Having a car seat that is safe and comfortable for your little one is very important. But what happens when you have three children needing a car seat?

As a twin mom plus one, I know all too much about the need for car seats that are slim and narrow. In my family, we made the mistake of investing in convertible car seats that were very wide. When baby #3 came along, we ended up having to get all new car seats that would fit 3 across.

That’s why I have assembled this list! I have taken learnings from my own personal experiences to create a list of the best narrow car seats that fit 3 across in most cars. Additionally, you will also find a summary of which car seats are the slimmest for each car seat type.

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What Makes a Car Seat Narrow?

A narrow car seat is defined as having an average width of 17 inches or less. You can also think of a narrow car seat as something that could fit three car seats across comfortably in a smaller car.

Reasons To Get Narrow Car Seats

There are various reasons you may be looking to purchase narrow car seats. The top two reasons people typically need smaller width car seats include the following:

  • Having more than one car seat in a car – especially when you need to fit three car seats across and own a small crossover SUV or a sedan.
  • If you plan to have more children – it is a good idea to get this kind of car seat if you may plan to have more children in the near future.

Types of Slim or Narrow Car Seats

Car seats should adapt and change as your child grows. Their weight and height changes, and therefore the car seat requirements will need to be adjusted too.

These different car seat sizes help ensure safety at all times, as well as, comfort for your kids. The three stages of car seats are listed below. We will be reviewing the best narrow car seats in each of these categories.

  • Infant Car Seats
  • Convertible Car Seats
  • Booster Seats

Which Infant, Convertible, & Booster Car Seats Are Narrowest?

If you are looking for a quick summary of the absolute narrowest car seats I recommend, checking out the list below. If you prefer to read a more detailed review of the best narrow car seats – keep on scrolling.

Narrowest Infant Car Seat

The Baby Trend Secure Snap Tech 35 is the slimmest infant car seat on this list at 16.25 inches.

Slimmest Convertible Car Seat

As far as the narrowest convertible car seat, there is actually a three-way tie. The Graco SlimFit3 LX, the Graco True3Fit LX, and the Baby Trend Trooper all come in at 16.7 inches.

Narrowest Booster Seat

For the slimmest booster seat, the Maxi-Cosi Rodi Sport is only 14 inches when the cup holder is not included. If you prefer a cup holder, then the Graco Affix is the narrowest at 16.5 inches.

Best Narrow Infant Car Seats

Let’s now take a detailed look at the best narrow car seats. First up you will find my list of the safest and best narrow infant car seats on the market.

Chicco Fit2

The Chicco Fit2 has a width of 17 inches and it is therefore the broader of the 3 on the list, but still fairly narrow if you need more than one car seat in your car. Chicco has always had a good name for quality and safety standards, and this car seat is no different.

The Chicco Fit2 is a rear facing infant car seat and as with some of the others reviewed, this car seat clicks in and out of a car seat base quickly and easily. It has a 7-position head rest and the 2-stage base adjusts, allowing it to grow with your baby up to 24 months old.

This car seat can be used for infants as small as 4 lbs and can also be adjusted and converted to suit a child up to 35 lbs. Additionally, this car seat is compatible with the lightweight Chicco KeyFit Caddy frame stroller.

Baby Trend Secure Snap Tech 35 Infant Car Seat

For an economical narrow car seat choice there is the Baby Trend Secure Snap Tech 35 infant car seat. This car seat is quite slim at 16.25 inches, making this seat the narrowest of the infant car seats on our list.

The minimum weight for this car seat is 5 lbs and the maximum weight is 35 lbs. It comes with a 5-point safety harness. Releasing the seat from the base is a simple one hand operation. Another great feature of this product are the four reclining positions for its base.

Clek Liing

The Clek Liing infant car seat has a width of 16.9 inches making it the second narrowest product on the market when it comes to infant car seats.

This particular car seat comes jam-packed with safety features including an energy absorbing metal load leg, a shell lined with EPP foam for better side impact protection, and the Clek signature rigid-LATCH base, which offers 7 reclining positions.

The Clek Liing is also great for a rear-facing position. The one-handed quick release from the base is so easy and convenient. With this being the second narrowest on the market, it makes it super efficient if you need to have 3 car seats next to each other across the backseat.

Best Narrow Convertible Car Seats For Fitting 3 Across

Next, let’s review the best narrow convertible car seats, especially for fitting 3 across in your vehicle. The main things you want to look at is obviously the width, but also safety features according to your growing child. Here is my list of the best slim convertible car seats available to you.

Diono Radian 3RXT

You may of may not have heard of Diono Radian seats before, and if you have you will know that this brand is the original three-across adjustable convertible car seat. The Diono Radian 3RXT comes in with a width of 17 inches.

What makes this convertible car seat so amazing and trusted by over a million parents worldwide? The fact that it now has a rear-facing capability which means that you will get up to 10 years of safety for your growing child from one car seat.

You can rest assured that with the padding and safety features of this trusted brand for your newborn up to 4 years old, can be safely and comfortably secure in a rear-facing position. When your child moves to a front facing position, the adjustable head rest grows with your child. Overall, this is one of the best convertible seats on the market if you want something to carry you through the years without changing seats.

Graco SlimFit3 LX 3-in-1

The Graco SlimFit3 LX convertible car seat also grows with your child. Starting with infants from 5 lbs it will convert and adjust with your child all the way up to 100 lbs (as a highback booster seat).

This car seat is my personal choice and I have successfully used them for a 3-across setup in my Mazda CX-7 and the second row of a Honda Pilot. The width of the Graco SlimFit3 LX is 16.7 inches.

That makes this car seat perfect for a three-across setup in your vehicle. The LATCH system allows for quick installation and removal of the car seat. You will also find that the 4-position recline system allows for your infant to stay comfy and safe at all times.

Please note you want to purchase the Graco SlimFit3 LX NOT the regular Graco SlimFit. On Amazon the SlimFit3 LX is described as “SlimFit w/ 3-Across Fit”. The seat you want is the one linked above.

Baby Trend Trooper

The Baby Trend Trooper has a width of 16.75 inches making it one of the slimmer convertible car seats on our list. As with all the others we have discussed, this car seat can also be used in three stages for rear-facing, forward facing, and booster.

With its narrow physique you can be sure it will fit really well in a three-across setup in most vehicles. The Baby Trend Trooper is quick and easy to install and the bubble indicator lets you know which is the most preferred angle and position. An added feature for this convertible car seat is that the cushioning and head protection is perfect for preemie babies too.

Safety 1st Jive 2-in-1

The Safety 1st Jive 2-in-1 is also an amazing product and definitely worth a mention. It has a width of 18.1 inches and converts from rear-facing to front facing effortlessly.

The rear-facing position is perfect for infants from 5 lbs through 40 lbs, and when converted, it can be used up to 65 lbs. The Safety 1st Jive is perfect when you want to fit three-across a back seat. It has added safety features such as side impact protection and a 5-point harness function.

Cosco Mighty Fit 65 DX

If you are on a tight budget the Cosco Mighty Fit 65 DX is a perfectly safe choice for a narrow car seat. This seat can be used for both rear facing (with a minimum weight of 5 lbs) and as a forward facing convertible seat (with a maximum weight of 65 lbs).

The width of the Mighty Fit seat measures 18.5 inches (without the cup holder attached) and it comes equipped with the LATCH system. It can fit 3 across in most vehicles.

Graco True3Fit LX

Graco True3Fit convertible car seat.

The Graco True3Fit LX has a width of 16.7 inches. You can rest assured that you will be able to fit this seat 3-across.

The Graco True3Fit has a minimum capacity of 5 lbs and a maximum weight limit of 100 lbs because it is a 3-in-1 car seat. You can use it as a rear-facing seat, then a forward facing convertible seat, and finally a high back booster seat.

It has added safety features such as side impact protection and the exclusive Graco ProtectPlus Engineered technology, which has withstood numerous crash tests.

Clek Foonf

Considered the mother of all car seats the Clek Foonf is designed to keep your child rear-facing up until 4 years of age. It is adjustable and can be used in all three stages, rear-facing, forward facing and then as a booster.

The Clek Foonf is 16.9 inches in width, and is therefore one of the narrowest seats on the market. It comes jampacked with safety features including the patented REACT energy management system, which allows for effortless installation and advanced side impact protection. The narrow width clearly makes the Clek Foonf great for a three-across setup.

Britax Marathon

The ClickTight installation system allows for the Britax Marathon to be easily and safely installed by any parent. It also fits well in most vehicles when used as part of a three-across setup.

The width is 18.5 inches, making it a little higher up on the list when it comes to width for narrow car seats. As with the other seats mentioned, the Britax Marathon also has superior side impact protection and various other safety features synonymous with the Britax brand.

Peg Perego Primo Viaggio Convertible Kinetic

The Peg Perego Primo Viaggio Convertible Kinetic car seat can accommodate children from 5 lbs through 65 lbs. The width is 18.75 inches and it works very well in a three-across setup in most vehicles.

Peg Perego is also synonymous with quality and safety features and is always on top of many car seat lists because of this.

Top Slim Booster Seats For Toddlers

Slim booster seats usually have a backrest support and will need to be used with a seat belt. You will want to look at narrow booster seats if you wish to have a three across setup in a smaller vehicle and perhaps have more than one toddler.

Graco Tranzitions

The Graco Tanzitions booster is a 3-in-1 seat with a width of 17.4 inches. It has adjustable harnesses and can be used as both a forward facing convertible car seat, a high back booster seat, and a backless booster seat.

You can use this seat starting at 22 lb, until your child reaches 100 lb. It is a lot narrower than most booster seats out there, while still providing comfort and protection for your child. The Graco Tranzitions seat is lightweight, compact, and perfect for busy parents on the go.

Maxi-Cosi Rodi Sport

The Maxi-Cosi Rodi Sport comes equipped with rigid LATCH connectors to make sure the seat stays in place, and making installation and removal a breeze. This booster seat is approved for children between 40 and 100 lbs in weight.

The width of the Maxi Cosi booster seat is only 14 inches without the cup holder. When you add the cup holder the width goes up to 21 inches. This booster seat offers superior comfort and protection for your child, and works in a three-across setup in most vehicles (especially if you don’t use the cup holder).

Graco Affix

Graco Affix high back booster seat.

The Graco Affix Highback booster seat is perfect for safely transporting your older child in the weight range of 40 lbs through 100 lbs. The of width of the Graco Affix is 16.5 inches making it the slimmest by far on the narrow booster seat list.

The height of the high-back booster is adjustable up to 57 inches. This booster seat also has a front-adjust Latch system, which means the booster is securely connected to your vehicle’s seat. The Graco Affix comes with cup holders perfect for sippy cups and snacks, which your children are sure to enjoy.

17 narrow car seats that fit 3 across.

Are Narrow Car Seats As Safe As Normal-Sized Car Seats?

YES! All the car seats listed have various enhanced safety measures in place. There is no difference in the safety of narrow car seats and regular-width car seats. Narrow car seats generally all provide the same 5-point harness systems and side protection that a normal car seat offers.

Now that you know the best slim and narrow car seats on the market, you can go ahead and invest in the one you like in order to save space or fit 3 car seats across your vehicle.

In conclusion, we can honestly say that there are so many options available when it comes to narrow car seats to carry you and your child through the various car seat stages as he or she grows. To summarize, these are the key points.

  • Ideally the seat should be adjustable and have various reclining positions for safety and comfort
  • Narrow car seats are slim enough to fit three across in most vehicles
  • All the car seats listed above are built to provide adequate safety and protection for your child

Good luck finding the perfect car seat for your child and family, I hope you found some information to help you in your search.

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  1. Some of widths listed here aren’t correct. The BabyTrend Trooper is 17.5″. The MightFit is 18.5″. This article has led me to purchase a few of these carseats only to have to return them because they don’t fit in the car. Please update the article.

    1. Hi Louise,
      Thank you so much for your comment and I am so sorry you ended up having to return some seats. I did some investigating and The BabyTrend Trooper is advertised heavily as being 16.75″ and able to fit 3 car seats across in most vehicles. Please check out the BabyTrend website and video here: https://babytrend.com/products/trooper-3-in-1-convertible-car-seat. It does say in the product dimensions that the width is 17.5″ though, so I found that interesting but not unusual. When writing and updating this article this is a common problem for some reason. Often I have found conflicting information on the actual dimensions of the car seats. I do the best I can with the information I can find. So again, thanks for the additional info. As far as the Mighty Fit is concerned, Amazon has it listed at 17″. But further investigation on other websites indicated that the width of this seat is actually 18.5″ as you said, with it fitting 3-across in most vehicles. I updated the article accordingly.

    2. The baby trend trooper is 16.75 in wide. I have 3 of them in my vehicle and I measured them before installing them!! Widest parts are across the shoulders and where the cup holder is