The Best Convertible Car Seats for Small Cars

When you have triplets, you are likely going to be struggling to find a way to fit them all in your small car! Many convertible car seats just aren’t meant to fit three kids in one row, and who who wants to buy a new car when there are already a hundred other new baby expenses? Instead of upgrading your car, you can easily upgrade your car seats. Here are the best convertible car seats for small cars that you and your triplets will love.

The Best Convertible Car Seat for Small Cars

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Graco SlimFit3 LX 3 in 1 Car Seat | Space Saving Car Seat Fits 3 Across in Your Back Seat, Katrina
Combi Coccoro Streamlined Lightweight Convertible Car Seat| 3 Across in Most Vehicles| Ideal for Compacts | Quick Install | 50% Lighter Than Other Leading Brands| Tru-Safe Impact Protection| Licorice
Britax Marathon ClickTight Convertible Car Seat, Verve
Cosco Mighty Fit 65 DX Convertible Car Seat (Heather Onyx Gray)
Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Black Jet
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Graco SlimFit3 LX 3 in 1 Car Seat | Space Saving Car Seat Fits 3 Across in Your Back Seat, Katrina
Combi Coccoro Streamlined Lightweight Convertible Car Seat| 3 Across in Most Vehicles| Ideal for Compacts | Quick Install | 50% Lighter Than Other Leading Brands| Tru-Safe Impact Protection| Licorice
Britax Marathon ClickTight Convertible Car Seat, Verve
Cosco Mighty Fit 65 DX Convertible Car Seat (Heather Onyx Gray)
Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Black Jet
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$299.99
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$199.99
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Graco SlimFit3 LX 3 in 1 Car Seat | Space Saving Car Seat Fits 3 Across in Your Back Seat, Katrina
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Graco SlimFit3 LX 3 in 1 Car Seat | Space Saving Car Seat Fits 3 Across in Your Back Seat, Katrina
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$259.99
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Combi Coccoro Streamlined Lightweight Convertible Car Seat| 3 Across in Most Vehicles| Ideal for Compacts | Quick Install | 50% Lighter Than Other Leading Brands| Tru-Safe Impact Protection| Licorice
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Combi Coccoro Streamlined Lightweight Convertible Car Seat| 3 Across in Most Vehicles| Ideal for Compacts | Quick Install | 50% Lighter Than Other Leading Brands| Tru-Safe Impact Protection| Licorice
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Britax Marathon ClickTight Convertible Car Seat, Verve
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Britax Marathon ClickTight Convertible Car Seat, Verve
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$299.99
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Cosco Mighty Fit 65 DX Convertible Car Seat (Heather Onyx Gray)
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Cosco Mighty Fit 65 DX Convertible Car Seat (Heather Onyx Gray)
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Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Black Jet
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Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Black Jet
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$199.99

What is a Convertible Car Seat?

A convertible car seat is designed for use from birth until a fairly high weight, typically 40 to 80 pounds. It will both rear face and forward face, and some convert to high back boosters after your child outgrows the weight limit. Convertible car seats are not meant to be taken out and carried around like you would with an infant seat.

How did you pick the best car seats for three across?

When looking for car seats that would work in our small car, we used the following criteria. We made sure the car seat was safety tested with high ratings for both infants and toddlers. We looked only for seats that would fit three across even in small cars. We made sure the seats were a good value and would last for many years.

How do I measure for a narrow car seat?

If you need to fit triplets together in one small car, you must look for a narrow seat. Before making your purchase, measure the backseat of your car to see how much room you have to work with. Then, measure your children as well. You need to make sure they fit within the parameters that the car seat can accommodate!

If you need to fit triplets together in one small car, you must look for a narrow seat. Before making your purchase, measure the backseat of your car to see how much room you have to work with. Then, measure your children as well. You need to make sure they fit within the parameters that the car seat can accommodate!

The 5 Narrowest Seats on the Market

We have done a lot of research so that you don’t have to. Check out the following reviews to learn more about the best convertible car seats for small cars.

1. Graco SlimFit3 LX 3 in 1 Car Seat

Graco SlinFit3 LX is one impressive convertible car seat. Made by Graco, one of the well known car seat brand in the USA, It was created to fit a niche market for those who need a slim chair, but also want style, safety, and long lasting durability. This narrow all-in-one car seat grows with your child.

Features:

  • 16.7” across at widest point
  •  Weighs 19.2 lbs
  •  Fits children 5 – 100 lbs
  •  No-rethread simply safe adjust harness
  •  Fit 3 Car Seats at Every Stage

The Graco SlimFit3 LX will fit three across in almost any car, even compact cars. It installs like a dream. The seat cover is easy to remove and machine washable. Since you will be able to use the seats for an exceptional amount of time, being able to clean it without much work is essential.

Pros:

  • High safety rating
  • Lasts from infancy through age 4+
  • Slim, Comfortable Design
  • Easy to install and reinstall

Cons:

  • Expensive

Graco SlimFit3 LX 3 in 1 Car Seat | Space Saving Car Seat Fits 3 Across in Your Back Seat, Katrina
  • Fits 3 car seats across, saving space in your back seat without compromising on the safety you trust and the features you need
  • 3-in-1 car seat grows with your child from rear-facing harness (5-40 lb) to forward-facing harness (22-65 lb) to highback booster (40-100 lb)
  • Measures 16.7 inches wide, with a spacious seat for your child's comfort and a slim design for more room in the back seat
  • Graco ProtectPlus Engineered: a combination of the most rigorous crash tests that helps to protect your child in frontal, side, rear & rollover crashes
  • 10-position No-Rethread Simply Safe Adjust Harness System allows the headrest and harness to adjust together

2. Combi Coccoro Convertible Car Seat

The Combi Coccoro is the slimmest seat on our list, practically promised to fit three across for your triplets, no matter how small your car is. Created by the Combi company, originally of Japan, this seat was designed to fit into small spaces while costing much less than some other luxury seats available today.

Features:

  • 15.5” across at widest point
  •  Weighs 14.3 lbs
  •  Fits children 3 – 40 lbs

The Coccoro is lightweight and easy to install. It also comes in a nice variety of color combinations. It can fit the smallest of babies, so it is great for those little ones who were born early. The upper weight limit of 40 lbs means that this seat probably won’t last through all of the preschool years, unless your child is smaller than average.

Pros:

  • Great for smaller kids and infants
  • Rear and forward facing capabilities
  • Comes with an infant positioning insert
  • Latch system and 5 point harness are easy to use

Cons:

  • Not good for larger/taller children

Looking for a bargain? Check out the different colors available. Sometimes you can find the less popular colors at a significant discount if you look at all the options. 

If you need replacement parts, they are easy to find through the Combi website, and this seat is under a one year warranty as well. The best place to buy is Amazon, where you can score free shipping and free returns on most color combos!

Combi Coccoro Streamlined Lightweight Convertible Car Seat| 3 Across in Most Vehicles| Ideal for Compacts | Quick Install | 50% Lighter Than Other Leading Brands| Tru-Safe Impact Protection| Licorice
  • TRU-SAFE: Combi utilizes Tru-Safe Side Impact Protection in its Convertible Car Seat. This offers deep side walls and a layer of energy absorbing foam to distribute crash energy away from your baby and toddler’s neck, head and spine. The removable infant insert also provides proper positioning and comfort for smaller children.
  • COMPACT, LIGHTWEIGHT AND THREE ACROSS: The Coccoro Convertible Car Seat was designed with small spaces in mind. At 15.5 inches in width, the Cocorro easily installs in tighter spaces and smaller cars. This creates an easier installation, allows for “Three Across Installation” and also easier portability. It is FAA certified, so convenient travel became easier with this convertible car seat! The Coccoro is one of the few travel car seats.
  • COMFORTABLE AND EASE OF USE: The Coccoro Convertible Car Seat has a buckle with an indicator that provides a visual cue when the harness is securely buckled. The Coccoro also features a tether connector strap for Rear-Facing tethering.
  • WASHABLE: The Coccoro is machine washable. Please check your instruction manual before proceeding.
  • WEIGHT AND HEIGHT: The Cocorro convertible car seat accomadates a baby and toddler from 3 – 33lbs Rear Facing and 20 – 40lbs Forward Facing. The Minimum height for your child is 19 inches and the Maximum Height is 40 inches.

​​​3. Britax USA Marathon ClickTight Convertible Car Seat

Britax is a well known brand, famous for its affordability and durability. This convertible seat will fit three across in all but the smallest of cars.

Features:

  • 18.5” across at widest point
  •  Weighs 28.4 lbs
  •  Fits children 5 – 65 lbs
  •  Easy to use ClickTight System helps get a secure install every time

The Marathon is the largest seat on our list, so definitely double check your car measurements. This seat is very safe, since it offers a unique installation system that is user-error free. Most car seats are not installed correctly, which is why this one is safer than average.

Pros:

  • Lasts from infancy through age 4+
  • Extremely safe harness system
  • Very easy to install
  • Made in the USA

Cons:

  • Expensive
  • Taller than average

This seat may be more expensive than some, but it should last you and your family for many years. If you are looking for a great price, also check out Target, which sells it for a great price and offers free shipping! Don’t forget there is a one year warranty to cover defects.

Britax Marathon ClickTight Convertible Car Seat, Verve
  • Easy installation: Patented click tight makes car seat installation as simple as buckling a seat belt
  • No rethreading, ever: 14 position harness, 2 position buckle for a comfortable fit as your child grows
  • Relax and recline: 7 recline positions ensure comfort and the best vehicle installation angle
  • Surrounded in safety: A layer of side impact protection, steel frame and impact absorbing base
  • Fits: Rear facing 5 to 40 pounds and forward facing 20 to 65 pounds; dimensions: 23 x 18.5 x 23.5 inches (LxWxH); shoulder width 16 inch

4. Cosco Mighty Fit 65 DX

This Cosco seat is an excellent choice for the budget shopper, and one of the best car seats for three across installation.

Features:

  • 17” across at widest point
  •  Weighs 14 lbs
  •  Fits children 5- 65 lbs

The great thing about the Mighty Fit is that not only is it narrow, but it is also compact. Drivers and passengers will be able to have plenty of legroom, since this car seat doesn’t take up a ton of space. For such an inexpensive seat, it really will last you a long time

Pros:

  • Stylish design and colors
  • Very affordable
  • Machine washable and dryer safe
  • Side impact protection

Cons:

  • Tricky to install

If you buy this seat on Amazon you will score free shipping both ways, and you have four cute and colorful options to choose from. There is also a standard one year warranty on this product.

Cosco Mighty Fit 65 DX Convertible Car Seat (Heather Onyx Gray)
  • With 2 modes of use, this extra comfortable LATCH equipped Cosco car seat accommodates infants from 5 pounds up to toddlers weighing 40 pounds in rear facing mode and kids up to 65 pounds in forward facing mode. Its compact design also makes it easier to manage through airport security checks
  • The 5 point harness adjusts easily from the front of the seat and features 5 heights and 3 buckle locations
  • Built in side impact protection keeps your little 1 extra secure; Designed to be just the right size, the seat takes up less space while rear facing so parents can have more leg room
  • Three of these seats can fit side by side in the back seat of most cars, perfect for growing families
  • With plush padding and premium fabric, this seat gives your child an extra comfy ride; Easy to clean, the fabric car seat cover is machine washable and dryer safe

5. Diono Radian 3R Car Seat

The Diono Radian 3R designed to be a little more affordable than it’s counterpart, but it fits just as well when you need to have a narrow car seat

Features:

  • 17” across at widest point
  • Weighs 25.9 lbs
  • Fits children 5 – 120 lbs

The Diono Radian 3R is affordable and easy to install. It comes in a variety of bright colors that will fit any personality.

Pros:

  • Reinforced steel core and side walls
  • Lasts from infancy through age 4+
  • Colorful options
  • Easy to install and reinstall

Cons:

  • No cup holders

Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Black Jet
  • REAR-FACING FOR LONGER: This slimfit convertible car seat is designed and engineered to keep your child rear facing even longer up to 50 lb/ 22. 7 kg, approx. 4 years old
  • HIGH BACK BOOSTER: Keep your child safe and comfortable with the high back booster seat mode now up to 120 lb, 54 kg. The high back booster adds an extra layer of protection and comfort for any child transitioning into booster mode.Shell and Components: Spot clean
  • 10 YEARS ONE CAR SEAT: With 4 ways to travel safely from birth to booster, the Radian 3R adapts as your child grows to offer a custom adjustable fit from birth to 120 lbs
  • REINFORCED STEEL CORE: Mechanically engineered, reinforced steel core, made from automotive grade high density plastic and steel to create the ultimate protection for your child
  • THE ORIGINAL 3 ACROSS: Built with our famous radian slim fit convertible design, to fit 3 across in most vehicles without compromising child or passenger comfort. Feel safe having your children secure in the backseat

If you need a narrow car seat, this list has you covered! In the end, the Britax offers the extremely safe harness system, and the Cosco will give you more bang for your buck. Overall, if you must find the best convertible car seats for small cars, you can’t go wrong with any of these choices!

Related Posts:

  1. The safest convertible car seat
  2. Essential Baby Gear for Triplets
  3. The Best Narrow High Back Booster Seat with 5 Point Harness

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