Best All in One Car Seat with Safest Ratings for Infants, Toddlers, and Big Kids

If you’re looking for the best all-in-one car seat that will last long throughout your child’s birth to preteen, you’ve come to the right place. These all-in-one car seats are comfortably cushioned, masterfully crafted, and individually styled to most parents’ tastes.

From its name, you may find there are many 3-in-1 or 4-in-1 car seats. However, some may not support the first rear-facing stage, some may not have the backless mode.

To help you distinguish the real 3-in-1 and 4-in-1, we write this ultimate guide for your reference.

All-in-one car seats are considered a great money saver. With an all-in-one car seat, you don’t need to buy an infant car seat (but you may need a stroller), a convertible car seat, or a booster. It combines them all into one!

Most all-in-one car seats are actually 3-in-1. Some are even better! They’re 4-in-1 car seats that include a backless mode, like the Graco 4Ever DLX 4-in-1.

So we categorize all-in-one car seats into two groups: 3-in-1 (including rear-facing, forward-facing, and highback booster) for group 1 and 4-in-1 (3-in-1 and backless booster) for group 2.

You can click the below button to view the best 3-in-1 car seats and best 4-in-1 car seats.

4 in 1

All in one car seats with backless

3-in-1

All in one car seats

4-in-1? Or 3-in-1

All in one car seats with boasted 4 in 1

We also rank the all-in-one car seats with their performance (weight/height limits), price, and bonus features like a narrow design to fit 3 across.

By Weight Limit

See Our Top Picks Organized by Size Limits from up to 120 lb

By Height Limit

Best Choices Organized by Height Limits from up to 63 inches

By Price

See Car Seats Organized by Price (Prices Start at $179.99)

By Bonus

See Car Seats by Bonus features (e.g. fit 3 across etc)

Best All-in-one Car Seats - 4-in-1

Graco 4Ever DLX – Best 4-in-1 Car Seat for Overall

Graco 4Ever DLX 4-in-1 Car Seat

Graco 4Ever DLX

Key Features
The Good
The Bad

$329.99

Graco 4Ever DLX is a real 4-in-1 car seat and it’s the first and best recommendation for you. Designed to grow with your child, the 4Ever DLX last three car seat stages: rear-facing, forward-facing, and booster (the last one is a seat belt based on NHTSA’s definition). 

It’s good for newborns as light as 4 pounds. That means, even preemies can use this 4-in-1 car seat. To accommodate a baby well, the 4Ever DLX heart-warmly includes an infant insert to keep your precious stable in the car seat during trips. 

This 4lbs beats most of the best all-in-one car seats, like the one from the same company – Graco SlimFit3 LX (5lbs), Safety 1st Grow and Go (5lbs), and Maxi Cosi Pria (5lbs).

The 40lbs rear-facing upper weight limit makes Graco 4Ever DLX one great car seat for extended rear facing. It’s 5 pounds more than most infant car seats with a 35 pounds limitation. However, it’s not as good as those with a higher 50-lb rear-facing limit, like the Britax One4Life (5lbs) and Diono Radian 3R (5lbs).

As one of the best 4-in-1 car seats, the Graco features a top booster weight of up to 120 pounds designed for both high-back and no-back modes

Graco 4Ever DLX Installation in Car

The Graco 4Ever DLX 4-in-1 car seat is one of the safest car seats for infants and toddlers. It comes with the company’s safety feature – ProtectPlus engineering, which is applied only in premium models.

Graco car seats that are ProtectPlus engineered to enhance the shielding function. They can perform better to deliver optimal protection from the frontal, side, rear, and rollover if an incident happens.

Some other safety features like the InRight rigid LATCH for easy installation, two layers of side impact protection, reinforced steel-made metal frame and energy absorbing foam are as good as other best all-in-one car seats on this list.

It’s a kid-friendly 4-in-1 car seat. Included infant insert and head support help reduce the swivel for small babies and ensure they do have stable riding in case of any bumps. The cup holders are welcome for toddlers who will have their snacks and drinks stored there.

It’s also a parent-friendly 4-in-1 car seat. Made of machine washable fabrics, the 4Ever DLX is easy to clean. 

What we love most is the newly upgraded feature – Rapid Remove Cover (which can be found in the Graco SlimFi3 LX as well). You can quickly get the seat cover off the car seat and throw it into the washing machine.

Compared to its siblings, Graco 4Ever DLX  4-in-1 convertible car seat has other excellent improvements. 

The Graco 4Ever DLX has a belt lock-off that makes it easier for a vehicle seatbelt installation. This works like the ClickTight for Britax One4Life.

Evenflo EveryFit - Best Budget 4-in-1 Car Seat under $200

Evenflo EveryFit 4-in-1 Car Seat for Girls

Evenflo EveryFit

Key Features
The Good
The Bad

$199.99

If you’re fond of a US-made toddler all-in-one car seat, the Evenflo EveryFit is a good option. It’s the cheapest 4-in-1 car seat, with a low price of under $200. 

Unlike other promoted 4-in-1 car seats that are real 3-in-1 for the first three stages (rear-facing, forward-facing, and booster), the EveryFit is a real 4-in-1 car seat with no back mode. This makes it perform as well as the Graco 4Ever DLX (120lbs/57” for booster, 65lbs/49” for forward-facing, 40lbs/49” for rear-facing).

Then why do their prices vary a lot? The Evenflo EveryFit lacks a few premium features that Graco 4Ever DLX has.

Evenflo EveryFit has basic safety features. It’s good for meeting all applicable federal safety standards that are mandatory for car seats. It also features advanced side impact protection. It even passes the rollover tests for proving itself to be a good car seat to protect your little one in case of any rollover collisions. 

Graco 4Ever DLX has all of these safety features and more. It’s ProtectPlus engineered to be protective from frontal, rear, side, and rollover in crashes.

Even if it’s abnormal for a car to have any crash potentiality from the front. The rear and both directions provide a buffer for reducing the crash energy for a car seat and the baby in the car seat.

Evenflo boasts the EveryFit all-in-one car seat for its airflow mesh fabrics to deliver the max comfort for your little one. That adds a positive point for this 4-in-1 car seat, especially if you’re living or planning to travel in hot cities. The airflow mesh fabrics keep your child cool in the EveryFit 4-in-1 car seat, avoiding them getting sweaty on hot summer days.

It’s a pity that this 4-in-1 car seat does not provide a fast way to remove the seat cover/pad. It’s beaten by the Graco 4Ever DLX 4-in-1 car seat from this point. The latter features a ‘Rapid Remove cover. Both are made of machine-washable fabrics for easy cleaning.

Best All-in-one Car Seats - 3-in-1

Britax One4Life ClickTight – Best 3-in-1 Car Seat Overall

Britax One4Life ClickTight All-In-One Car Seat

Britax One4Life - Plum

Key Features
The Good
The Bad

$399.99

Britax One4Life is #1 of the best 3-in-1 car seats. We recommend it for its ClickTight feature and its great size limitation, even though it does not have a backless mode.

We know how important a proper installation means for your child’s safety. Most of the car seats will have a rigid LATCH for easy installation. But Britax does it the other way.

The company focuses on improving seat belt installation and launches the ClickTight technique. That moves the installation with a vehicle seat belt to the next step

It’s as easy as using a LATCH. However, installing a car seat with the vehicle seat belt does not have a limit like installing with a LATCH. You may find in the car seat user manual, there is a LATCH weight limit, which is lower than the 5-point harness limit. Actually, it’s equal to the harness limit minus the car seat body weight.

If you should use a seat belt for installing the car seat at last, then choose one that with easy seat-belt installation might be a good idea. That’s why we think you should give the Britax One4Life a try if you’re planning to buy a 3-in-1 car seat.

Britax One4Life ClickTight

This all-in-one car seat has another point we love. It has a great size limit: 120lbs/63”. That’s unbeatable among all the car seats. Even the 4-in-1 car seat – Graco 4Ever can’t beat this. It only supports 120lbs/57” (which is still good for accommodating most kids at eight years old). 

All-in-one car seats are considered as a money saver. That’s true for most cases, for example, other 3-in-1 car seats are priced under $300: Maxi Cosi Pria ($299.99), Graco SlimFit3 LX ($279.99), Safety 1st Grow and Go ($179.99), and Diono Radian 3R ($199.99); even the 4-in-1 car seats like the Evenflo EveryFit is low-priced under $200. 

However, Britax One4Life all-in-one breaks the rule. It costs you almost $400 ($399.99 when the post is published). But considering its great features and easy installation (installing a car seat is really a big challenge for parents), it’s reasonable.

It seems that Britax now only maintains the high-end models with the ClickTight feature, which makes their car seats more expensive than most models on the market. But it’s not the most expensive 3-in-1 car seat, the Diono Radian 3QXT (We’ll talk about it in the next part on a 3R product) is even more expensive with a price up to $450 or so.

Diono Radian 3R – Best All in One Seat for Three Across

Diono Radian 3R 3-in-1 Car Seat

Diono Radian 3R

Key Features
The Good
The Bad

$199.99

If you have several children in a car seat and want to get a budget all-in-one car seat for them, then you can check the Diono Radian 3R. It’s an entry-level 3-in-1 car seat from the Diono company that is well-known for its Radian series car seats. 

All the Radian series car seats feature the same 17-inch width at the hip part. This enables the car seats to fit three across in most vehicles (even in small cars) while still providing enough room for growing kids. 

Priced under $200, the Radian 3R is good for budget-tight families. If you want a cheaper one (only a few bucks cheaper), check the other 3-in-1 car seat – Safety 1st Grow and Go ($179.99 while post written). But the latter one does not fit 3 across. The other 3-in-1 car seat – Graco SlimFit3 LX is narrower (16.75-inch width, $279.99) but it’s a bit more expensive than $199.99.

The budget price does not compromise its size limit. The Diono Radian 3R has a top-ranked rear-facing size: of 50lbs/44” and a booster size: of 120lbs/57”. The 50-lbs rear-facing is as good as Britax One4Life (50lbs) and beats other all-in-one car seats including Graco 4Ever DLX and SlimiFit3 LX, Evenflo EveryFit, Maxi Cosi Pria, Safety 1st Grow and Go, and Chicco Fit4 (40lbs). 

Diono Radian 3R Fit 3 Across

The Diono Radian 3R is a slim design, but it is not a lightweight car seat. It’s even a bit heavy, weighing almost 26 pounds. But it’s one of the most portable car seats. It’s FAA approved to be foldable. You can carry it like a backpack with straps. That means you can easily navigate it through the airports. 

However, this does not mean the Radian 3R is perfect. It lacks the infant insert and head support. That’s not friendly for newborns and small infants, even though it has a 50-lbs rear-facing limit that is good for tall babies to ride rear-facing longer.

It does not provide multiple reclines for parents to find a comfortable angle for growing kids. It’s a really narrow all-in-one car seat, but if being placed rear-facing, the 28.5-inch height of the car seat will take much room from the front driver or passenger if you install it on either side.

You can’t expect a budget 3-in-1 car seat to have all the great features. The rule of what you get for what you pay still works in choosing a car seat.

So if you really like a slim car seat for 3 cross fit with advanced features, you can check the Radian 3R’s siblings – Radian 3RX/ 3RXT, or the higher-end models -Radian 3QX/ 3QXT/ 3QXT Safe+.

The Diono Radian 3R has a superb advantage over other all-in-one car seats. It offers an extendable warranty of up to 36 months (over others’ 12 months) if you register the car seat. All car seats in the Radian series can have this extended warranty.

Car Seats Comparison Radian 3R Radian 3RX Raidan 3RXT Raidan 3QX Radian 3QXT
Price $199 $269 $329 $369 $399
Weight limits (lb) RF:5-50 / FF: 22-120 RF: 5-50 FF: 22-120 RF: 5-50 FF: 22-120 RF: 4-50 FF: 22-120 RF: 4-50 FF: 22-120
Rear Facing Weights Up to 50lb Up to 50lb Up to 50lb Up to 50lb Up to 50lb
Newborn Protection - - 2-in-1 Advanced 3-in-1 Advanced 4-in-1
Safe+ Engineering - - -
Head Support - 12 Positions 12 Positions Safe+ 12 Positions Safe+ 12 Positions
Cup Holder -
Fit 3-across
Width (in.) 17 17 17 17 17

Maxi-Cosi Pria – Most Padding All-in-One Car Seat

Maxi-Cosi Pria All-in-1 Car Seat

Maxi Cosi Pria

Key Features
The Good
The Bad

$299.99

Unlike most car seats on the market that are designed with black and deep gray colors, the Maxi Cosi Pria provides multiple colorful options. If you want an all-in-one that will last a good few years for little girls, bright pink and purple are good options.

The Maxi Cosi Pria seems to have thicker padding than other car seats. The infant insert, headrest, and seat pad, all are decently cushioned with energy-absorbing foam. The lavish padding not only ensures reliable protection but also delivers maximum comfort.

The decent padding should contribute a lot to Pria’s price. Priced almost $300, the Maxi Cosi Pria comes with average size limits: 40lbs/40” for rear-facing; 65lbs/49” for forward-facing; and 100lbs/52” for booster.

Maxi Cosi Pria Harness Holders

The 52-inch booster height limit is easily defeated by other all-in-one car seats with 57-inch top booster height, like the Graco 4Ever DLX and SlimFit3 LX, Diono Radian 3R, and Chicco Fit4. Not to mention the 63-inch Britax One4Life.

Only the Safety 1st Grow and Go has the same 52-inch top booster height. Both come from the same company – Dorel Julivence, with very basic safety features. But the Grow and Go is more than $100 cheaper than the Pria.

The colorful seat cover also inspires the Maxi Cosi Pria slightly high priced at around $300. This makes the Pria 3-in-1 car seat look high-end. Plus, parents don’t have many bright color options for girls.

So we have two posts that list a few great pink car seats and a few purple car seats. Both have included Maxi Cosi Pria pink and purple.

Graco SlimFit3 LX - Narrowest all in one car seat

Graco SlimFit LX 3-in-1 Car Seat

Graco SlimFit3 LX

Key Features
The Good
The Bad

$279.99

You won’t believe this – The Graco SlimFit3 LX (16.75-inch) is narrower than the Diono Radian 3R (17-inch). It’s the narrowest all-in-one car seat on this list. The 16.75-inch width is unbeatable among the convertible and all-in-one car seats because most of them are really bulky.

Maybe the Graco company was spurred by the Diono Radian series for fitting 3 across in the back seat. At first, it launched the SlimFit3 which is also as narrow as 18.5-inch. But this width does not fit well in small cars for three across fit. As a result, its slimmer sibling – SlimFit3 LX came out. 

It seems Graco benchmarked the SlimFit3 LX to the Diono Radian series and strived to beat them. However, the slight difference between a 16.75-inch SlimFit3 LX and a 17-inch Diono Radian car seat can be disregarded if you look at them both. 

Graco SlimFit3 X Fit 3 Across

Measuring 16.75-inch in width, the SlimFit3 LX is absolutely a narrow car seat to fit 3 across.

The Graco SlimFit3 LX is also an affordable 3-in-1 car seat. Priced under $300, it’s not as expensive as the Graco 4Ever DLX ($329.99), Chicco Fit4 ($379.99), and Britax One4Life ($399.99), but it’s neither as cheap as the Safety 1st Grow and Go ($179.99), and Evenflo EveryFit ($199.99).

The SlimFit3 LX is one of the safest car seats for your boy or girl. As a premium and primary model from Graco company, the SlimFit3 LX features the ProtectPlus engineering that will protect your child from frontal, side, rear, and rollover in case of any incidents.

This 3-in-1 car seat is friendly for parents. Made of machine washable fabrics, you don’t need to waste the time washing it by hand but can save time to play with your precious. More than that, it features an impressive ‘Rapid Remove cover’, which is used in Graco 4Ever DLX as well. 

Taking the seat cover off might be one of the big challenges – the other should be the car seat installation. We always love the one with this convenient design, like the Chicco NextFit Zip and its premium siblings.

Safety 1st Grow and Go - Best Budget All-in-One Car Seat

Safety 1st Grow and Go All-in-One Car Seat

Safety 1st Grow and Go

Key Features
The Good
The Bad

$179.99

The Safety 1st Grow and Go is a real money saver. It’s a 3-in-1 car seat that lasts a good few years when your child is 6 or 7 years old. It’s priced under $200, even cheaper than the Diono Radian 3R. It’s the cheapest all-in-one car seat on this list.

This is another 3-in-1 car seat the low price does not compromise the size limit. The Safety 1st Grow and Go is more than $100 cheaper than the Maxi Cosi Pria, but it has the same size limits as the latter one: rear-facing (40lbs/40”), forward-facing (65lbs/49”), and booster (100lbs/52”).

You may have found that the top booster weight (52”) is a bit lower than others, like the Graco 4Ever DLX (57”) and SlimFit3 LX (57”), and Britax One4Life (63”).

As an entry-level 3-in-1 car seat, the Safety 1st Grow and Go has the very basic safety features that meet the federal safety standards. This is very commonly seen in budget car seats.

The Safety 1st Grow and Go seems to have plenty of padding to ensure your child’s comfort in the car seat.

Fake 4-in-1 Car Seats Are really 3-in-1

Chicco Fit4 4-In-1 Convertible Car Seat

Chicco Fit4 4-in-1 Car Seat

Chicco Fit4 4-in-1

Key Features
The Good
The Bad

$379.99

Don’t be treated by the 4-in-1 in the title! The Chicco Fit4 is not a real 4-in-1 car seat (no backless mode from a more accurate differentiation). The Chicco company divides the rear-facing into two with a separate infant (4-16 lbs ) and a separate toddler (12-40lbs). 

A few other 4-in-1 car seats play word games like Chicco Fit4. They can’t be transitioned from a high-back booster to a no-back booster. If we consider the toddler age to be a separate stage, then all the other 3-in-1 car seats on this list should be 4-in-1. All of them have a 40-lbs or 50-lbs weight limit for extending rear-facing toddlers.

As an expensive car seat over $350 on Amazon, the Chicco Fit4 is less popular compared to Graco 4Ever DLX and Britax One4Life.

It does not offer great safety features like the other two premium models above mentioned as well. The Chicco boasts of its ‘DuoGuard’ for head and torso. This is another saying for two layers of side impact protection, which most of the car seats have (except Britax Marathon with one layer only).

It does not even have the great zip-off feature in Chicco’s other models like the NextFit Zip and its premium siblings. I think most moms would love this feature to effortlessly take the seat cover off for easy cleaning.

Like other Chicco car seats, the Fit4 all-in-one car seat comes with the SuperCinch for easy installation. That should be friendly parents to install the car seat properly and tightly for a safe ride. 

I guess the ergonomic design contributes a lot to the expensive price of the Chicco Fit4. It’s decently padded with a few additional available, like the infant insert for newborns. 

It’s not a slim car seat, even though the advertising boasts an image of fitting 3 across. Measuring 19-inch in width, the Chicco Fit4 is not good for three across. You may find that you should fold the cupholders up on both sides to achieve this. This is not friendly for toddlers who want to store drinks or snacks or toys in the cup holders.

All In One Car Seats Comparisons: 4 in 1 vs 3 in 1 vs Fake 4 in 1

Car Seat Rear-facing Forward-facing High-back Booster Backless Booster
Graco 4Ever DLX 4-in-1 4-40 lb. / 49" 22-65 lb. / 49" 40-120 lb. / 57" 40-120 lb. / 57"
Evenflo EveryFit 4-in-1 4-40 lb. / 40" 22-65 lb. / 49" 40-120 lb. / 57" 40-120 lb. / 57"
Britax One4Life 5-50 lb. / 49" 20-65 lb. / 49" 40-120 lb. / 63" -
Diono Radian 3R 5-50 lb. / 44" 22-65 lb. / 49" 40-100 lb. / 57" -
Maxi Cosi Pria 5-40 lb. / 40" 22-65 lb. / 49" 40-100 lb. / 52" -
Graco SlimFit3 LX 5-40 lb. / 49" 22-65 lb. / 49" 40-100 lb. / 57" -
Safety 1st Grow and Go 5-40 lb. / 49" 22-65 lb. / 49" 40-100 lb. / 52" -
Chicco Fit4 4-in-1 4-40 lb. / 49" 22-65 lb. / 49" 40-100 lb. / 57" -

Best All-in-one Car Seats by Size Limits

By Weight​ and Height Limits

Car Seat Weight Limit Height Limit Price Range
Maxi Cosi Pria 100 pounds 52 inches $299.99
Safety 1st Grow and Go 100 pounds 52 inches $179.99
Diono Radian 3R 100 pounds 57 inches $199.99
Chicco Fit4 4-in-1 100 pounds 57 inches $379.99
Graco SlimFit3 LX 100 pounds 57 inches $279.99
Graco 4Ever DLX 4-in-1 120 pounds 57 inches $329.99
Evenflo EveryFit 4-in-1 120 pounds 57 inches $199.99
Britax One4Life 120 pounds 63 inches $399.99

Best All-in-one Car Seats by Prices from $179.99

Rank Price Range Car Seat Weight Limit Height Limit
1 $179.99 Safety 1st Grow and Go 100 pounds 52 inches
2 $199.99 Diono Radian 3R 100 pounds 57 inches
3 $199.99 Evenflo EveryFit 4-in-1 120 pounds 57 inches
4 $279.99 Graco SlimFit3 LX 100 pounds 57 inches
5 $299.99 Maxi Cosi Pria 100 pounds 52 inches
6 $329.99 Graco 4Ever DLX 4-in-1 120 pounds 57 inches
7 $379.99 Chicco Fit4 4-in-1 100 pounds 57 inches
8 $399.99 Britax One4Life 120 pounds 63 inches

Best All-in-one Car Seats by Bonus

Cheapest:

Lightweight

Best for Travel

Three Across Fit

5-point car seat up to 120 pounds

Buyer’s Guide for the Best All-in-One Car Seats

Safety

Safety is always the #1 concern for all parents when choosing a car seat.

You don’t need to worry much about this factor because all the car seats sold in the US have passed the mandatory crash tests to meet federal safety standards. 

You get what you pay for; this rule applies in purchasing a car seat. 

Budget all-in-one car seats ensure the very basic but necessary protection. High-end car seats with premium safety features may be more expensive. My advice to you is to get the best protection that you can afford.

Size Limits

Size limits should match your child’s size.

You won’t want to waste money on a car seat that can’t accommodate your boy or girl well. All-in-one car seats have great size limits, including the rear-facing size limits for extended rear-facing mode

They are designed to grow with your child from day one to the day when your little one doesn’t need a car seat. 

They are not cheap (some models are really cheap like the Safety 1st Grow and Go, Evenflo EveryFit, and Diono Radian 3R). Considering their long use time, you may not need to purchase another car seat and save some money.

Install

Proper installation decides your child’s safety in the car seat. All-in-one car seats with easy installation are preferable.

Remember that most car seats can be installed with the LATCH and seat belts with the former are thought to be an easier way to install a car seat. 

However, Britax offers a very different direction. It launched the ClickTight technique for you to install their car seats with a vehicle seat belt effortlessly. This technology moves the car-seat-installation to the next level.

Fabric

Fabrics mean a lot. It affects how comfortable your little boy or girl stays in the car seat. It decides how easily parents can deal with the car seat. 

No chemical smells in the fabric do not only mean health but also comfort. Machine washable fabrics save you time and let you have more time to play with your precious.

Is an all-in-one car seat good?

The all-in-one car seat is a great choice for those who want to save money in the long run. They can be used for protecting your little one from day one to eight years old when they don’t need a car seat. Some may last longer to your kid’s 9 or 10 years of age, like the Britax One4Life (with high size limits:120lbs/63”).

If you prefer an all-in-one car seat with no back mode, the Graco 4Ever DLX and Evenflo EveryFit are good options. They are real 4-in-1 car seats that can be smoothly transitioned from a high-back booster to backless mode.

What is the best 2022 car seat to buy?

FAQs about Best All-in-one Car Seats

What is the safest all-in-one car seat?

Britax One4Life ClickTight should be the safest all-in-one car seat. The ClickTight feature allows parents to install this car seat properly and tightly for optimal protection. 

It also has a few other safety features like two layers of side impact protection, a reinforced steel frame, energy-absorbing foam, etc.

Are all in one car seats worth it?

Absolutely. An all-in-one car seat works from your kid’s birth to the day when they’re ready to get out of the car seat. That means you don’t need to purchase another car seat if it’s in good condition and never meets any incidents.

What is the best 4 in 1 car seat?

The best 4-in-1 car seat should be the Graco 4Ever DLX 4-in-1 convertible car seat. It’s a bit pricey, over $300 on Amazon. But you’ll find it worthwhile.

It’s the safest 4-in-1 car seat. Featuring the ProtectPlus engineering technique, the Graco 4Ever DLX is protective from frontal, rear, side, and rollover if a crash happens.

Which car seats didn’t make it on the Best All-In-One Car Seats list?

We have listed a few best all-in-one car seats in this post. There are a few models not ranked on this list because they are siblings of one of the best all-in-one car seats on the list. For example, Graco has many great all-in-one car seats with different techniques, but we just take the Graco 4Ever DLX as an example. 

Diono launched the Radian series with all of them being all-in-one car seats. The Diono Radian 3R is the entry-level model with the cheapest price.

We do not list its premium siblings like the Radian 3RX/ 3RXT and another higher-end line including Radian 3QX/3QXT/3QXT Safe+ but do car seats comparison for this series.

What is the expiration date for all-in-one car seats?

Typically, all-in-one car seats expire 10 years after the date of manufacture. They have the longest lifespan. That’s very understandable. After all, they all have high size limits to grow with your child from birth to preteen.

All-in-one car seats from different brands, like Graco, Britax, Chicco, Diono, Maxi Cosi, Safety 1st, Cosco and Evenflo have the same 10-year usable life.

What are the weight limits for these all in 1 car seats?

The weight limits for all in one car seats change from model to model, even some of them may have the same range.

Let’s list the weight limits of all in one car seats below for easy comparison: 

Graco 4Ever DLX (rear-facing: 40lbs; forward-facing:65lbs; booster:120lbs)

Evenflo EveryFit (rear-facing: 40lbs; forward-facing:65lbs; booster:120lbs)

Britax One4Life (rear-facing: 50lbs; forward-facing:65lbs; booster:120lbs)

Diono Radian (rear-facing: 50lbs; forward-facing:65lbs; booster:100lbs)

Maxi Cosi Pria (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

Graco SlimFit3 LX (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

Safety 1st Grow and Go (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

Chicco Fit4 (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

You may find that all-in-one car seats are good for tall babies to stay rear-facing for a longer time.

Can these best all in 1 car seats be considered an infant car seat?

Yes. All in one car seats can be used as an infant car seat for newborns. They are commonly good for newborns weighing between 4 and 5 pounds

With higher size limits than an infant car seat, the all-in-one car seats are suitable to extend rear-facing riding until your child’s age of 2 or 3 years old.

But not all are good for newborns and small infants. Diono Radian 3R lacks infant inserts and supports, which are necessary to keep newborns and small infants stable in the car seat. If you love the Diono Radian car seats for their three across fit, you may choose a premium model, like the Radian 3RX/ 3RXT/ 3QX/ 3QXT.

Do all in one car seats have a slim design to fit three across?

All-in-one car seats are bulky and heavy. That’s right for most of them. Some do have a slim design and can be narrow enough to fit three across.

For example, the Diono Radian 3R and its siblings have a narrow 17-inch width at the seat pad section. So they are all slim to fit three across.

The Graco SlimFit3 LX is another slim all-in-one car seat to fit three across. It’s even narrower (16.75-inch width) than Radian 3R. It’s an upgraded version from the SlimFit3 that was designed with an 18.5-inch width, which is also considered narrow anyway.

Which one of these best all in 1 seats has the best car seat safety features?

When it comes to car seat safety features the Graco 4Ever DLX 4-in-1 Convertible Car Seat takes the lead. Even though all of these all-in-one car seats listed above have high safety standards. 

The Graco 4Ever DLX features the manufacturer’s exclusive ProtectPlus technique. This feature ensures the car seat protects your child from all directions, frontal, rear, side, and even rollover. It passed the European rollover crash test to prove that.

How do you keep your child in the rear-facing position the longest?

If you want to keep your child in the rear-facing position for the longest time, check any of the best all-in-one car seats on the list above. 

They all perform well for an extended rear-facing with higher size limits

Among the best all-in-one car seats, the Britax One4Life and Diono Radian 3R stand out. Both have a 50-lbs rear-facing weight limit that is good enough for extending rear-facing for toddlers between two and four years old.

How do you install these best all-in-one car seats on the back seat?

Follow the car seat product manual to install any car seat in the back, including the all-in-one car seats. 

When installing rear-facing, you should pay attention to choosing the right all-in-one car seat position for the car seat. Those with great product height may not fit well in rear-facing in the back seat. 

For example, the Diono Radian 3R is 28.5 inches high and if you install it rear-facing on either side, it may take much space from the front driver or passenger. 

Another problem is that this all-in-one car seat does not have many reclines. You can’t adjust the recline to accommodate the child in the best fit, and the parents on the front seat won’t be comfortable with little space left.

What kind of features should you look for when buying the best all-in 1 car seat?

Check the advice we listed in the buyer’s guide.

There should be some additional tips for you when you plan to buy the best all-in-one car seat for your little boy or girl. 

Keep in mind to check for side impact protection. All car seats with a 5-point harness would have at least one layer of side impact protection. It’s better if the car seats have two or three or more layers. 

The seat cover and pad should be made of machine washable materials. 

It’s better if the all-in-one car seat has an easy removal seat cover, like the Graco 4Ever DLX and SlimFit3 LX. Both feature the ‘Rapid Remove’ cover. 

Better to have cup holders. Your child should be happy to have his or her snacks and toys stored in the cup holders. It’s a pity that the Diono Radian 3R does not have cup holders. But you are able to purchase another one to attach to it.

The more reclines or headrest positions, the better. As all-in-one car seats are designed to grow with your child, more reclines mean a better fit for your little one at different ages

Better with a backless mode so you don’t need to purchase one. Graco 4Ever DLX and Evenflo EveryFit are good choices.

What would be a good alternative for the best 3 in 1, 4 in 1 and all in one car seat?

On this list of best all in one car seats, we try our best to cover various types of 3 in 1 and 4 in 1 car seats

There are budget models, like the Diono Radian 3R, Safety 1st Grow and Go, and Evenflo EveryFit. All of them are low-priced under $200 (sometimes maybe a few bucks more than $200 due to promotion and stock on Amazon).

There are the safest models, like the Britax One4Life, Graco 4Ever DLX, and SlimFit 3 LX. The former has a ClickTight for easy, proper, and tight installation to ensure safety. The latter two have been tested to deliver protection in any crashes from different directions like frontal, side, rear, and rollover.

There are narrow models, like the Diono Radian 3R and Graco SlimFit3 LX. Both are slim enough to fit three across on the same back row. 

It’s a bit difficult to find a good alternative for all of them. But we don’t think they are perfect anyway. If you have any suggestions for a good alternative for these all-in-one car seats, please let me know and I’ll update this list.

What are the weight limits for the (3 in 1 or 4 in 1) all in one car seats?

All in one car seats last three stages: rear-facing, forward-facing, and booster. The weight limits vary depending on the models. But they are in the same range. To make it clear for you to know the weight limits of the best all-in-one car seats, we list them below for a simple comparison: 

Graco 4Ever DLX (rear-facing: 40lbs; forward-facing:65lbs; booster:120lbs)

Evenflo EveryFit (rear-facing: 40lbs; forward-facing:65lbs; booster:120lbs)

Britax One4Life (rear-facing: 50lbs; forward-facing:65lbs; booster:120lbs)

Diono Radian 3R (rear-facing: 50lbs; forward-facing:65lbs; booster:100lbs)

Maxi Cosi Pria (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

Graco SlimFit3 LX (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

Safety 1st Grow and Go (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

Chicco Fit4 (rear-facing: 40lbs; forward-facing:65lbs; booster:100lbs)

You may find that all-in-one car seats are good to extend rear facing for a longer time.

What makes all in one car seats (all in one seat) comfortable?

Comfortable all-in-one car seats have this in common: they have decent padding. Maxi Cosi Pria stands out.

They have multiple reclines for the best fit for your little boy or girl at different ages. 

They have energy absorbing and memory foam, cup holders (except Diono Radian 3R), adjustable headrest and harness, removable infant insert, body pillow, etc.

Why are Graco car seats so popular?

Graco has the most car seats among the dozens of car seat brands. It has a long history and released a few popular models.

From the product reviews on Amazon, you can know that Graco car seats are more popular among moms and dads than other brands.

The Graco Extend2Fit is the most popular convertible car seat with more than ten thousand of reviews.

The Graco 4Ever DLX 4-in-1 car seat and SlimFit3 LX 3-in-1 car seat are also popular all-in-one car seats for their safety features and different usages.

The Graco 4Ever DLX comes with a backless mode so you don’t need to pay for another backless booster.

The Graco SlimFit3 LX is a narrow car seat to fit three across.

You’ll find the Graco company always takes a step ahead of the trends and manufactures different car seats to meet various needs and situations. 

They keep improving the techniques that can be used for new car seats to replace old models that were outdated.

What’s the difference between an all in one seat and forward facing high back booster seat?

The difference between a forward facing high back booster seat and all in one car seat is the stage, type, and time you use it

High back booster is a booster and lasts for the third stage for big toddlers who are at least 4 years old. The all in one car seats last for three stages (rear-facing, forward-facing, and booster) from birth.

What’s an all in one convertible car seat?

An all-in-one convertible car seat obviously means that it will do all an infant and convertible and booster seats do. It combines three car seats into one and offers rear-facing and forward-facing, throughout the booster.

What is the best all in one car seat?

The best all in one car seat is the Britax One4Life ClickTight All-in-One Convertible Car Seat.

If you are looking for the safest convertible car seats it will be hard to get around the Britax One4Life ClickTight All-in-One Convertible Car Seat. The ten years of lifespan, reinforced-steel frame, V-shaped tether, and SafeCell system make this all-in-one car seat the number one choice in safety features.

Are all in one car seat reviews positive?

The all in one car seat reviews are very positive. They have been tested and proven to be safe for kids of almost all sizes.