But what makes a car seat an “all-in-one”?
This type of car seat combines a harness and a headrest into one piece, so you don’t have to adjust the fit based on your child’s size. They often have longer harnesses, which are more secure than the more standard 6-8 inches of adjustment. And they tend to be lighter than some other types of seats because they have fewer components.
Read on to find the best all-in-one car seats for your child.
Our Editor’s Best All In One Car Seat Reviews
Graco SlimFit 3 in 1 Car Seat -Slim & Comfy Design Saves Space in Your Back Seat, Darcie, One Size

Key Features:
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This car seat is for a child that is 5-40 pounds and it is a rear-facing harness. The seat then grows with the child to a forward-facing harness for a child that is 22-65 pounds. The last stage is a highback booster for a child that is 40-100 pounds.
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This is a slim car seat with dual cup holders that rotate away, making it 10% slimmer to save back seat space.
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The Graco ProtectPlus Engineered car seat is a seat that has been designed to protect a child in a variety of different types of crashes. This includes frontal, side, rear and rollover crashes. The seat has undergone a number of rigorous crash tests to ensure that it is up to the task of protecting a child.
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This car seat has a harness system that can be adjusted without having to rethread it. The headrest and harness can be adjusted together in one motion.
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This car seat has 10 positions for the headrest, so that you can find the safest fit for your child as they grow.
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This all in one car seat has a 4-position recline that keeps your child comfy. It also helps for a better installation.
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This car seat has a push-button InRight LATCH system that allows for easy, one-second attachment with an audible click to help ensure secure installation.
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The all in one car seat has a harness storage compartment that keeps the harness safely stored while in belt-positioning booster mode. This is a great feature for a shopper who wants a car seat that can be used in both modes.
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This car seat has a steel-reinforced frame that provides strength and durability for 10 years of use.
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The all in one car seat has a level indicator that is easy to read. This helps to eliminate installation guesswork.
Maxi-Cosi Pria Max 3-In-1 Convertible Car Seat, Nomad Sand

Key Features:
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This all-in-one car seat is a 3-in-1 seating system that can be used as a rear-facing seat for a 4 to 40 pound child, a forward-facing seat for a child up to 65 pounds, or a booster seat for a child up to 100 pounds.
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This all in one car seat has side impact protection with GCell, which protects your child’s head in a side impact crash.
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The Clipquik auto magnetic chest clip is a car seat that is designed to be easy to use and get you on your way quickly. The chest clip is magnetic and attaches to your clothing, so you don’t have to worry about it coming loose or falling off. The seat is also comfortable and has a built-in headrest for added support.
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This is a car seat that has spring assisted harness covers that make it easy to get the child in and out of the seat.
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The buckle on this car seat flips away, so it won’t get in the way when you’re getting in and out of the seat.
Safety 1st Grow and Go All-in-One Convertible Car Seat, Rear-facing 5-40 pounds, Forward-facing 22-65 pounds, and Belt-positioning booster 40-100 pounds, Harvest Moon

Key Features:
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This car seat is suitable for a child weighing between 5 and 40 pounds when used in the rear-facing position, 22 and 65 pounds when used in the forward-facing position, and 40 to 100 pounds when used as a belt-positioning booster.
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The all in one car seat has side impact protection to help keep your child safe.
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The all in one car seat is easy to put on and take off, with harness holders that keep the harness in an open position. It is suitable for rear-facing use for children 19 to 40 inches tall, and can be used for forward-facing children 29 to 52 inches tall.
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The Quickfit harness is a car seat feature that allows the user to adjust both the harness and headrest in one step. This is a convenient feature for parents who want to be able to quickly and easily adjust their child’s car seat.
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This is an all-in-one car seat that has a machine-washable and dryer-safe seat pad. It also has snaps that make it simple to take off of the seat, making it easy to clean.
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This car seat is a universal all-in-one seat that can be used for infants, toddlers, and young children. It features a one-click installation system that makes it quick and easy to install. The seat also has adjustable straps and headrests to ensure a comfortable and secure fit.
Maxi-Cosi Pria All-in-One Convertible Car Seat, All-in-One Seating System: Rear-Facing, from 4-40 pounds; Forward-Facing to 65 pounds; and up to 100 pounds in Booster Mode, Sonar Grey

Key Features:
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The all-in-one convertible car seat can be used rear-facing for a weight range of 4-40 pounds, forward-facing for those weighing up to 65 pounds, and also in booster mode for those up to 100 pounds.
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This is a car seat that has side impact protection technology. It has GCell technology which protects your child’s head in a side impact crash.
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The all in one car seat has harness holders that keep straps out of the way when buckling. This is convenient for when you need to put the car seat in and take it out.
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The all in one car seat has a one click LATCH system that makes it easy to install.
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This all-in-one car seat is designed to make it easy to get a proper fit for your child. The QuickFit shoulder harness automatically raises the harness and headrest height as your child grows, so you don’t have to keep readjusting the straps. The seat also features a padded, adjustable headrest and a five-point harness for safety.
CYBEX Eternis S with SensorSafe, Convertible Car Seat for Birth Through 120 Pounds, Up to 10 Years of Use, Chest Clip Syncs with Phone for Safety Alerts, Toddler & Infant Car Seat, Lavastone Black

Key Features:
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This is an all-in-one car seat that can be used for up to 10 years. It has an in-seat recline to help provide correct ergonomic positioning, and extra legroom for rear-facing use.
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This is an all-in-one car seat that features SensorSafe technology. This technology automatically syncs to the phone app to provide alerts if unsafe situations arise, including your child becoming unbuckled, the back seat being too warm or cold, or if the child is seated too long.
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This is an all-in-one car seat that can be used in rear-facing, front-facing, and belt-positioning booster modes. It is designed for use from birth up to 120 lbs.
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This car seat has Linear Side Impact Protection, which means that it can absorb up to 25% more impact forces in certain crashes than a car seat without this protection. This can help to keep your child safe in the event of a crash.
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This car seat has a patented reclining headrest to help prevent the child’s head from falling forward while asleep. The headrest also has 12 height settings for easy adjustment as the child grows.
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This is an all-in-one car seat that can be converted into a booster seat as your child grows. It is suitable for children between 40 and 120 pounds. It has a comfortable high back and is belt-positioning.
Evenflo Gold Revolve360 Rotational All-in-1 Convertible Car Seat, Swivel Car Seat, Rotating Car Seat for All Ages, Swivel Baby Car Seat Mode Changing 4-120LB Car Seat and Booster Car Seat

Key Features:
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This car seat is designed to make it easy to get your child in and out of the car, no matter what type of vehicle you have. It features an innovative rotating design that makes it easy to access your child.
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The Revolve360 is an all-in-one car seat that is easy to install and secure. The Sure360 Safety Installation System with LockStrong and Tether360 keeps it safe and simple.
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The all in one car seat offers 10 years of use and 3 modes—Rear Facing (4 – 40 lb), Forward Facing (22 – 65 lb), and Booster (40 – 120 lb).
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This all-in-one car seat is designed for maximum comfort and convenience, with an easy-to-use recline feature that lets you adjust your child’s seat without having to reinstall the seat or disturb your baby.
Chicco Fit4 4-In-1 Convertible Car Seat – Onyx | Black/Grey

Key Features:
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This car seat is designed to be comfortable for your child at every stage of their growth, from birth to age ten. It is easy to install and secure, so you can have peace of mind knowing your child is safe.
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This all in one car seat is designed to provide a comfortable and custom fit for your child as they grow. It features a four-stage construction that can be easily removed and adjusted to accommodate your child’s changing size, and includes a built-in harness system to keep them safe and secure.
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The Chicco car seat is an all-in-one seat that is easy to install correctly. It has a ReclineSure leveling system, RideRight bubble levels, force-multiplying SuperCinch LATCH tightener, and LockSure belt-tightening system.
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This is a car seat that has a steel-reinforced frame and EPS energy-absorbing foam that surround the head and torso. It has a best-in-class 10-position headrest that accommodates maximum growth.
Evenflo All4One DLX 4-In-1 Convertible Car Seat (Kingsley Black)

Key Features:
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The car seat is for infants to toddlers to kids. It has a rear-facing harness and a forward-facing harness. The high-back booster helps keep the child in the seat. The no-back booster is for when the child is bigger.
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This car seat is designed to be installed quickly and securely. It has a LATCH system that can be tightened in seconds, and is three times tighter than similar systems from other manufacturers.
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The all in one car seat for a shopper is a car seat that has a sensor that sends messages to your phone if there is an unsafe condition in the car, such as the chest clip unbuckling, unsafe temperature in the car, child unattended in the car, or child seated too long.
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The all in one car seat is certified to meet low chemical emissions standards, creating a healthier environment for your child.
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This car seat includes a headrest and body pillow for comfort, as well as a Quick Clean Cover that can be easily removed and washed.
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This car seat is for a child that weighs between 4.0 and 120.0 lbs and is 17.0 to 57.0 inches tall.
Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Jet Black

Key Features:
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This car seat is designed to be used in a rear-facing position for longer, up to 50 lb or 22.7 kg, approximately 4 years old.
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The Radian 3R is an all-in-one car seat that can be used for infants, toddlers, and children up to 120 lb / 54 kg. It has four ways to be used, including a rear-facing seat for infants, a forward-facing seat for toddlers, a booster seat for children, and a backless booster for children. It is made to offer a custom fit for each child, and has a 10-year lifespan.
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The all in one car seat has a steel core that is reinforced and made from automotive grade high strength steel. This steel protects the seat and keeps it in good condition.
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This is a car seat that can accommodate three children at once. It is slim in design so that it does not take up a lot of space in the car. The car seat is also comfortable for the children.
Maxi-Cosi Pria Max All-in-One Convertible Car Seat, rear-facing, from 4-40 pounds; forward-facing to 65 pounds; and up to 100 pounds in booster mode, Nomad Black

Key Features:
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This is a 3-in-1 convertible car seat that can be used rear-facing for a 4-40 pound child, forward-facing for a child up to 65 pounds, and in Booster mode for a child up to 100 pounds.
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The all in one car seat for a shopper has side impact protection technology with GCell. This protects your child’s head where it’s needed most in a side impact crash.
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This car seat has a Clipquik auto-magnetic chest clip that makes it easy to get on and off.
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This all-in-one car seat is designed for easy boarding, with spring assisted harness covers that stay out of the way.
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This is a convertible car seat that has a flip away buckle. This feature prevents the buckle from getting in the way while getting in and out of the seat.
All In One Car Seat FAQs
1. What is an all in one car seat?
An all in one car seat is a seat that can be used as a rear-facing seat, a forward-facing seat, or a booster seat.
2. How does an all in one car seat work?
An all in one car seat typically has a five-point harness system and can be used in both rear- and forward-facing positions. The seat can also be converted into a booster seat for older children.
3. What are the benefits of an all in one car seat?
Some benefits of an all in one car seat are that they can be used for a longer period of time, they can be used for different weight ranges, and they can be used for different height ranges.
4. What are the drawbacks of an all in one car seat?
The main drawback of an all in one car seat is that it can be bulky and heavy, making it difficult to move from one car to another. Additionally, all in one car seats can be more expensive than other types of car seats.
5. How do I choose the right all in one car seat for my child?
The best way to choose the right all in one car seat for your child is to consult with a certified car seat safety technician. They will be able to help you choose the seat that is best for your child’s height, weight, and developmental needs.
Conclusion
There are many great all in one car seat on the market. Our list of the best all in one car seat will help you save time researching and choosing the best one for you.