4 Car Seat Stages You Need to Know

What Are the Stages of Car Seat?

Based on the NHTSA’s suggestion and actually the children’s car seat laws in child passenger safety, there are four car seat stages that will take a child through their entire time from birth until they can begin to ride in the front seat after their 13th birthday.

The four stages of the car seat include rear-facing, forward-facing, booster, and seat belt.

Each stage will last for several years. Progressing from any of these four stages should not be rushed.

When it comes to child passenger safety, the best practice is to put off those milestones by using your safety seats to their maximum.

It’s the safest way to ride your child by keeping them in the current stage for as long as possible until they outgrow the height or weight limits allowed by the car seat manufacturers.

We’ll cover the basics of those four stages here. Sometimes, parents want a direct way to know the relationship between the car seat stages and ages and types, and weight and height. If you’re planning to explore these topics, you’re in the right place.

No more words, let’s start.

Car Seat Stages, Ages, Types, Weight and Height Limits

You’ll have an overall view of the car seat stages and ages and types and weight and height limits from the car seat chart. In the following parts, we’ll explain each stage and how to choose the right car seat to perfectly fit your child’s growth.

Car Seat Chat - Age, Stage, and Type
Car Seat Stage and Age

Car Seat Stage 1 - Rear-facing Car Seats until 2 Years Old

Rear-facing seats are designed for newborns, infants, and small toddlers. You need to use this type of car seat from birth until the littles exceed the top height or weight limit of their car safety seats.

Three types of rear-facing seats are available: rear-facing–only infant, convertible, and all-in-one (including 3-in-1 and 4-in-1).

You can move your little one to a convertible or all-in-one car seat when they’re approaching the height or weight limit, or just choose one since their birth.

Type 1: Rear-facing Only Infant Car Seats


Birth to 6-9 months


Minimum 4 to maximum 30 or 35 pounds


Maximum 32 inches tall


Last for one stage only

This type of seat is used for newborns and infants. Your baby will stay in this seat when he or she weighs between 4 to 35 pounds, depending on the model.

They are often coming with a lightweight and portable design with a separate base, which can be left in the car.

It’s really great so that you don’t need to remove and connect the base each time you use it. If you want to use the infant car seats in multiple vehicles but don’t want to buy several car seats, the separated base is available for sale. 

Some brands, especially well-known brands like Graco, provide you with a few options of buying more than one base if you’re looking for infant car seats with additional bases.

On the other hand, the infant car seat can be used as a part of a travel stroller system with a carrying handle.

It is a pity that the infant car seat can be only used for travel, not that good for sleeping, feeding, or other uses outside the vehicles.

Doona Infant Car Seat and Stroller

Doona Infant and Strolloer Combo

Type 2: Convertible Car Seats Used Rear-facing


Birth to 2-3 years old


Minimum 4~5 to maximum 40~50 pounds


Maximum 40~49 inches tall


Going through two stages

As your child outgrows beyond the maximum weight or height of a rear-facing infant car seat, you should change to a convertible car seat, as it supports a higher rear-facing weight limit up to 40-50 pounds.

Later, as your child grows to reach either the weight limit or the length limit, you can convert it to forward-facing. That means a longer lifespan to keep your child in the same car seat and save money.

Many parents prefer a convertible car seat because they only need to make one purchase for both rear-facing and forward-facing use.

However, convertible car seats are always bulkier than infant seats, and they don’t come with carrying handles or separate bases.

Generally, the convertible car seats provide 5-point harness systems to connect in five places: the shoulders, the hips, and the legs.

Type 3: All-in-one (3-in-1/4-in-1) Car Seats used Rear-facing


Birth to 2-3 years old


Minimum 4~5 to maximum 40~50 pounds


Maximum 40~49 inches tall


Going through three stages

The all-in-one car seats last longest of the three types and can be used rear-facing, forward-facing, and as a belt-positioning booster (including high back and backless). That means this type of car seat may be used longer by your child alongside their growth.

However, they can be much bulkier than other models, so it’s important to check if they fit well or not in your vehicle in the rear-facing mode, especially if you have a small car.

Just like the convertible car seat, they can handle higher weight loads about 40-50 pounds in the rear-facing position.

Best practices for a proper rear-facing fit in 1st Stage

The first and most important thing for a correct and secure installation is to read the vehicle owner’s manual and the car seat manual. And here are some tips and suggestions from official guidelines and other experienced parents.

  • Place the harnesses into the slots below or are your kid’s shoulders and the harness chest clip is placed at the center of the chest, even with your child’s armpits.
  • The car seat should be installed tightly in the vehicle, with no more than 1-inch movement from back and forth, left to right. When properly installed with either LATCH or a locked seat belt, this shouldn’t be a problem.
  • Remember to place the car safety seat in the back seat. Never in the front seat of a vehicle that has an active front passenger airbag.
  • Make sure the seat is at the correct angle so your child’s head does not move back and forth. You might need to adjust the angle to find the best angle with the built-in angle indicators or adjusters.
  • Make sure that there is enough space between the car seat and front seat after installing in the rear-facing position.
  • The seat belt or lower anchor webbing should be routed through the correct belt path if you are using a convertible or all-in-one seat in the rear-facing position

If you are still having questions, seek the help of a certified child passenger safety technician (CPST) in your area.

FAQs about Riding in Rear-facing in the First Stage

All infants and toddlers should ride in a rear-facing seat as long as possible until they reach the highest weight or height allowed by their car safety seat manufacturer. Most convertible and all-in-one seats have limits that will allow children to ride rear facing for 2 years or more.

Most parents are concerned that the baby touching the seat will cause leg injury in this situation. However, children can always find a comfortable way by bending their legs in the rear-facing seat. So it’s fine for this case and you don’t worry too much about it.

Your child is too young to keep himself or herself sitting straight in a rear-facing car seat. So you can try to supplement the car seat’s construction with blankets to either side, a diaper on the crotch strap, or a bigger infant car seat around the head. Do not put anything behind your kid.

It’s better to dress your kid in thinner clothing in the car seat to make sure the car safety seat will function properly and reduce the risk of injury, as bulky clothing like winter coats or snowsuits could compress in a crash and leave straps too loose to restrain your kid. You can dress your baby in thinner layers and wrap a coat or blanket around your baby over the buckled harness straps if needed. See Winter Car Seat Safety Tips from the AAP.

Not all car seats fit well for very small newborns. Generally, the rear-facing-only infant car seats usually fit better for very small babies in a semi-reclined position. So make sure you have asked the hospital that will typically tell you whether or not your seat is a good match for your baby and the best angle.

Better NOT. It’s not that safe. Infants in rear-facing car safety seats should not be placed in front passenger seats when an airbag is present and activated. If no appropriate rear seating position is available, only place the infant in the front passenger seat if an airbag on/off switch is installed and turned off.

Stage 2 - Forward-facing Car Seats Until 7 Years Old

After your kid outgrows the weight limit or the height limit of a convertible or 3-in-1 car seat in the rear-facing position, you need to turn the car seat to forward-facing mode. This kind of car seat has a harness and tether that limits your child’s forward movement during a crash to ensure his or her safety.

As introduced above, both convertible and 3-in-1 car seats support both rear-facing and forward-facing positions; you can just turn them around from rear-facing to forward-facing. But you still always keep this note in your mind: make sure you have read the vehicle owner’s manual and the car seat manual before installing the seat.

Convertible Car Seats used Forward-facing


2-3 years old to 6-7 years old


minimum 20~25 to maximum 65~85 pounds


maximum 49-52 inches tall


Going through two stages

All convertible car seats can be used for both rear-facing and forward-facing positions. Most convertible car seats have a weight limit of 65 pounds, some can even have a higher weight limit up to 85 pounds, like the Maxi-Cosi Praia 85 Max. This type of car seat always has a 5-point harness or 3-point harness system for better safety.

All-in-one Car Seats (3-in-1 or 4-in-1) used Forward-facing


2-3 years old to 6-7 years old


minimum 20~25 to maximum 65 pounds


maximum 49-54 inches tall


Going through three stages

These car seats have the longest lifespan, holding your baby from birth to the seat belt age. Used in the rear-facing position, they have a weight range from 4 pounds to 40 pounds; Installed in the forward-facing mode, they can hold kids from 20 pounds to 65 pounds; Later when your child is ready to stay in a booster car seat, they allow up to 120 pounds limit till your child can use a seat belt.

Forward-facing only Harness Booster


2-3 years old to 8-10 years old


maximum 57-63 inches tall


Maximum 40~49 inches tall


Going through two stages

Harness booster seats can be used forward-facing only. But it will last for two stages of use – forward-facing harness and booster. When harnessing mode, they work similarly to the convertible car seats with the 5-point harness

Forward-facing Car Seats Installation Tips

Always remember to read the vehicle owner’s manual and the car seat manual before installing the seat. Make sure that the car seat is installed tightly in the vehicle to provide your kids with the highest safety and greatest comfort as promised.

When switching the convertible car seat or 3-in-1 car seat from rear-facing to forward-facing, here are some installation tips:

Move the shoulder straps to the upper slots that are at or above your child’s shoulders in the correct position.

Make sure the car seat will sit more upright in the vehicle by adjusting the recline angle of the seat. If you don’t know how to achieve this, check the instructions to be sure, or call the car seat manufacturer.

If using the lower anchors, the weight of your child plus the weight of the seat can’t exceed 65 pounds. If the child grows and weighs too much, you must use the seat belt to install it.

When you are using a seat belt as a buckle, make sure it runs through the forward-facing belt path, which is a bit different from the rear-facing belt path. Check and follow the car safety seat instructions. Always check that the seat belt is locked and tightened enough or not.

If possible, always use the top tether to lock the seat as much as you can. Find the tether straps for forward-facing usage with the tether anchors that are required to have in all new cars, minivans, and light trucks as of September 2000.

Follow the car safety seat instructions to find the top weight limit and check the vehicle owner’s manual for locations of tether anchors.

Forward-facing Car Seats Frequently Asked Questions

Don’t rush too soon to turn the rear-facing to forward-facing, as long as your kid doesn’t reach the rear-facing car seat weight limit or the height limit. It’s recommended to keep your child in the rear-facing car under 2 years old, then switch to the forward-facing position when he or she reaches the maximum weight limit or height limit of a rear-facing car seat, no matter if it’s a convertible or 3-in-1 car seat.

Yes, there are studies showing that the center of the back seat is the safest place to install the forward-facing car seat for toddlers under 3 years old. But most parents prefer to have the car seat installed behind the passenger seat in the back seat, for ease of taking the kids in and out.

NOT recommended. If there is a case that you have to put a forward-facing seat in the front there is an airbag present, you must be sure that the car seat is as far back as possible and the child seat is tightly and securely held to maximize the distance between the child and the airbag.

It’s best to avoid this situation. Many states have laws indicating that all children younger than 13 years should ride in the back seat. If absolutely necessary, a child in a forward-facing seat with a harness may be the best choice to ride in front, but to make sure the vehicle seat is moved as far back away from the dashboard (and airbag) as possible.

Tips: If you have two kids to ride in the car, you can put the most vulnerable, the ie. youngest child, in the center.

Before you let others drive away with your child, check with the following tips to make sure he or she is driven safely: a) You child is sitting in a car seat; b) the car safety seat is appropriate for the size and age of your child; c) the seat is properly installed in the vehicle for transportation, and d) your child is transported by someone has a valid driver’s license and knows how to install and use the car safety seat correctly.

If your child is transported by child care or schools, additional tips for your to check: e) there should be a supervisor, either school staff or a parent volunteer, to take care of the children so that the driver can focus on driving; f) school staff, teachers, and drivers should know what to do in an emergency, know how to properly use car safety seats and seat belts, and be aware of other safety requirements.

From the Federal Aviation Administration (FAA) and the AAP advice, it’s recommended to securely fasten the children less than 40 pounds in certified child restraints when flying. A car seat can help keep them safe during takeoff and landing or in case of turbulence. However, not every car seat can be used on an airplane, most rear-facing, convertible, and forward-facing seats are great to be used on airplanes, but booster seats and travel vests are not.

Stage 3 - Booster Car Seats for 12-13 Years Old or Younger

After the children outgrow their forward-facing car seats, they need to stay in booster car seats. Typically, if your child ages from 8 to 12 years old and reaches 4 feet 9 inches in height, it’s time for you to consider a booster seat. But most children between the ages of 8 and 12 have their own minds not wanting to stay in a booster seat. At this time, you should insist on using a car seat for their safety’s sake because they haven’t reached the weight or height to use the car seat belts like an adult. Before the age of 13, your child should be right in the back seat row.

You can find find the weight and height limits for the forward-facing car seat by checking the car seat manuals or instructions, but here are some general guidelines for you to check if a booster car seat is needed or not:

  • He/she reaches the maximum weight allowed for his seat with a harness.
  • He/she reaches the top height allowed
  • His/her shoulders have reached the top harness slots
  • The tops of his ears are above the top of the seat

Types of Booster Car Seats

The booster car seats are available in two basic types: high-back and backless. They don’t have the harness straps but use the lap and shoulder seat belts in your vehicle for fastening. It’s the same as an adult riding in a car. The purpose of a booster car seat is to raise your child up to ensure that the lap and shoulder seat belts can fit properly over the strongest parts of the child’s body for the best safety. The 3-in-1 car seat belongs to the high-back booster seats.

Booster Seats: High-back vs Backless

Both types of booster seats provide the best protection for your child, but there are a few differences between high-back booster seats and backless boosters and both have their own advantages and disadvantages.

High-back Booster Seats


1. High-back boosters provide head support while backless boosters don’t have a back for this type of support. The head support is extremely important for your child if your vehicle doesn’t have headrests in the rear seat, or if the headrests are not tall enough to protect your child’s head when the booster is in place. 2. High-back boosters also provide head protection from the side. The side bolsters in a booster seat helps to keep your child’s head during an impact, and often contain foam that will absorb energy in a crash. Furthermore, they also give the children a spot to rest their heads for sleeping.


High-back boosters are the safest choices, but they also have two disadvantages: price and weight. 1. The high-back booster seats generally cost more, coming with prices ranging from under $100 to over $300, than backless boosters that are usually sold at an affordable price under $100. 2. They are also heavier, making them not as easy to use as backless boosters if you frequently transfer the seat between vehicles.

Backless Boosters


1. One of the biggest pros of a backless booster seat is a better fit for children that are heavier or taller for their age. 2. The backless boosters will provide a few more inches in the headspace.


1. Backless boosters have a higher weight minimum than high back models. That means there might be a gap between the forward-facing car seats and the backless boosters. 2. They must be used with a high vehicle seat or vehicle headrest to ensure your child’s safety.

Installation Tips for Booster Seats

Like installing other car seats, you always need to read the vehicle owner’s manual and the car seat manual before installing the booster car seats. Booster seats usually come with a plastic clip or guide that will help you correctly position vehicle lap and shoulder belts. If you don’t know how to use it, check and follow the booster seat instructions.

Booster car seats must be used with a lap and shoulder belt. When using a booster seat in your vehicle, make sure:

The lap belt is low and snug across your child’s upper thighs.

The shoulder belt crosses the middle of your child’s chest and shoulder and should be below the neck.

If your booster seat has lower anchors or top-tether attachments, check its booklet for installation instructions.

Booster Car Seats Frequently Asked Questions

It’s fine to use the lap belts for rear-facing only, convertible, and forward-facing car seats, but straps are required to work with a booster car seat. If your car does not have shoulder straps across the back, consider using a forward-facing seat that has a harness and higher weight limits, like the 3-in-1 or all-in-one seats. You could also check to see if you can have them installed in your car, use a travel vest, or consider buying another car with both lap and shoulder belts in the back seat.

All boosters have a minimum weight and age requirement for children to use them. Make sure you have checked its minimum weight before buying a booster seat. Be aware that even though many boosters have a minimum weight as low as 22 pounds that most 3-year-old kids can reach this minimum standard, it’s not recommended to use a booster for the small kids aged under 4 years. You can check this post about car seat stage and age.

It’s recommended to use a booster seat for older children when they are at least 4’9″ and between 8 and 12 years old. And you should keep your child in a booster car seat until he or she is ready for the vehicle safety belts, which are designed for 165-pound male adults.

Based on the AAP’s recommendations, kids aged between 8 and 12 years should be kept in booster seats, until they are ready for adult seat belts when they reach 4’9”. However, most children will not reach this minimum height requirement to fit well in most vehicle seat belts without a booster until 10 to 11 years of age. Always remember, the back seat is the safest spot for your child.

Each state has laws on car safety seats.

How To Identify The Right Stage?

Your little one will progress through several car seat stages from the time he is born until adolescence. To ensure you’re using the safest option, double-check that your child meets the minimum height and weight requirement for a seat and is approaching the maximum measurement for his current car seat. 

“For all types of seats, weight and height limits will vary by model and manufacturer — always follow the guidance provided on the car seat labels and in the instructions for the seat your child will be using,” says Sarah Haverstick, a safety advocate and certified child passenger safety technician for Evenflo. “Every car seat fits in every vehicle differently, so it is a good idea to ask the store if you can test for fit with your vehicle and child before you make a purchase.”

Knowing which car seat to use at each stage of your child’s development can be confusing. The most important thing to remember is to not rush your child from one car-seat stage to the next. Children should remain in their current car seat stage, whether it’s a rear-facing, forward-facing, or booster seat until they reach their weight or height limit. This information can be found in the car seat manual or on the car seat itself.

FAQs of Car Seat Stage

Typically, stage 2 starts from two years old, meaning your child is ready to face forward in a 5-point harness car seat.

Stage 2 car seat generally means the 5-point harnessed car seat installed facing front. It includes convertible, combination, all-in-one. These three types have similar weight limits and ranges in the 5-point harness mode, typically between 22-65 pounds. Some have a lower of 20 pounds minimum weight requirement, like Britax’s convertibles – Adocate, Boulevard, and Marathon. Some may have a higher of 25 pounds, like the Chicco MyFit Harness Booster.

No. Your child should be at least 4 years old to ride in a booster seat.  Or he or she reaches the 40-lb minimum weight requirement.