seat

Maxi-COSI Rodifix Belt Positioning Protective Child Booster Car Seat with Adjustable Headrest for Kids 40 to 120 Pounds, Nomad Blue

If you’re looking for one of the best narrow booster car seats, then check out this one. I love the design too. It’ll make your kid feel like they’re the pilot of their own plane every time they take a ride in this one.

Who It’s For

This is great if you want a narrow car seat to grow with your child up to 120 lbs.

Why You Should Consider It

This belt-positioning booster slim car seat measures 28.5 x 17.75 x 15.2 inches and takes a child up to 57 inches high. The weight recommendations are from 40 to 120 pounds. Soft but firm and expandable side wings give added protection when using the adjustable headrest.

The rigid latch system ensures the seat is installed securely. A front access recline feature gives more flexibility for a better fit in the vehicle. And reclining positioning gives your child a more comfortable ride too. The cushioning is not only ultra-comfortable but the covers are easy to remove for washing.

Your older child can easily buckle themselves in safely which will make them feel pretty cool as the “Big Kid”! What’s more, this car seat has been awarded the 2020 NAPPA Award.

Product Information

  • Dimensions: 28.5 x 17.75 x 15.2″
  • Item weight: 17.16 lbs.
  • Weight: 40 – 120 lbs.
  • Material: Not specified


  • AirProtect technology for added head protection during collision
  • Very easy to install and remove
  • Safe and secure latching system


  • No cup holder included
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Best Value – Diono 2020 Radian 3R 3 in 1 Convertible Car Seat

Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Gray Slate

If you want to keep your child rear-facing for longer, then this convertible car seat is the answer you need. It allows kids up to 50 pounds (+/- 4 years old) to sit rear-facing in the car while you’re traveling.

Who It’s For

For parents looking for a good three across option from newborn to 10 years old.

Why You Should Consider It

This slim-fit car seat measures 16 x 17 x 28.25 inches and you can start using it with your newborn, going up to 10 years old. This all-in-one car seat is constructed with reinforced steel core made with automotive high-grade steel.

The Diono SuperLatch system gives you peace of mind that the seat is securely installed when you hear an audible “click” sound. It’s made with sturdy materials without compromising on your child’s safety or comfort.

It includes a 5-point harness system and comes in a range of beautiful colors. Diono’s radian slim-fit design was the original three across car seat design. So they know what they’re doing when it comes to narrow car seats.

Product Information

  • Dimensions: 16 x 17 x 28.25″
  • Item weight: 26.1 lbs.
  • Weight: 5 – 120 lbs.
  • Material: Plastic/steel/polyester/spandex


  • Sturdy, soft and comfortable
  • Super easy to clean
  • Buckles are easy to use


  • No cup holders included
  • Heavy
  • Not easy to install
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Best Narrow Convertible Seat – Clek Fllo Convertible Car Seat

A Canadian-made product, this falls neatly into the narrow convertible car seat category! You’ll easily get three across in your car and great for rear-facing seating options.

Who It’s For

Ideal for a family with up to three kids all under the age of six years old.

Why You Should Consider It

This comfortable car seat lined with 100% Merino wool measures in neatly at 22 x 16.9 x 26 inches. The frame is solid and secure being constructed with steel. The Clek energy-absorbing crumple technology absorbs all energy created during an impact, keeping your child well-protected.

The rear-facing seating option has been designed to safely accommodate your child up to 50 lbs. And, with its steel anti-rebound bar is simply another safety measure put in place to keep your child safe during a collision.

Similar to the Foonf model, the materials are free of chlorinated and brominated flame retardants.

Product Information

  • Dimensions: 22 x 16.9 x 26″
  • Item weight: 25 lbs.
  • Weight: 14 – 65 lbs.
  • Material: Steel (frame) / merino wool (seat covering)


  • Merino wool breathable and comfortable in both hot and cold climates
  • Comfortable both rear and front-facing seating
  • Easy to install as long as you follow instructions


  • Expensive
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Best for Bigger Cars- Graco Tranzitions 3-in-1 Harness Booster Seat

Graco Tranzitions 3 in 1 Harness Booster Seat, Basin , 18.9x10.47x33.5 Inch (Pack of 1)

This car seat is ideal for the bigger kid growing up from toddlerhood. It’s narrow enough to fit into smaller cars and you can even fit three across for bigger cars and families.

Who It’s For

This is great for kids from 22 pounds to 100 pounds.

Why You Should Consider It

This forward-facing seat converts effortlessly from a harness booster (22 – 65 lbs.) to a highback booster (40 – 100 lbs.) to a backless booster (40 – 100 lbs.) at different stages of your child’s growth. It measures in at 26.5 x 18 x 17.4 inches (L x W x D).

You can adjust the seat to 8 different height positions with Graco’s No-Rethread Safe Adjust Harness System. It’s lightweight, portable and easy to clean with the car seat padding, body support and harness cover being machine washable.

Open-loop belt guides will ensure you install the seat correctly with the car seat’s safety belt. All Graco car seats are designed to meet all stringent safety standards.

Product Information

  • Dimensions: 26.5 x 18 x 17.4″
  • Item weight: 20 lbs.
  • Weight: 22 – 100 lbs.
  • Material: Metal


  • Easy to install and adjust
  • Works well for 3 across situations
  • Sturdy and comfortable


  • Bottom buckle may be tricky to fasten
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Best Narrow Infant Car Seat – Graco SlimFit 3 in 1 Car Seat

Graco SlimFit 3-in-1 Convertible Car Seat, Ultra-Space-Saving Design, Darcie, Suitable for Rear and Forward-Facing, Highback Booster Seat with 10-Position Headrest

I’ve talked about this car seat before so read all about it for a more in-depth review here. It’s another great narrow car seat option for your younger baby.

Who It’s For

This works well for babies from 5 lbs. growing up to 100 lbs.

Why You Should Consider It

This space saver car seat, measuring in at 21.5 x 19.9 x 25.5 inches, can be used as a rear-facing harness (5 – 40 lbs.), front-facing harness (22 – 65 lbs) to a highback booster (40 – 1000 lbs).

The 10-position headrest and adjustable no-rethread harness system allow this seat to grow with your child. It also includes a 4-recline position feature for added comfort. The Graco InRight Latch push button ensures correct installation.

The steel-reinforced frame gives you peace of mind this car seat is secure and long-lasting. A dual cup holder is included and can be rotated away to give more space in the back seat.

Product Information

  • Dimensions: 21.5 x 19.9 x 25.5″
  • Item weight: 19.47 lbs
  • Weight: 5 – 100 lbs.
  • Material: Steel (frame)/polyester (fabric)


  • Harness automatically adjusts when the headrest is lifted/lowered
  • Easy to install
  • Lightweight


  • Holes/cracks on side of seat allow biscuit crumbs to get stuck inside
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Best Three Across Option – Clek Foonf Convertible Car Seat

This super-slim car seat is possibly one of the best narrow car seats for three across options. And, it’s constructed free of brominated and chlorinated flame retardants giving you extra peace of mind your baby is safe in the car.

Who It’s For

For parents with super-small cars looking for a car seat to accommodate rear-facing for the older baby up to 50 lbs.

Why You Should Consider It

This rear-facing (14 – 50 lbs.) and front-facing convertible seat (22-65 lbs.) is designed with energy-absorbing crumple technology. It can be used from birth if you buy the insert specifically designed to accommodate newborns in this car seat.

This seat measures 17.5 x 16.9 x 28 inches (L x W xD). The seating cover is 100% Merino wool which not only adds comfort for your child but is moisture and stain-resistant. You have the option of 3 recline positions.

Foonf’s Rigid-Latch system ensures you install the seat securely and efficiently. Side impact protection is offered with an adjustable headrest with deep side wings. The frame is solid with metal construction. A steel rebound bar for rear-facing installation offers extra protection during an impact.

Product Information

  • Dimensions: 17.5 x 16.9 x 28″
  • Item weight: 33 lbs.
  • Weight: 14 – 65 lbs.
  • Material: Metal (frame)/merino wool (seat covering)


  • Belts are well-padded for comfort
  • Foam padding lines entire seat bucket
  • Plenty of leg room in rear-facing position


  • Heavy
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Best for Height – Peg Perego Viaggio Flex

Peg Perego Viaggio Flex 120 - Booster Car Seat - for Children from 40 to 120 lbs - Made in Italy - Licorice (Black)

This Italian made booster seat has a narrow profile and all the necessary features to grow with your child. You can be sure your child will be safe and secure when taking a car ride in it.

Who It’s For

For families needing to safely accommodate children between 40 and 120 pounds whenever traveling in the car.

Why You Should Consider It

This forward-facing seat includes many nifty features to ensure your growing child is not only secure but comfortable. It’ll accommodate a maximum height of 63 inches and measures 17.25 x 22 x 26 inches.

The headrest can adjust vertically into 5 different positions. The backrest also has 3 adjustable positions (and can be fully removed when not being used) and the side wings expand out up to 3 times. PLUS, you have the option of 5 reclining positions.

The integrated latch system ensures the seat is securely installed. The aluminum-reinforced backrest protects against whiplash and EPS technology in the side wings and headrest offer greater energy absorption during a collision.

Product Information

  • Dimensions: 17.25 x 22 x 26″
  • Item weight: 14.8 lbs.
  • Weight: 40 – 120 lbs.
  • Material: Plastic/steel/polyester


  • No armrests make it easier for buckle to be fastened
  • Highly padded fabrics for comfort
  • Seat belt slides smoothly through belt guide


  • Price tag could be hefty for some parents
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Best Budget – Evenflo Big Kid Amp High Back 2 in 1 Belt-Positioning Booster

Evenflo Big Kid Amp High Back 2-in-1 Belt-Positioning Booster, Sprocket

This high back booster seat easily converts to a backless booster seat when your child is ready to transition. Give your child the Big Kid status they deserve by getting them this booster seat for their car rides.

Who It’s For

For parents wanting a booster seat for kids at least 4 years old.

Why You Should Consider It

This booster seat is great for use with the vehicle’s seat belt while giving your child extra safety in the car. It’s best suited for children weighing between 40 and 110 pounds and a maximum height of 57 inches. It measures 16.5 x 19 x 33 inches.

The headrest offers 6 adjustable positions which can be easily done with one hand. The backrest adjusts as the child grows while at all times ensuring its positioned for safety. An integrated belt guiding system ensures smooth operation when using the seat belt.

Cleaning is straightforward – simply wipe with mild soap and water. The seat pad can be removed for machine washing. Dual cup holders allow your child to keep their juice with them while you’re traveling.

Product Information

  • Dimensions: 33 x 16.5 x 19″
  • Item weight: 8.1 lbs.
  • Weight: 40 – 110 lbs.
  • Material: Metal/plastic/foam


  • Lightweight
  • Easy to install and remove from the car
  • Sleek and comfortable design


  • Not very comfortable for sleeping children
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Narrow Car Seats: Everything I Need to Know

When you start looking for narrow car seats, you need to ask a lot of questions to make sure you get the best one for you and your child’s needs. My research and review of the above products have highlighted many important factors that should be considered. And, I’m not only talking about the size.

The Average Sizes of Narrow Car Seats and Booster Seats

The width measurement of the car seat is what matters when you’re looking for a narrow car seat. The range of sizes for the products reviewed was from 16 to 22 inches with the average size being 17 inches.

Both the narrow infant car seats and convertible car seats average width size was 17 inches. The average size for the narrow booster car seats was approximately 19 inches.

How to Know if a Car Seat Will Fit in My Car?

Whether you’re buying a narrow car seat or a normal size car seat, you need to make sure your car’s back seat will accommodate it. By taking measurements of your back seat and then reviewing the dimensions of the car seat, you’ll have a good idea if it’ll fit comfortably.

If you’re looking to buy a new car and you know you’ll be using car seats in it, check out the following specifications of the car:

  • Second-row hip room
  • Second-row head space
  • Second-row shoulder space

These are normally indicated under the interior dimensions of the car’s features and specifications section. The measurements are normally given in inches.

Narrow Car Seats for Three Across – Can Car Seats Touch Each Other?

Most times, unless you’re driving a large car, three car seats in the back seat are going to touch each other. The right question to ask here is are all three seats securely latched or attached without any interference when needing to reach buckles? With the average size of a narrow car seat being 17 inches, if you’re looking to fit three across you need a back seat area of about 52 inches. If you’re looking at booster car seats and based on the average width being 19 inches, the back seat of your car needs to measure about 58 inches. 

Let’s take the Kia Sportage model. The back seat measures in at 51.2 inches. So, you’ll get three across as long as you don’t exceed the 17 inches width. My car’s back seat (a Honda CR-V) is only 49.5 inches so you’ll seriously battle to get three car seats across in this car.

Before you jump the gun and buy three narrow car seats because they say they’re “slim-fit”, measure your car’s back seat. Also factor in the shoulder and headroom space if you pick the rear-facing car seats for older kids.

If you find yourself forcing seats to fit in because they’re of different designs, you may want to reconsider and get all three seats made from the same brand with the same design. So, car seats can touch each other as long as they still function safely independently of each other.

Are There Safety Concerns With Narrow Car Seats?

All car seats, whether slim-fit design or not, should be fully certified to meet safety standards stipulated by government regulations. All the products reviewed in this article have undergone strict testing requirements to meet these standards.

Of course, it’s up to the parents to ensure the seats are installed and used according to the manufacturer’s instructions. Make sure your child fits within the weight recommendation for whichever car seat they’re using. This way, you can be sure your child is secure while riding in their narrow car seat.

Is a Backless Booster Seat Less Safe Than a High Back Booster Seat?

When converting from a high back booster seat to a backless booster seat you may wonder just how safe they are to use. High back booster seats are considered safer than backless booster seats. However, a backless booster seat is better than nothing at all!

Remember, a high back booster seat includes features such as headrests and side wings, giving your child extra protection should you be in an accident. They also position the seat belt better.

But backless boosters, if well designed, will factor in seat belt alignment so your child is safe at all times. By the time your child is ready for a backless booster, they can also rely on the vehicle’s headrest for support and protection.

It’s important to only use a backless booster seat when your child is older than 4 years, weighs over 40 pounds and the vehicle has both a shoulder and lap belt. The child must also know not to fiddle with the seat belt while traveling.

At What Age Can Your Toddler Sit on a Booster Seat?

Firstly, it helps to know the difference between a car seat and a booster seat. The car seat relies on a harness system to keep your infant secure. The booster seat relies on the car’s seat belt system for strapping your child in.

It’s recommended to keep your child in a car seat with a 5-point harness system for as long as you can. This is normally by the time your child reaches 5 years old. You can also be guided by the manufacturer’s maximum weight and age recommendations when using a harness system.

You can move your child over to a booster seat from 4 years old and many booster seats stipulate this as the ideal age. Ask yourself the following questions before moving your child over to a booster seat:

  • Do my child’s weight and height exceed the recommended maximum requirements for a 5-point harness system?
  • Does my child weigh more than 40 pounds?
  • Can my child travel long distances on a booster seat without slouching or fidgeting with the seat belt.
  • Does my car have headrests?

Watch this video about how to use a booster seat safely.

How to Pick the Best Narrow Seat for Your Baby’s Safe Car Ride

To help you pick the best narrow car seat for your child’s safe ride, I’ve compiled a table highlighting key features and which products reviewed here include these key features.

Key FeatureProduct
Average width size: 17 inches (for average back car seat of 51 inches)/best for three across seating- Clek Foonf Convertible Car Seat - 17.5 x 16.9 x 28″
- Clek Fllo Convertible Car Seat - 22 x 16.9 x 26″
- Evenflo Big Kid Amp High Back 2 in 1 Belt Positioning Booster - 33 x 16.5 x 19”
- Diono 2020 Radian 3R 3 in 1 Convertible Car Seat - 16 x 17 x 28.25″
Adjustable reclining positions for added comfort- Graco SlimFit 3 in 1 Car Seat - 4 recline positions
- Clek Foonf Convertible Car SeatClek Foonf Convertible Car Seat - 3 recline positions
- Peg Perego Viaggio Flex - backrest has 3 adjustable positions
- Maxi-Cosi Rodifix Booster Car Seat - can be placed into a reclining position
Adjustable headrests to accommodate height/growth stages of child- Evenflo Big Kid Amp High Back 2 in 1 Belt Positioning Boostervenflo Big Kid Amp High Back 2 in 1 Belt Positioning Booster - 6
- Peg Perego Viaggio Flex - 5
- Graco Tranzitions 3 in 1 Harness Booster Seat - 8
- Graco SlimFit 3 in 1 Car Seat Graco SlimFit 3 in 1 Car Seat - 10
Lightweight options for easy handling- Evenflo Big Kid Amp High Back 2 in 1 Belt Positioning BoosterEvenflo Big Kid Amp High Back 2 in 1 Belt Positioning Booster - 8.1 lbs.
- Peg Perego Viaggio Flex - 14.8 lbs,
- Maxi-Cosi Rodifix Booster Car Seat - 17.16 lbs.

Final Thoughts

You can find narrow infant car seats, narrow booster car seats, narrow convertible car seats and narrow car seats for three across placement. You can even get a narrow 3 in 1 car seat. But deciding which one is best for you and your child depends on a number of factors such as the car size, safety features, comfort, and ease of use.

I picked the Maxi-Cosi Rodifix Booster Car Seat for ticking all the boxes. Which one would tick all your boxes?

Last update on 2024-05-23 / Affiliate links / Images from Amazon Product Advertising API

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