When to Change Car Seats, According to a CPS Technician

You will need to change your child’s car seat when they have outgrown it. As a general rule of thumb, you will know when your little one has outgrown their car seat when: 

  • Your child hits the maximum weight limit OR
  • Your child hits the height limit 

Us parents know that changing car seats isn’t as straightforward of a process as it seems. When to change car seats will depend on your little one’s age and weight, the type of car seat you have, the car seat you plan to switch to and more. 

To help us break down everything we need to know about this common milestone, we interviewed Child Passenger Safety Technician, Jessica Choi

Car Seat Stages 

The four car seat stages with pictures for each stage

To understand when to change car seats, it’s important to know the four different car seat stages.

1. Rear-Facing 

Rear-facing is the first car seat stage starting from birth. Jessica recommends that kids remain in the rear-facing position for as long as possible. This is the safest position for kids because it protects their necks in case of a crash. 

Jessica says that “most kids will use an infant car seat until they outgrow it, then a convertible seat in the rear-facing position until they reach the upper weight or height limit.” 

Signs your child has outgrown the rear-facing car seat

  • If your child's head is within an inch of the top of the shell of their car seat, they have outgrown that mode of the seat
  • When your little one reaches the upper weight or height limit of their rear-facing convertible seat

Jessica warns that “many parents turn their child forward-facing prematurely because they are worried about their child's legs being too long and their feet touching the vehicle seat. It's perfectly safe for your child's feet to touch and for their legs to hang out of the car seat.” 

Good to Know: Many states have updated their child passenger safety laws to require rear-facing until at least two years old. To check the laws of your state, visit the Governors Highway Safety Association

2. Forward-Facing With a Harness 

We know it’s tempting to switch to a forward-facing seat early so you can see your tiny human’s cute face while you drive, however, Jessica says to only turn your car seat around to forward-facing once your little one has outgrown the limits on your rear-facing convertible car seat. This is the safest way to do things and will protect your kiddo in case of any accidents. 

Always check your seat's limits as it's dangerous to exceed them. “These limits vary by seat, but most seats accommodate forward-facing kids until sometime around 3-6 years,” says Jessica. 

Signs your child has outgrown the forward-facing car seat

  • When they reach the forward-facing weight and height limits
  • They are at least four years old and weigh at least 40 lbs 

Good to Know: If your child outgrows their harnessed seat before they are old enough and big enough for a booster, you'll need to get another forward-facing car seat with a higher harness limit. Always check with the manufacturer regarding maximum height and weight limits for your child's seat.

3. Booster Seat 

Once kids have outgrown their forward-facing harness, it's time for a booster seat. Some convertible car seats come with a booster mode. If not, you will need to purchase a booster seat. 

Booster seats are an exciting next step because they are typically easier to get in and out of, are much lighter for us parents to move around and they can help your kiddo feel like a “big kid.” Jessica says to “keep kids in their booster until they fit properly in a seat belt without it. Be sure to follow your state's law and don't get rid of the booster too soon.” 

Signs your child has outgrown the booster seat

  • They pass the five-step seat belt test (below) 
  • They are old enough. Most kids will be between 10-12 years old before they can safely fit in a seat belt without a booster

Five-Step Seat Belt Test:

a checklist of the 5 step safety questions to ask before moving your little one to a seat belt

Before your child moves to a seat belt, make sure they pass the test below. 

  1. Can your child sit all the way back in the vehicle seat, with their butt and back against the seat?
  2. Do their knees bend over the edge of the seat and their feet touch the floor?
  3. Can they remain seated in this position, without slouching, for the entire trip?
  4. Does the lap belt fit safely on their upper thighs, not across their belly?
  5. Does the shoulder belt fit safely across their collarbone, not across their face or neck?

Good to Know: Kids will fit differently in different vehicles. Your child may be able to skip the booster in a smaller sedan, for instance, but may still need a booster in a bigger car or SUV. 

4. Seat Belt 

If your child can pass the five-step seat belt test and they meet the minimum requirements for your state to stop using a car seat or booster seat, they're ready for the seat belt. 

Jessica reminds us that “seat belts are made for adults, so kids need to be tall enough to use them safely. Don't forget to check your state's law about booster seats to make sure you aren't getting rid of your child's booster too soon.” 

Good to Know: Make sure kids know to never place the shoulder belt under their arms or behind their backs.

Infant Car Seats 

Maxi-Cosi Mico XP Max Infant Car Seat, Sonar Plum, 2021


An infant car seat will typically be your baby’s first car seat. They should always be used rear-facing in your car. 

Infant car seats are usually compatible with a stroller of the same brand or a universal stroller frame and they often come with a carry handle and a detachable base. They are great for parents who are in and out of the car a lot because they double as a carrier making it easy to move baby back and forth. 

Similar to most car seat options, infant car seats can be used until a child reaches the weight or height limit. According to Jessica, “many babies will outgrow their infant seat sometime between 9 and 18 months, depending on their growth and the weight and height limits of the car seat. Some families might skip an infant car seat and go straight to a convertible seat, or choose to start using a convertible before their child has outgrown an infant seat. That's okay, just make sure the convertible seat has appropriate weight, height and developmental limits. There are a few convertible car seats on the market that require babies to have good head and neck control.”

Typical infant car seat weight limits

“Weight and height limits for infant car seats vary greatly, and parents should always check the label or the manual to find the limits for their car seat,” says Jessica. “Some infant seats have a weight limit as low as 22 lbs, or as high as 40 lbs.”

Our Recommendations: 

Shop Infant Car Seats

Convertible Car Seats 

Clek Fllo Convertible Car Seat, 2022

Convertible car seats are often the second car seat in a child's life, however, most of them are also suitable for newborns. Jessica says that most “children will move from an infant carrier to a convertible car seat (or will start off in an all-in-one-seat) which will start rear-facing and can be switched to the forward-facing position.” 

Unlike infant car seats, convertible car seats don't have a handle and can't be used as a carrier. However, convertible seats are popular because they can be installed rear-facing or forward-facing for different stages. According to Jessica, “most kids can easily rear face until they are about four years old in many convertible seats.”

Typical convertible car seat weight limits

For most convertible car seats weight requirements are up to 40-65 lbs. Always check with the car seat manufacturer to ensure your specific car seat limits. 

Our Recommendations

 Shop Convertible Car Seats

Booster Seat 

Britax Highpoint 2-Stage Belt-Positioning Booster Car Seat, 2018

When your little one is ready to transition out of a forward-facing seat with a harness, you will need a booster seat if your convertible car seat does not come with a booster mode. Booster seats raise your child so that the seat belt is properly positioned over them. 

According to Jessica, “many booster seats start at four years old but most car seat technicians will recommend waiting until at least age five to use a booster because at that age most children will be mature enough.” 

Typical booster seat weight limits

Your little one is ready for a booster seat when they have outgrown the weight or height limit of a convertible seat (which is typically 40-65 lbs). 

Most children are not ready to move to a seat belt until they are at least 4’9” and around 8-12 years old. However, always check the laws in your specific state to be sure. 

Our Recommendations

Shop Booster Seats

Car Seat Safety Tips & Facts 

Having your little one in the car with you is the definition of carrying precious cargo. So, it’s super important to understand car seat safety to keep them (and you!) safe the next time you head off. 

Here are Jessica’s top car seat safety tips and facts you should know

  • Do not leap to the next car seat stage too soon. It's fun to celebrate our kids' milestones and graduations, but with car seats, it's safest to delay moving to the next stage as long as possible. 
  • Keep kids rear-facing as long as possible: If kids are forward-facing too soon, their necks aren't strong enough to withstand the extreme force of a frontal crash and their spinal cords may stretch. 
  • To prevent hot car deaths, always ‘Look Before You Lock’: Check your back seat to make sure all kids and pets are out of the car before you walk away. And always keep your car locked, even in the garage, to prevent kids from gaining access and becoming overheated. 
  • Before taking off, make sure your child's car seat is installed tightly and correctly and double-check your little one is harnessed snugly in their seat. 
  • For babies, don't use their car seat as a substitute for a safe sleep environment. If baby is sleeping when you arrive home or to your destination, remove them from their seat and place them in their bassinet, crib or even in a safe place on the floor where they can be flat and on their backs.

What to Keep in Mind When Buying a Car Seat 

The right car seat is one that fits your child, fits your car and is one that you can install correctly every time. 

Here are some things you should consider before purchasing a car seat

  • What stage of car seat your child is in 
  • Your little one’s age, weight and height 
  • What direction they will be facing (rear or forward facing) 

Jessica says that “I have used so many car seats for my kids and for my patients. Some seats work better than others depending on what you or your child need. My recommendation is to try it before you buy it if possible. Go into a store and touch the car seats—make sure you like how the fabric feels and how the harness adjusts. Think about weight and height limits. If both parents are tall, it's probably a good idea to think about a seat with a higher height limit. If someone is pregnant with multiples, there's a higher chance those babies will be born a little smaller. Look for infant seats with a lower starting weight (4 lbs would be better than 5 lbs in this case).”

You'll be the one using this car seat every day of your life, so it’s important to make sure you love it! When it comes to safety, Jessica says that all seats meet the same crash test standard in the US, so you can feel safe choosing whichever one you like best. If buying a used car seat, make sure you follow the same safety standards. 

What to Do With Your Old Car Seat 

If you’re transitioning to a new car seat, your toddler has outgrown it or your car seat has reached its expiration date, it’s important to make sure you dispose of it properly. 

Here are a few sustainable ways to get rid of your old car seat: 

  1. Trade it in at a local retailer that accepts used or expired car seats: Both Target and Walmart have annual trade-in programs. 
  2. Hand it down: If your car seat is not broken, expired, recalled and has never been in a car crash or accident, you can pass it down to a family member or friend. 
  3. Recycle it: Many states have car seat recycling programs where you can recycle your old seat properly. 
  4. Donate it: Check with local thrift stores, consignment shops, shelters, churches and hospitals to see if they accept old or used car seats. 

For more information, read our guide to what to do with old or used car seats

Car seats are one of those big-ticket baby items every new parent needs. At GoodBuy Gear, we sell open box and gently used car seats. All gently used car seats go through a proprietary 30-point safety inspection process called the GoodBuy ™ Car Seat Safety Check. Learn more about that process and what you can expect here.

As parents, we know how important it is to make sure the gear we give our tiny humans is in clean, working condition. That’s why every item we sell (including car seats) goes through an in-depth inspection process

Before we go, Jessica’s last piece of advice is to make sure that you install your new car seat correctly. “Please reach out to a child passenger safety technician if you're having trouble with your car seat installation or if you'd like to have the installation checked. We're here to help you and we want to keep your kids safe!”

To find a technician near you, go to: www.cert.safekids.org

About Jessica Choi, CPSTI, STAC Instructor 


Jessica Choi, CPSTI

Jess is a child passenger safety technician instructor who loves helping families keep their kids safe. She also has lots of experience with kids who have complex healthcare needs and is happy to consult with families for all of their injury prevention questions.




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