Resources Archive

What Is An All-in-One / 3-in-1 / 4-in-1 Carseat?


Graco 4Ever - StudioAll-in-One. 4-in-1. 3-in-1. Does it all. Last carseat you’ll ever need.

These promises sound exciting, don’t they? After all, you’ve probably shelled out over $100, maybe even close to $300 for a rear-facing only infant seat that only fit your child for about a year and now you have to buy another carseat already. Your kid keeps growing, wouldn’t it be nice to buy only one more carseat and be done with it all? Perhaps.

We need to get some basic terms out of the way since I’ll be addressing them frequently in this article. There are two types of carseats we’ll be discussing: convertible and combination. A convertible carseat is one that rear-faces or forward-faces, so it’s appropriate for newborns through preschoolers generally. A combination carseat is a forward-facing only carseat with a harness that can be removed to become a belt-positioning booster. Sometimes combo seats are called harnessed boosters. It’s all marketing, but the official class of seat is combination.

Let’s discuss what an all-in-one / 3-in-1 / 4-in-1 carseat is. These days it can be a convertible carseat or a combination carseat. An all-in-one carseat is one that “does it all.” This convertible carseat will go from infant to booster: rear-facing, forward-facing, and high-back booster. A 3-in-1 carseat does the same: rear-facing, forward-facing, and high-back booster. But a 3-in-1 carseat can also be a combination seat: forward-facing-only harness, high-back booster, and backless booster. Oh. That’s getting complicated. What about the 4-in-1 carseat? Well, that is a convertible carseat: rear-facing, forward-facing, high-back booster, AND backless booster.

What does one of these seats NOT do? It does NOT have a harness weight limit of 100 or 120 lbs. That’s a very common misconception. The carseat manufacturers are doing a much better job of labeling the boxes for their separate modes, but as you look at the pictures below, I think you’ll see why it’s easy to see why the harness might go to a super high weight limit. It doesn’t.

So we have the convertible vs. combination terminology out of the way and we know what an all-in-one vs. a 4-in-1 carseat is (er, basically the same thing, right?). Now let’s have some practice looking at these seats and their boxes so you know in the store *before* you buy if the carseat is appropriate for your 9 month old (of course, you could always consult our Recommended Carseats List and know which seats are appropriate right now and find one that will work for you!).

Questions to Ask Before You Shop

Does it have a rear-facing belt path? (Only if you are shopping for a rear-facing seat obviously.)

How long do I reasonably expect my child to use this seat?

Do I really want a carseat that I will be using for over 6 years? (Because really, what other piece of baby gear gets used for that long, let alone a safety device?)


The Evenflo Symphony LX is an all-in-one seat. It says so on the labels and on the box. Check out the label: 5-110 lbs. That’s misleading, because it makes you think the harness will take your child from 5-110 lbs., right? Wrong. It’s 5-40 lbs. rear-facing, 22-65 lbs. forward-facing, and 40-110 lbs. as a belt-positioning booster. There is a rear-facing belt path opening under where the child’s legs would sit, so you know it’s a convertible carseat. You could use this carseat from your child’s birth, provided he’s big enough.

Symphony LX box front Symphony LX box side


Carseat Comparisons: Measurements and Features Data


Compare Child Restraint Safety Features and Carseat Dimensions

It’s been a very long time in the works, but we’re finally able to make public our database to compare carseat measurements and features, just in time to finish CPS Week, 2015.  The comparison tool uses measurements we take when we review products.  For products we haven’t measured ourselves, we use data contributed by Car-Seat.Org members.

Since measurements can vary from one person to another and even one day to the next, we caution that your own measurements may vary.  Plus, manufacturers update carseats from time to time, so there is absolutely no guarantee that these measurements are accurate or will reflect your own product.  This information is provided simply for rough comparisons among models.  To compare up to four carseats within a category, simply use the “Compare Carseats” pull-down menu option at the top of this page, click the links on the sidebar or click the “Go to” jump menu on mobile devices or click one of the category links below:

Compare Carseat Features ExampleCompare Rear-Facing Carseats

Compare Convertible Carseats

Compare Combination Carseats

Compare All-In-One Carseats

Compare High-Back Boosters

Compare Backless Boosters

Compare Carseats (Main Page)

More information, along with individual Carseat Data Capsules can still be found at Car-Seat.Org.

Among other measurements, we have compiled highest and lowest harness slot heights, crotch buckle depths, seating width and depth, and product weight as well as child age, weight and height ranges.  Where possible, we have also included valuable features like seatbelt lockoffs and product information such as lifespan.

CarseatBlog is not responsible for inaccurate information, omissions or other errors.  Some products have incomplete data and we apologize for any missing information.  We will slowly confirm or replace submitted information with our own measurements, but for many products we rely upon contributors to supply these measurements.  We would like to give a big Thank You to MomToEliEm and everyone from who contributed to this project over the years.    It originally was going to be hosted at the now defunct website, but technical hurdles made it too difficult.  The best intentions to create a new website just to host the comparison tool also ran into some challenges, but now it has found a home at CarseatBlog and better late than never!  We hope you find it useful when shopping for carseats or giving advice to friends and family.

This is still a work in progress.  We will be adding new products, filling in missing data and making other improvements regularly, so please check back again when comparing carseats.  We do welcome suggestions for products, comparison categories and general feedback about the appearance and usability of our data.  Please keep in mind that it is a commercial software product so we are limited in how it looks and feels.  Feel free to leave us a comment by replying to this blog!

All information is Copyright© 2001-2015, Carseat Media LLC, All Rights Reserved

New Jersey Updated Child Restraint Law Goes into Effect September 1, 2015


NJ county mapOn September 1, 2015, New Jersey put into effect its new child restraint laws. These laws apply to everyone driving through the state, not just to motorists who live in NJ. Even if your vehicle is registered in Toronto, you are expected to comply with the vehicle & traffic laws of each state you are driving in. And that includes their child restraint laws.

We know that legal jargon can be very confusing and many parents who live in New Jersey (or who drive through the state) still have questions so here is a breakdown of the the new NJ carseat and booster seat law in plain English:

Children under the age of 8 (through age 7) are legally required to ride in the back seat* as follows:

  • Under age 2 (0-23 months) and weighing less than 30 pounds are required to use a rear-facing carseat with a 5-point harness. This means a convertible used in the rear-facing position or an infant seat. (Note: Most babies will outgrow an infant carrier before their 2nd birthday and will need to transition to a convertible seat used in the rear-facing position. Unless you start off with a convertible seat from birth and then there is no need to transition to a bigger rear-facing seat.)

Rear-facing only (infant) carseat convertible seat installed reat-facing

  •  Age 2 through age 3 (24-47 months) secured in a carseat with 5-point harness either rear-facing (until reaching the weight or height limit) or forward-facing. Having a 3-year-old in just a booster seat is not legal unless they weigh more than 40 lbs.

Diono-Rainier-Clara  Nautilus2

  • Age 4 through age 7 (48 months until 8th birthday) and less than 57 inches tall (4’9″) secured in a forward-facing carseat with 5-point harness or a booster seat. There is no weight requirement in this updated law – only age and height requirements. (Note: If you have an older child who weighs more than 80 lbs. and you’re having a hard time finding a booster seat that they actually still fit in – consider a Safety 1st Incognito Kid Positioner. It’s specifically designed for bigger, older kids.)

Evenflo SK Platinum - harness Jon Turtle Booster Evenflo Amp

  • Age 8 through 17 shall wear a properly adjusted and fastened seat belt

Passing the 5 Step Test

*Exemptions: If there are no rear seats (e.g., standard cab pickup truck), the child shall be secured in a carseat or booster in the front passenger seat except that no child shall be secured in a rear-facing carseat in the front seat of any motor vehicle which is equipped with a passenger-side airbag that is not disabled or turned off.

Full text of the new law can be found here:

NJ Updated Law

Convertible Carseat Ratings – June 2015 Consumer Reports Update

Britax Marathon ClickTight, Britax Boulevard ClickTight and Graco Contender 65 Score High Ratings for Convertible Carseats

CR rockIn June, Consumer Reports added new models to their convertible carseat ratings.  A few newly tested products did quite well, with the Britax Marathon ClickTight and Boulevard ClickTight topping the overall ratings.  The Graco Contender 65 also did quite well overall, just above its competitors in the budget “Best Buy” category of highly rated models.

With new weight limits on the LATCH system of attaching carseats, seatbelt installations are back, especially for heavier forward-facing children.  So, we love the ClickTight system for super easy seatbelt installs, and the Boulevard CT (Our Review) and Advocate CT also offer exceptional rear-facing height limits and appear in our Recommended Carseats list.   We also share concerns at Consumer Reports about a possible harness issue on certain ClickTight convertible models.  While new models are revised to address this concern, we still advise parents to check the harness system periodically to verify.

It’s important to point out that this round of ratings is based on crash test results using their previous testing methodology (30 mph, FMVSS 213 standard bench, testing with 3-point lap/shoulder seatbelt or LATCH and no blocker plate). Convertible seat testing with their new crash test methodology is underway, but those results will not be published until some time later this year. For more info on Consumer Reports’ new crash testing program please see our previous blog on the subject:

The Safest Infant Carseats? New Crash Protection Ratings and Methods from Consumer Reports

Currently CR evaluates carseats on several points, including fit-to-vehicle, ease-of-usage, price and crash test performance. We can’t comment on specific scores but after our meeting with CR last year, we do have a general idea of how their ratings are assigned within these categories.

They break down the convertible carseat ratings into 3 categories:

  • Convertible seats rated to 40 lbs.
  • Convertible seats rated to weights higher than 40 lbs. (what we call “higher-weight harness” convertibles)
  • All-in-One seats that can be used rear-facing, forward-facing and also as a belt-positioning booster.

In the updated over 40 lbs. category, the Britax Marathon and Boulevard ClickTight models top the ratings, followed very closely by another of our Recommended Carseats, the Chicco NextFit.  After that, the rest of the Britax convertible lineup – Britax Advocate G4, Britax Boulevard G4, Britax Pavilion G4, Britax Marathon G4 and Britax Roundabout G4 all perform well. The Graco Contender 65Britax Roundabout G4 and the Evenflo SureRide were rated as “Best Buys” because they offer good value for their price but they also received good scores in all categories.  The Safety 1st Advance SE 65 was also added to the ratings with a very good crash protection score, but a middle-of-the-pack overall rating.

So, what is the “BEST” or “SAFEST” convertible carseat?  We are asked this all the time as Child Passenger Safety Technicians and it’s worth repeating the answer.  The BEST carseat is the one that fits your vehicle (installs tightly), fits your child (is appropriate for their age/weight/height), and that you can use correctly on every single ride. And of course it needs to fit your wallet too. The best carseat is not necessarily the most expensive carseat you can (or can’t) afford. And it’s not necessarily the carseat that matches the rest of your nursery collection or the one that everyone raves about online.  While no one can say which is the “SAFEST” carseat for any particular child or vehicle, if you’ve selected the “BEST” one for your own situation and install and use it correctly, then it will provide very good protection for your precious cargo.

While we think our Recommended Carseats list is a great place to start when shopping for the BEST carseat.  The seats on our list aren’t going to work for everyone and every situation. Remember – what works best for *your* child in *your* vehicle might not be the best choice for your sister or your neighbor or your friend, and that’s important. For example, a loosely installed carseat or one where you can’t easily adjust the harness to be snug on your child is not safe. A convertible carseat that doesn’t fit rear-facing in your car is not going to be the best choice for your child either.

The Ultimate Rear-Facing Convertible Carseat Space Comparison – Size Matters!

You can find Consumer Reports’ newest ratings on convertible seats at their website, Unfortunately, you have to be a paid subscriber to see the full ratings report.