How to Determine Which Car Seat to Use

The most common question when it comes to car seats is: which car seat to use?  The answer depends on where you live and your child’s age, height, and weight.

Your child’s age really only matters if its referenced in your state’s car seat laws. Infants under 1 year old are generally required to ride in a rear facing infant car seat. Some states, and most safety experts, recommend keeping babies in a rear facing car seat until they are 2 years of age. Also frequently referenced in state car seat laws are age 4 and age 8. Click here to find out more specifics about car seat rules in your state.

Three Types of Car Seats

  • Rear Facing
  • Forward Facing
  • Booster Seat

Other car seat styles you’ll see are convertible, combination, and 3-in-1 or All-in-1. A convertible or combination car seat is one that can be used for 2 of the 3 stages – either rear facing and forward facing, or forward facing and booster seat. An all-in-one car seat or 3-in-1 car seat is made to be used all three ways. 

No matter which type of seat you’re using, it’s very important that you read (and keep) the instructions that come with it. Know the weight and height limits for the seat, and it’s expiration date. Most state car seat laws include language that requires a car seat be installed and used according to the manufacturer’s recommendations. 

Rear Facing Infant Seats

Rear facing car seats are made for infants. This Graco SnugRide is a good example. It has a weight range between 4 and 35 pounds, and a height/length maximum of 32 inches.

Like most infant seats, this one has a separate “base” that is fastened in the vehicle using either the LATCH system or a seat belt. The “infant carrier” part has a 5 point harness in it which secures the child, and the carrier is clicked into the base.

Convertible Car Seats

Evenflo Tribute LX
Evenflo Tribute LX

Convertible car seats are those made to be used rear facing at first, then flipped to face forward. A 5 point harness is used in both cases. There will be different weight and height requirements for each type of use.

For example, this Evenflo Tribute LX has a rear facing safety rating of 5-30 pounds and 19-37 inches. Forward facing, it can be used for toddlers 22-40 pounds and 28-40 inches tall.

Combination Car Seats

Britax Frontier ClickTight
Britax Frontier ClickTight

Combination car seats can be used as a forward facing car seat with a 5-point harness, and later used as a booster seat. This type of child safety seat usually comes with a LATCH attachment option (not all booster seats do). When your child reaches the maximum weight limit for the 5 point harness, simply remove it.  The instructions that came with the seat will explain how to use it properly with a seat belt.

This Britax Frontier Clicktight model is a good example of a combination child safety seat. It can be used forward facing with the 5 point harness for kids between 25 and 90 pounds. Then it can be used as a booster seat for kids 40 to 120 pounds. The headrest and harness are adjustable to accommodate growing kids.

Booster Seats

The purpose of a booster seat is to make a seat belt (which are designed for adults) fit properly over a child. They are sometimes called “belt positioning booster seats”. Most booster seats lift a child up to accomplish this. They often also use an arm rest, clip, or headrest to guide the shoulder belt into proper position.

NOTE: Always use a booster seat with both the lap belt AND the shoulder belt. If your vehicle does not have shoulder belts in the back seat, please consult your state car seat law for safe alternatives.

There are primarily two types of booster seats: high back and backless. If your child’s ears (and back of skull) are taller than the vehicle seat, or if he or she falls asleep or can’t sit up straight for the whole ride, he or she needs a high back booster seat.

Evenflo Big Kid AMP Booster
Evenflo Big Kid AMP Booster

High back booster seats like this Evenflo Big Kid AMP Booster provide more support overall for kids who tend to sleep in the car or who don’t sit up consistently. They also offer a head rest. This minimizes risk of whiplash and provides more head and neck protection.

If a child can sit upright and his or her ears are below the vehicle seat back, he or she may ride in a backless booster seat. 

Many states allow kids who are AT LEAST 4 years old and AT LEAST 40 pounds to ride in a booster seat. However, safety experts recommend keeping your child in his or her forward facing car seat until they reach the maximum weight or height limit.

Graco Backless Turbo Booster
Graco Backless Turbo Booster

This Graco Backless TurboBooster has very common features of a backless booster. It needs to be secured with a seat belt, even when it’s not being used. This seat uses the arm rest to position the shoulder belt. It can be used for kids up to 100 pounds and 57 inches tall. At that height, an adult seat belt often fits correctly without a booster. See the links below for how to determine this.

Backless boosters don’t provide the head and neck protection that a high back booster does. They are not always adjustable, either. But they are very easy to install, and older kids tend to prefer them.

All-In-One Car Seats

Graco 4Ever
Graco 4Ever

All-in-1 car seats like this Graco 4ever model are by far the most expensive. But really, you’re purchasing 3 car seats in 1. These seats can be used as a rear-facing infant seat, a forward facing toddler seat, and a high back booster seat. 

As with convertible safety seats and combination safety seats, the approved weight and height ranges will vary depending on how the seat is being used.

All-in-1 car seats tend to have a longer life span. Average expiration of most car seats is about 6 years after manufacturing. All-in-1 car seats are usually good for 10 years. Of course, you’ll want to verify the expiration date for your specific seat. 

For more details on which car seat to use, including installation videos, check out This page also includes a downloadable 67 page PDF booklet with great safety tips, as well as info on installation, ease of use ratings, and finding the best car seat for your vehicle.

Which Car Seat to Use?