What is an All-in-One Car Seat? - Baby Chick
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What is an All-in-One Car Seat?

Parents know what an infant car seat is and a converitble, but what is an all-in-one car seat? We're answering this question and much more.

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Updated April 23, 2024

by Nina Spears

The Baby Chick®: Pregnancy, Birth & Postpartum Expert

The majority of parents (especially first time parents) are familiar with infant car seats. Infant car seats are regularly recommended and referred to when discussing car seats for newborns. This is why many families choose them as their first car seat purchase for their baby. However, a lot of parents are unaware that there are convertible car seats and all-in-one car seats that can also safely accommodate their new little ones and grow with them for years to come. And if parents are aware of these choices, many don’t know all of their benefits and why they may want to consider one as their first car seat for their child.

I’ve previously talked about convertible car seats and their benefits so now I am diving into all-in-one car seats. What makes them different? Why should parents consider them when shopping for their baby? And what should you look for when considering one for your child? I’m covering it all!

Buckling in a toddler girl into the NUNA EXEC all-in-one car seat.

What is an all-in-one car seat?

An all-in-one car seat is a child safety seat that can be used for children starting anywhere from as little as 5 pounds to as high as 120 pounds and 57 inches tall. All-in-one car seats can also be referred to as 3-in-1 car seats or 4-in-1 car seats:

To keep it simple, a 3-in-1 car seat goes from infant seat to booster seat: rear-facing, forward-facing, and high-back booster.

And a 4-in-1 car seat goes also goes from infant seat to booster, but includes one more step: rear-facing, forward-facing, high-back, and backless booster.

So when you are looking for an all-in-one car seat, understand that the car seat will go from rear-facing to forward-facing and booster. While researching all-in-one car seat options, you could be looking at 3-in-1 car seats and 4-in-1 car seats. Essentially they are safety seats that will grow with your child and could be the last car seat you’ll ever need. This is why all-in-ones are labeled as the ones that “do it all.”

Nina Spears showing how the NUNA EXEC all-in-one car seat can recline and the head rest can raise.

What is the difference between a convertible car seat and an all-in-one car seat?

You may be wondering what is the difference between a convertible car seat and an all-in-one car seat. They look similar, but they are indeed different. A convertible car seat is a child safety seat that can rear-face and forward-face, and an all-in-one car seat goes another step beyond and can be used as a booster. So if you choose a convertible seat, you will eventually also need to invest in a booster seat for your child. With an all-in-one, you don’t have to. It has it all-in-one. 🙂

Something else that differentiates this all-in-one car seat from a convertible is the anti-rebound panel/multi-functional leg rest. I particularly love that it is multi-functional: it’s a anti-rebound panel for extra safety and security in the rear-facing position and when your child grows and is able to face forward in their seat, it is an adjustable leg rest. Such a great feature!

The NUNA Exec all-in-one car seat

A Closer Look at an All-In-One

There are many benefits to buying an all-in-one car seat for your baby. One of the biggest benefits is that it truly does grow with your child. Here’s a look at the new EXEC all-in-one car seat from NUNA as an example and how it transitions from supporting an infant, toddler, little kid to big kid.

For an Infant

The NUNA Exec with a newborn baby doll.

An all-in-one car seat can be used as your baby’s first car seat from day one. For example, the EXEC can seat babies as little as 5 pounds and stay rear-facing up to 50 pounds and 49 inches tall. It includes all of the infant inserts to safely and comfortably seat your newborn. I love that the inserts can easily be removed and that you can tuck in the tabs when your child out grows the inserts.

Unsnapping the infant inserts in the nuna car seat.
Tucking in the infant insert snaps inside the Exec Nuna all-in-one car seat.

For a Toddler

This sweet little toddler is 18 months old, 35 inches tall and 27 pounds. She is obviously too big for an infant car seat, but is still within the recommendation of sitting rear-facing. This EXEC all-in-one easily converts to a convertible seat for this toddler girl. 🙂 Just adjust the recline position to your preference or your child’s preference and select a height for the correct head support.

Toddler sitting in the NUNA all-in-one car seat called the EXEC.

For a Little Kid

Once your child has exceeded the car seat’s weight and height limits for rear-facing, it’s time to turn the car seat to forward-facing! That’s what’s great about all-in-one car seats. You are familiar with the seat and so is your child. Now they can have a whole new view! Here is a young boy who is 4.5 years-old, is 48 inches tall and weighs 40 pounds. He is perfectly within the safe range of forward-facing with the harness.

Little boy sitting in the NUNA EXEC all-in-one car seat forward-facing.

For a Big Kid

And when your child is no longer so little, they will graduate to the booster seat. Say bye-bye to the harness and hello to the seat belt. Your big kid will sit forward-facing in their all-in-one car seat without the harness and instead use the safety belt. This is the booster mode. (Check your car seat’s manual for proper installation.) This big girl is almost 6 years old, is 51 inches tall and weighs 41 pounds. The booster is perfect for her current size and with the NUNA EXEC she’ll be able to ride in the booster mode until she reaches either 120 pounds or 57 inches tall.

Young girl sitting in the NUNA Exec all-in-one car seat as a booster.


What are some other benefits to choosing an all-in-one car seat for your child?


If you choose an all-in-one car seat you will not have to research multiple car seats or go shopping for another car seat again. I know many parents who have rushed to find a new car seat because their child was about to outgrow their current one. Safety is important so don’t rush the decision-making and make a great decision the first time with something that will last. You will be grateful for the extra time not researching and your pocket book will thankful for the extra dollars saved down the road.

A woman secures a smiling child into a car seat inside a vehicle. The text on the image reads, "exec class security" and "Shop now" with a "Nuna" logo at the bottom.

Good for the Environment

All of the eco-conscious parents will appreciate this. (The minimalists parents will too!) We are creating so much waste by purchasing several car seats throughout our children’s’ lives. If you think about the process of manufacturing the car seat, the materials that go into making the car seat, the space to hold all of the inventory, the shipping, etc . . . it’s a lot. It really takes a toll on our environment. If you decide to buy a good quality all-in-one car seat that will last for years, you will have played a piece into creating less waste filling up our landfills. That’s pretty awesome.


I am a creature of habit and I try to avoid change when possible. This is another great reason, particularly for me to have an all-in-one car seat. Not only is this just convenient, but once you know how to properly and safely use a good all-in-one car seat, you won’t have to learn how to use another one. You’ll be familiar with its safety features and you won’t have to learn the differences of each new car seat. And not only that, your child will be more familiar with their car seat. This can also help them feel more comfortable as they transition their way from infant all the way to booster.

Buckling in a toddler girl into the NUNA EXEC all-in-one car seat.

Perfect for Partners and Other Caregivers

All-in-one car seats are also perfect for second vehicles (you’re partner’s car) or grandparents. No matter which kid they need to pick up and take to school or to an activity, an all-in-one can safely accommodate any of the kids.

Questions to Ask and What to Look for Before You Buy

What are the height and weight restrictions for rear-facing and forward-facing?

This is a big one. You want to know exactly how long your child will be able to use this all-in-one car seat. These numbers will tell you how long you can reasonably expect your child to use that seat. And if you have a tall child and your kid is always in the 90th or 100th percentile, you need a car seat that can keep up with your kid. Know the limit numbers!

How big is the car seat?

Is it super bulky? Some all-in-one car seats can be. Look for the measurements and see if it will allow two or three other car seats to sit across in the backseat. That’s another reason why I love the EXEC all-in-one. It can fit three across!

What materials is it made of?

Check to see what the all-in-one car seat you are looking into is made of. Maybe an all-steel frame is a must-have for you. Maybe organic fabrics or free of fire retardant chemicals is also essential. Do your research and determine if these things are important to you and your family.

The morino wool inserts and the organic cotton inserts for the Nuna Exec car seat.
How easy is it to install?

Some car seats can be really difficult and confusing to install. The last thing we want is for the car seat to be improperly installed. Read some reviews, watch some installation videos, and check some out in the stores and see how easy it is to install.

How many features and what features does it have?

Are you big into having all of the bells and whistles? See what features are included in the all-in-one car seat you are considering. With the EXEC, I particularly like the Simply™ secure installation (so easy), the no-rethread five-point harness and 12-position head support, the magnet harness keepers, dual cupholders, and the anti-rebound panel and leg rest. Just to name a few. 😉

Magnet harness keepers for the buckle on the Nuna Exec.
How do I clean it?

If you plan on this all-in-one car seat being “the one” then you need to know how easy it is to clean. Are the pieces machine washable? We know that kids can spill and make lots of messes and even get carsick. Ask these questions because you don’t want your car seat to be gross after a short period of time.

An all-in-one car seat might not be the right choice for every family, but I do believe that they would benefit many. My hope is that with this information more parents and other caregivers will look at all of their choices when choosing a car seat and truly get the best one for their family’s growing needs.

A young child sits in a Nuna car seat, facing forward with a smile. The text overlay reads, "exec™ class comfort" and "Shop now." The Nuna logo is displayed at the bottom of the image.
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Nina Spears The Baby Chick®: Pregnancy, Birth & Postpartum Expert
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Nina is The Baby Chick® & Editor-in-Chief of Baby Chick®. She received her baby planning certification in early 2011 and began attending births that same year. Since then, Nina has… Read more

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