Graco SlimFit3 LX 3 in 1 Car Seat Review -Best to Fit 3 Across

Graco SlimFit LX 3-in-1 Car Seat

Graco SlimFit3 LX

Overall Rating
Key Features

The SlimFit 3 LX sports a unique fitting aesthetic that is unlike any other car seat in the Graco all-in-one car seat line. Alongside its slim design with two cup holders on both sides, the SlimFit 3 LX not only looks great but has the build quality to match. While it’s narrow enough to fit 3-across seats and it sports enough space for kids to stay in the car seat, the SlimFit3 LX combines practicality and comfort into one.

The ultra-performance is to go through three car seat stages from your kid’s birth until they are no more than 100 pounds in weight or 57 inches tall in height. It’s a pity that the car seat does not allow detaching the back support to make it backless. Overall, though, the SlimFit3 LX is an impressive car seat, but you are paying for the Graco brand.

Graco SlimFit3 LX Review - Slimmest 3 Across Car Seat

Pros & Cons

The good and the bad

What is it best for

Who we recommend it for

Value for Money

Is it worth the price tag?


Dimensions, weight, color, etc


Weight/height limits, airplane, etc

Crash Tests

Safety, FMVSS213, SIP


Install with LATCH or seat belt


Other car seats to consider

1. Pros and Cons



2. Who Is It Best For?

Will the Graco SlimFit3 LX be a good option for your child and your family?

There are two types of parents who will have the Graco SlimFit3 LX to travel by their kids in the car.

The first are those looking for an upgrade from a convertible car seat and want something with extendable and longer riding time and comfortable riding. 

The second are those on the hunt for a slim scooter. But bear in mind, the SlimFit3 isn’t the smallest or the lightest – So I only recommend it for big families who have several children and want to ride them in the car for family trips. 

If this sounds like you, you can’t go wrong with the SlimFit3 LX. It’s well-built, durable, and offers a decent level of performance, comfort, and safety.

Graco SlimFit3 LX Install in Vehicle

3. Value for Money

Is the price tag worth it?

The SlimFit3 LX has a lot going for it. As well to good looks, it has the performance to ride the kids comfortably and safely in the car.

However, for all that it has going in its favor, other car seats in its price class give it a ride for its money.

This is because the SlimFit3 LX shares its price tag with all-in-one scooters that have higher weight and height limits. 

However, if we solely focus on the compatibility to fit three across, it has very few competitors to live up to.

The True3Fit LX is one from the same company but seems not available on market right now – it’s supposed that the Slim3Fit LX replaces True3Fit LX with the same features to satisfy the needs of fitting-3-across. 

The other slim car seats from Diono. The Raidan 3-series is guessed to be the first car seat to fit 3 across. 

But considering its slim design, along with the three–seat-stage riding ability and a few advanced improvements, the Graco SlimiFit3 LX is still a good choice for big families or families with small cars.

Graco SlimFit3 LX vs SlimFit

Car Seats Comparison Graco SlimFit3 LX Graco SlimFit3
Modes of Use 3 modes of use from 5-100 lb 3 modes of use from 5-100 lb
Fits 3 Car Seats Across -
10-Position No-Rethread Harness and Headrest
4-Position Recline
Push-Button InRight LATCH
Breathable AirFlow Mesh Channels -
Rapid Remove Cover -
Integrated Belt Lock-Off for Easy Installation -
Width 16.7 inches 18.5 inches

4. Design

Dimension and Width

You can find the SlimFit3 is a very narrow car seat at first glance, even if you don’t know its specific dimensions. 

To achieve the objective to fit 3 across in the back seat, the company designed the SlimFit3 with a very slender body.

The real dimensions for Graco SlimFit 3 LX are 16.75 (W) X 24.5 (H) X 20.7 (D) inches, at a weight of 19.2 pounds.

So, even the car seat is slim, but not lightweight to carry and switch between vehicles.

The 16.7-inch width is even narrower than the 17-inch width of Diono Radian 3R, which designs and manufactures the first classic 3-across-fitting car seats. But this gap can be ignored as these two car seats perform well to take up less space in the back seat.

The depth and height of the SlimFit3 LX are quite similar to other Graco car seats, just a little bit higher, for instance, 4Ever DLX’s 24-inch height versus the 24.5-inch height of SlimFit3 LX.

The narrow body also gives you the illusion that the latter is much longer than the others.


Even if the Graco SlimFit3 LX seems like a skinny thing, it will not get a high score in portability. We rate it at 7.5, better than 4Ever DLX, for its lighter weight, only 19.2 pounds. 

This weight is very rare among all-in-one car seats, even the Diona Radian 3R weighs up to 25.9 pounds in total. 

But this does not mean the Graco SlimFit 3 LX is as portable as Diona Radian 3R. Actually, the latter is more portable, for its folding design. The bottom seat pad can be folded and attached to the back support for easy carrying from one place to another.

The Graco SlimFit3 LX does not feature a foldable design. That’s why you’ll receive a large packing box. The car seat is 99% assembled before shipping, and you only need to attach a few small accessories, like cup holders.

Seldom car seats can be folded for portability consideration. As far as we know, Diona Radian 3R is one, the other should be the Doona infant car seats. 

The manufacturers might not take the portability into consideration because most families would purchase at least two car seats to be placed in the different vehicles. 

However, portability is a good point if you want to take your baby on an air-flying trip with you. As a result, a few accessories like the car seat carrier come out.

Two Cup Holders for Graco SlimFit 3 LX

Cup holders seem to be the essential accessories in Graco’s car seats. You’ll see that there is at least one cup holder for every car seat, on the right side. 

This is very convenient for both kids and parents. Cup holders are used to holding drinks and snacks.

Unlike the square cupholders on Extend2Fit, the SlimFit3 LX comes with two circular cup holders on both sides. 

They are big enough to hold most water bottles for kids and adults.

This is a huge improvement from square cup holders. Parents sit back aside and the kids can put their drinks in the cup holders as well.

They can be easily attached to the car seat on both sides, within your kid’s touch.

How to install and remove cup holders on SlimFit3 LX?

There are two attachment points on both sides. You can easily insert the cup holder into either of the cup holder attachment points.

If installed successfully, you will hear a “CLICK” when they are secured in place. 

To remove the cup holders from the car seat, you just need to push the release button on the side of the seat and remove the cupholder.

The SlimFit3 LX cup holders are dishwasher-safe with the mode of Top Rack Only.

If you find the cup holders are interfering with installing the seats side-by-side, you can remove the cup holder from one of the seats for a better fit.

This can be very useful if you need to install up to three car seats in the back seat.

Headrest and Harness

The headrest in the car seat is used to hold and protect the kid’s head. 

It’s commonly made of breathable fabrics to keep your child comfortable in the car seat.

The padding inside offers two layers of side impact protection that helps avoid sudden shockness for any crashes. 

The SlimFit3 LX was designed with the Graco no-rethread Simple Safe Adjust (SSA) harness system, which allows you to adjust the height of the harness and headrest in one motion at the same time. 

Even though it’s a common feature in all the car seats on the market – different car seat brands may have different sayings, it helps a lot, especially if the car seat has more than a 10-position headrest. 

It seems that Graco has a default setting on headrest positions. The 10-position headrest can be found on all Graco all-in-one and convertible car seats. 

That’s a great feature to grow with your child.


Reclines are commonly used to adjust your kid in a perfect position for the greatest comfort.

It’s a pity that the Graco SlimFit3 LX only features 4 reclines, two less than 4Ever DLX.

Two (1st and 2nd) for rear-facing and two (3rd and 4th) for forward-facing (including booster).

Graco SlimFit3 Reclines

How to find a proper fit recline angle?

The base recline handle is under the seat pad and is used for adjusting the recline position for the perfect fit for growing children.

You can easily adjust it by pulling out on the handle to adjust to one of the four positions.

The first two positions from 1 to 2 are for rear-facing only and they’re in blue color.

The third and fourth positions indicate both forward-facing and booster mode. 

It does not specify the weight requirement as Graco 4Ever DLX.

The user manual does not provide this information, but just three car seat states – rear-facing (1st & 2nd), forward-facing (3rd & 4th), and booster (4th).

Infant Head and Body Support

To help small babies and infants fit safely and comfortably in the car seat, the SlimFit3 LX includes the head and body inserts. 

The head support not just gives extra assistance to keep your baby’s head stable, but also helps avoid their head shaking from side to side after they’re asleep.

It’s also adjustable along with harness straps, just slide it into the opening in the headrest. 

The body support is also friendly for small babies and infants. It is used to raise the little passengers up to allow the harness to be installed correctly and tightly enough for security.

Both the head and body support can be removable when the infants grow bigger.

5. Performance

3-Across Fitting

The design to fit three across makes the SlimFit3 LX beat the most all-in-one car seats on the market.

Its narrow body earns a great deal of praise among big families who have several kids to ride in the car seat.

However, you should never place the car seat overlap with other car seats, avoiding any loose and incorrect installation.

We’ll talk about more details of fitting 3-across in the installation part.

Graco SlimFit3 X Fit 3 Across

Graco SlimFit3 LX Weight and Height Limits

From its specifications, the Graco SlimFit3 LX is capable of riding a newborn baby as small as 5 pounds.

It’s not as low as the pounds of Graco 4Ever DLX and Extend2Fit, but still great for most babies after their births. 

If the newborns are too small to fit well in the car seat, there is a baby insert.

What’s the rear-facing top weight limit? The SlimFit3 LX allows a baby as heavy as 40 pounds to face the rear.

As long as your infant approaches this weight limit, it’s time to turn the car seat to face forward, probably around 2 years old.

The 40-pound weight limit is the only deciding factor that determines the car seat’s orientation because the SlimFit3 LX allows up to a 49-inch top height limit for rear-facing.

As a result, it’s common for toddlers to reach the 40-pound weight limit first before they grow to 49-inch tall. 

This 49-inch rear-facing height limit is not listed in the product description, but you can find it in the SlimFit3 LX user manual

The weight and height limits for forward-facing with a 5-point harness are quite common as other forward-facing car seats: from 22 lbs to 65 lbs in weight and up to 49-inch in height.

That means, your child can ride with the 5-point harness protection until their preschool times, typically around 5 years of age.

Moving to the booster mode, the weight and height limits of SlimFit3 LX are as good as most booster seats.

The weight requirement for a kid is 40 pounds or more but less than 100 pounds, along with a top height requirement of 57 inches.

Besides the weight and height requirements, all booster seats also add a minimum age condition – the little passenger should be at least 4 years old to ride in a booster according to the car seat laws in the United States.

Age Range

Graco SlimFit3 LX is an ultra-performance all-in-one car seat. Naturally, it was designed to last for a long time so that your child can ride in this car seat from their birth to tween.

The combination of a 100-pound top weight limit and a 57-inch top height limit is supposed to fit most kids around 8-10 years.

That would be good enough for the legal age/weight/height to get out of the car seats in all US states by the laws – typically 8 years of age.

To match its weight/height and age range, the SlimFit3 LX was manufactured with a long lifespan of 10 years.

That’s the longest life allowed for a car seat.


As an all-in-one car seat, the SlimFit3 LX is certainly capable of riding through car seat stages (based on the definition of NHTSA) – rear-facing, forward-facing, and booster. 

It combines three car seat types into one – infant, convertible, and booster, starting from a child’s birth and ending at a child’s preteen.


Is a Graco SlimFit3 LX all-in-one car seat allowed on planes?

Absolutely yes.

This Graco SlimFit3 LX is certified for use in aircraft, but you should use it only on forward-facing airplane seats, with the internal harness system for installation.

This is because forward-facing is the only position allowed on a plane.

The seat belt is the only way to install the car seat on an airplane. No LATCH connectors in the aircraft seats. 

But the car seat can be placed in both rear- and forward-facing positions. You need to follow the instructions for vehicle installation with Lap Belt.

It is NOT allowed to be used in booster mode on the aircraft, because aircraft do not have shoulder belts, which is required to install a booster seat.

It’s STRONGLY recommended to call the airline to make sure this car seat can be installed on their planes before onboarding.


How long is a Graco SlimFit3 LX car seat good for

Up to 10 years of time from its manufacturer date. 

The Graco SlimFit3 LX has a lifespan of 10 years of usage. That’s the longest of the car seats.

Most all-in-one or convertible car seats are manufactured to last so long to grow with your kid. 

However, you may not use the SlimFit3 LX for 10 years. That’s not in real life.

The 10-year of lifespan starts from the date it was manufactured – You can find the sticker on the back of the car seat, not the day you purchase the car seat.

However, that should be long enough to ride your child until they are large enough to use the seat belt.

8-year-old is the most common age requirement in most state car seat laws that no need to travel in a car seat.

If your child grows slower than their peers, a cheaper backless car seat is also a good option if the car seat is expired.

Further Information:

When do Graco car seats expire?

6. Crash Tests and Safety Ratings

The SlimFit3 LX might be one of the safest car seats from Graco, thanks to its inherited Graco ProtectPlus Engineered feature.

The company boasts of this patented protection function to protect your child all-sided: frontal, side, rear, and rollover. 

It’s a real case that the car seats sold on the US market are required to pass the most rigorous crash tests and standards from the US and Europe before going to market for sale.

So it’s understandable that Graco SlimFit3 LX meets or exceeds the child restraint criteria for a frontal crash test under the US FMVSS 213

Side-impact protection should be tested for occupant retention with the built-in 5-point harness system.

This test must be done for all the car seats with a 5-point harness.

That’s why the child safety seat laws ask the parents to ride toddlers and babies in a 5-point harness for as long as possible. 

And you’ll see a few booster seats featuring the 5-point harness as a bonus to extend its wide use.

Furthermore, the Graco SlimFit3 LX is also tested and approved by EU crash test standards.

Its rear-impact was tested based on the European Rear-Impact Crash Pulses and tested to Graco’s RollSafe™ testing standard based on the European rollover testing procedure.

The all-around crash tests earn this car seat a high safety rating in protection performance.


The Graco SlimFit 3 LX does not specify its warranty on the user manual.

Its warranty is in accordance with the limited warranty of all the Graco products.

Typically, the warranty is at least 12 months for the major parts, but the manufacturer does not make this clear.

7. Installation

Read Graco SlimFit 3 LX Manual

It’s important to follow instructions in the user manual to install and use the Graco SlimFit3 LX 3-in-1 car seats. 

It’s usually included in the package, but you can always find the online user manual on its official website, or download the PDF manual here

Sometimes, words are less powerful and clear to explain the usage and installation than the videos.

More than the introduction videos from the Graco company, there are plenty of YouTube videos uploaded by parents and you can search for any type of solution because the Graco SlimFit3 LX is really a popular model.

Which Installation Method Should I Use?

This car seat can be installed in your vehicle using either the vehicle seat belt or the LATCH system. Both ways are equally safe to ride your child as long as you install it properly following the Graco Graco SlimFit 3 LX user manual. It’s NOT allowed to use both methods at the same time.

Rear-facing Installation

Here is the video tutorial to install the Graco SlimFit3 LX in a rear-facing position. Follow this guide along with the user manual.

Intall Graco SlimFit3 LX with LATCH
Install Graco SlimFit3 LX with vehicle seat belt

Forward-facing Installation

Install Graco SlimFit3 LX Forward-facing with LATCH
Install Graco SlimFit3 LX Forward-facing with vehicle seat belt

Do More to Ensure Your Child's Safety

Checklist if everything is ok
  • Car Seat Does Not Move More than 1” (2.5 cm) at the Belt Path
  • Harness Straps at or Just Below the Child’s Shoulders
  • Chest Clip Even With Armpits
  • Cannot Pinch Harness Straps at the Shoulder
How to secure your child with a 5-piont harness?

1. Loosen Harness Straps. Push down on the harness release lever while pulling out on the harness straps at the chest clip. Unbuckle the chest clip and the crotch buckle. Place harness straps off to the sides. On select models, place harness straps in buckle storage pockets.

2. Place Your Child in the Seat. Make sure their back is flat against the car seat back. Avoid bulky or heavy clothing. Doing so will prevent the harness straps from being tightened properly. Place a blanket over the child after you have secured the child.

3. Place Harness Straps Over Child’s Shoulders and Buckle. 

You will hear a “click” when buckle tongues are securely attached. Pull up on each buckle tongue to make sure it is securely attached.

4. Be Sure the Harness Straps Are at the Proper Height. Rear-Facing: Harness straps should be at or just below the child’s shoulders. Top of head must be 1” (2.5 cm) below the headrest adjustment lever.

 Forward-Facing: Harness straps should be at or just above the child’s shoulders. Top of child’s ears below top of headrest.

5. To Raise or Lower Headrest/ Harness Height. Squeeze the adjustment handle and move headrest for the proper harness height.

6. Check the Buckle Position. The correct slot is the one that is

closest to your child without being underneath them. The crotch strap must be in the front most slot when forward facing.

7. To Adjust Crotch Strap. Recline the car seat and locate the metal retainer under the car seat shell.

8. Rotate Metal Retainer and Insert It Up Through the Shelland Pad. 

From the top of the car seat, pull the crotch buckle out.

9. Insert Metal Retainer in the New Crotch Buckle Slot. Reach underneath the car seat and pull the metal retainer through. The crotch strap must be in the frontmost slot when forward facing.

10. Pull Up on Crotch Strap to Make Sure it is Secured

11. Buckle the Chest Clip. You will hear a “click” when the chest clip is securely buckled.

12. Pull All the Slack Out From Around the Waist. Pull up on the harness strap while pushing the chest clip down. Do this to both sides.

13. Tighten the Harness by Pulling the Harness Adjustment Strap. When you are not able to pinch any of the harness webbing at your child’s shoulder, the harness is tight enough.

A snug harness should not allow any slack. It lies in a relatively straight line without sagging. It does not press on the child’s flesh or push the child’s body into an unnatural position.

14. Raise the Chest Clip to Child’s Armpit Level

Booster Installation for Graco SlimFit3 LX

1. Raise the headrest to the highest position

Squeeze the height adjust lever and lift the headrest to the highest position.

2. Store the Harness

A. Loosen the harness straps.

B. Unbuckle the chest clip.

C. Unbuckle the buckle.

D. Remove harness covers and store for future use.

E. Lift the headrest pad flap up out of the way.

F. Open the harness storage door. You’ll heard ‘CLICK!’

G. Place chest clip and buckle tongues inside Storage Compartment and close the door.

H. Store buckle inside the pocket in the car seat shell as shown. Move the buckle to the rear slot when storing.

I. Replace Seat Pad.

Move the headrest back to its proper position for your child.

3. Recline the Car Seat

Pull out the recline handle and place the car seat in 4th recline position.

4. Place Car Seat Forward-Facing in Back Seat of the Vehicle

Place forward-facing in vehicle seat. The base should sit as flat as possible on the vehicle seat.

The front of booster seat MUST NOT hang over front of vehicle seat.

***Skip to Step 11 if Not Using LATCH

5. Make Sure Lower Anchor Strap is in the Forward-Facing Belt Path Marked with Orange Label

Continue to next step if correct. See section 8 if it is not.

6. Unhook Tether Strap From Storage Location and Lay it in the Seat

7. Connect Lower Anchor Connectors to Vehicle’s Lower Anchors

Lower Anchor Strap should not be twisted. If twisted, you will not be able to tighten the strap. Make sure that the arrows are pointing up.

8. Remove The Slack From The Lower Anchor Strap

9. Attach Tether Strap

Extend the tether by lifting up on the tether lock and attach. Consult vehicle’s owner manual for specific location.

10. Tighten Tether Strap. Remove all the slack.

11. Thread the Vehicle Seat Shoulder Belt Through Seat Belt Guide on the Headrest

Advanced tips to make sure booster installation is correct
  • Never Use Lap Belt Only
  • Lap Belt Behind Armrest and Lies Low Across
  • Hips and Thighs
  • Shoulder Belt Lies On the Shoulder, Between
  • the Neck and Edge of Shoulder

8. Specifications







Suitable for

Newborns, toddlers, and preschoolers


Rear-facing and forward-facing



Portability (1-10)

7.5; Slim but a bit heavy

Weight (lb.)


Weight limits (lb.)

5-40 for rear-facing, and 22-65 for 5-point harness, 40-100 for highback booster

Height limit (inch)

49” for rear-facing and forward-facing, 57” for booster


16.7 (W) X 24.5 (H) X 20.7 (D)  in.

Cup holder

Two on both sides



Age Range

0-10 years old


1st, 2nd, 3rd


0-10 years old


LATCH and seat belt

Headrest Positions


Recline Positions





10 Years

Extra Features

Fit 3 across, Rapid Remove pad, AirFlow materials

9. Alternatives

In this section, we’ll compare the Graco SlimFit 3 LX with other car seats to find its positive and negative points.

The first one is the Evenflo Revolve360 Slim with Quick Clean Cover (QCC for short on our website). It was designed with the same slimmest width at 16.75″, being a great 3 across car seat as well. However, it’s a 2-in-1 convertible car seat, meaning it has lower weight and height limits.

The better point compared Evenflo Revolve 360 Slim to Graco SlimFit 3 LX is the 360-degree rotation. Yes, the Revolve360 Slim with QCC is a rotating car seat.

The other alternative is a 3-in-1 car seat. Diono Radian 3R and its premium siblings feature the same 17-inch width – a bit wider than SlimFit 3 LX’s 16.75″. 

What other car seats should you consider?

Evenflo Revolve 360 Slim Swivel Convertible Car Seat

Evenflo Revolve360 Slim with QCC

Why is it better than the Graco SlimFit3 LX?
Why its worse than the Graco SlimFit3 LX?
Diono Radian 3R 3-in-1 Car Seat

Diono Radian 3R

Why is it better than the Graco SlimFit3 LX?
Why its worse than the Graco SlimFit3 LX?