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When to Change your Child's Car Seat

Medically Reviewed by Kristen Gardiner, CPST
Keep your little ones safe by ensuring they have the right seat.

Have you noticed your child’s head protruding above their car seat? It’s happening, mama. It’s probably time to start looking for a new car seat.

Your child’s inevitable growth isn’t the only reason for an upgrade. You’ll also need to shop for a new seat if yours expires or is in your vehicle during an accident.

As a passenger safety technician, I’m always happy to share what I know and will answer all your burning questions about switching car seats.

Keep reading to learn how to keep your little ones safe and secure in the correct car seat.

Key Takeaways

  • Outgrow car seat restrictions: Check height and weight limits and local laws to ensure your child is in the appropriate car seat for their age and size.
  • Different car seat types: Infant seats, convertible seats, forward-facing seats, and booster seats each have unique weight and height restrictions.
  • Car seat expiration and accidents: Replace car seats that have passed their expiration date or have been in a moderate or severe accident for safety reasons.
  • Proper disposal: When upgrading, recycle or dispose of old car seats correctly by following recycling center guidelines or participating in trade-in events.

Outgrowing Restrictions

Chances are high that you’re here because your child never seems to stop growing. This is not a bad thing. But it can come as quite a surprise when you find they no longer fit in their car seat.

A properly fitting car seat will be more comfortable for your child and keep them safer. There are also laws in place that require children to be in age-specific seating.

For example, in Ohio, children under 4 years are required to be seated in a child restraint system, or five-point harness.

Between the ages of 4 and 8, your child is legally allowed to use a booster seat (although most children aren’t mature enough to sit still in a booster until age 5, and many need to use the booster past age 8).

From ages 8 to 15, children are required to be in a child restraint or seat belt depending on their height and weight (1).

It’s important to remember that state laws are usually the bare minimum standard for car seat safety. Many laws are outdated. The best practice is to max out the height and weight limits of your car seat before moving to the next stage.
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Editor's Note:

Kristen Gardiner, CPST

So when do you switch your child due to height or weight limits? It varies depending on the car seat.

Many manufacturers are designing their seats to last longer, with some being convertible seats or all-in-one seats (infant seat to booster). Keep your child’s age, height, and weight in mind when choosing the correct seat.

Infant Seat Restrictions

Most infant seats will accommodate your child up to 22 to 35 pounds or more (2). This may seem like you can use the seat for longer (my 3-year-old has just now hit the 34-pound mark), but be aware that height comes into play too.

There isn’t one set height limit for a seat because it depends on the height of the infant seat back. A good sign you need to switch is if there’s no longer an inch of space between the top of your child’s head and the top of their seat. Check your manual for further information on height limits.

Safe Kids Worldwide recommends that children should ride rear-facing until at least age two (3). This means if your child outgrows the infant car seat before age two, you’ll likely need to purchase a convertible seat next.

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Convertible Seat Restrictions

The height and weight restrictions on convertible car seats vary greatly. While many convertible car seats will accommodate up to 65 pounds, some will go even further as they’re considered “all-in-one” seats (4).

Some all-in-one seats can be used up until your child reaches 120+ pounds.

Convertible seats are meant to last much longer than infant seats, so you’ll find that many car seat manufacturers make convertible seats with higher backs to accommodate your child for longer.

Each mode in a convertible seat (rear-facing, forward-facing, and booster) will have its own set of height and weight limits. When the child exceeds one of these limits (either height or weight), they have outgrown that “mode,” and you can move to the next one.

Your car seat manual will also state other criteria that will indicate when the seat is outgrown, such as harness strap placement and the buckle position.

Sometimes the ranges of acceptable height and weight for different modes (like rear-facing or forward-facing) will overlap. This means that the car seat manufacturer permits a child of that size and weight to use the car seat in either mode.

Experts still recommend keeping your child in each phase of the car seat as long as possible before moving to the next one.

Forward-Facing Car Seat Restrictions

Once your child outgrows the rear-facing limits on their car seat, they are ready to face forward. Your car seat manual will tell you when the seat is outgrown forward-facing by height and weight. Additionally, you’ll want to keep an eye on the position of the harness and headrest to see if your child is close to outgrowing the seat.

Proper positioning of the harness (when forward-facing) means that the harness straps reach the harness slot at or above your child’s shoulders. When the straps are on the highest slot and are no longer at or above the shoulders, it’s time to move to a booster.

Your child’s ears should also be below the top of the headrest when forward-facing.

The National Highway Traffic Safety Administration (NHTSA) recommends children use a five-point harness until they turn 7 years old.

A five-point harness is a very safe option for your child because it spreads forces from a crash over a wide area of the body, reducing the amount of impact at each point of contact. It also forces the child to sit in the proper position. In a booster seat, they have more freedom to wiggle around into potentially unsafe positions.

Booster Seat Restrictions

Booster seats are good for your child once they are at least 40 pounds. You’ll find that there are a few different styles of booster seats. Some are backless, and some have a high back. High-back booster seats give a little more support to younger booster riders and kids who tend to fall asleep in the car.

Many booster seats are made to accommodate children upwards of 100 pounds. The main point of the booster seat is to position your child so the seatbelt falls correctly across their body.

A seatbelt should lie firmly on the middle of your child’s shoulder, and the lap belt should sit low on their thighs (5). Ensure the seat belt is not twisted. Most booster seats also come with belt guides to help you get the correct fit.

Expired Car Seats

If you notice that the mysterious date printed on the side of your child’s car seat has passed, you need a new seat. Many people don’t realize that car seats expire, and you need to pay attention to their expiration dates.

Car seats expire for a few different reasons (6):

  • Materials break down over time: Car seats are primarily plastic. Over time, the constant temperature changes will cause the plastic to deteriorate as it’s constantly expanding and contracting. The metal of the car seat frame can also rust over time.
  • Wear and tear: Car seats go through a lot on a day-to-day basis. They’re constantly being taken out and reinstalled, and they’re subject to plenty of messes, both solid and liquid, speeding up their deterioration over time.
  • Replacement parts stop being produced: After several years, car seat manufacturers stop making replacement parts for certain seats.
  • Safety standards change: Safety standards are constantly evolving to ensure your child’s safety. With these changing standards, some older car seats may no longer meet all of the safety guidelines.

Car Accidents

You’ll also want to consider switching car seats if you get into an accident. If you have been involved in a car crash that was moderate or severe, you will need to purchase a new seat (7).

However, there are some instances where the seat may be usable even after a crash, and this would be the case for some “minor” accidents. A minor car accident can be classified as the following:

  • Any accident where the driver was able to drive away from the crash site.
  • The door nearest the car seat was not hit or damaged.
  • No passengers sustained any injuries.
  • Airbags were not deployed.
  • There is no visible damage to the car seat.

If all of the above statements about your car accident are true, it would be identified as “minor.” Some car seat manufacturers still require you to replace your car seat even after a “minor” crash, so always check your manual.

If you have any doubts, play it safe, and contact a CPST (Child Passenger Safety Technician) near you. They should be able to help you draw a conclusion.

How to Properly Dispose of the Old Car Seat

So what do you do with the old car seat when you get a new one? Some big-box stores, like Target, have a few “trade-in” events throughout the year. This is where you bring your old seat to be recycled and they give you a discount on new gear.

If you don’t take advantage of a trade-in event, you can recycle or dispose of the seat yourself. However, there are specific steps to follow to do it correctly.

  • Locate your nearest recycling center: Ask your local recycling center whether they accept car seats and how they would like to receive them. Find a center that accepts car seats here.
  • Check if they accept plastic from car seats: Call the center and ask for their specific guidelines for car seats. Some may want you to just bring the naked frame, and others may want it completely broken down first.
  • Remove the cover and any foam padding: These aren’t recyclable, so they can go right in the garbage.
  • Cut and remove the harness straps: These will also need to be thrown away.
  • Separate the metal from the plastic: Depending on your recycling center’s guidelines, you may not have to do this. If you do, you’ll probably need a screwdriver to take it apart.

If the seat can’t be recycled, it should still be broken down to the bare base and have “UNSAFE” or “EXPIRED” written clearly on it. This will deter anybody from picking it up from the garbage.


What are the 4 Car Seat Stages?

The four car seat stages are: 1) Rear-facing, 2) Forward-facing with a harness, 3) Booster seat, and 4) Seat belt.

Do Car Seats Go By Weight or Height?

Car seats go by both weight and height. Always check both criteria in your car seat’s manual to ensure your child fits safely.

How Do I Know If My Baby Has Grown Out of the Infant Car Seat?

Your baby has grown out of the infant car seat when they exceed the weight or height limit specified by the manufacturer or the top of their head is less than one inch from the top of the seat.

Should a Child’s Head Be Higher Than the Car Seat?

No, a child’s head shouldn’t be any higher than the car seat when rear-facing. For forward-facing, ensure the car seat provides proper head support.

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Medically Reviewed by

Kristen Gardiner, CPST

Kristen Gardiner, CPST is a writer, wife, and mother to three boys. Kristen became certified as a Child Passenger Safety Technician by Safe Kids Worldwide in 2015 and loves to volunteer and help educate parents about car seat safety. She has a passion for all things related to child safety.