When to Transition Car Seats: A Comprehensive Guide

Michelle Pratt
September 12, 2024
8 min read
Follow us on social!
A little boy sitting on the floor next to a measuring tape

When you look up the right time to transition car seats, a lot of what you get are the legal requirements for moving kids from seat-to-seat. However, if you’ve been with us for any length of time, you know that what’s “legal” is not always safest. Think about a state that doesn’t require helmets when riding motorcycles. Of course, we know that even though it’s not legally required to wear a helmet, you still increase the risk of death by 37% when you’re not wearing one.

So, when you’re looking at when to transition through the car seat stages, don’t look for the earliest legal opportunity to transition and go with that. Instead, go with what’s safest! If you’re not sure what’s safest, you’ve come to the right place. Today, we’re delivering an easy-to-follow guide that tells you when you should transition your child from one car seat to another. 

Here’s what you need to know:

When to Transition Car Seats: A Comprehensive Guide 

If you’re looking for a certain age to move your kids to a new seat, we’re sorry to say that you’re not going to find that answer! Car seat transitions are actually not based on an age, despite car seat laws seeming to support that misconception. We can definitely approximate how old your child might be when it’s time to move up, but what’s actually important is your child’s size, proportions, and their specific seat. 

As a rule, you’re going to move up in a car seat based on the manual’s noted limits. So, a child will stay in that car seat until they max out one of the weight or height limits noted on the seat. That means some children will be able to stay in certain seats longer than others. It also means that a child will likely be in their designated seats much longer than what’s legally required—and that’s okay! We’re about being as safe as possible, not just avoiding a traffic ticket. 

But, if you’re still confused, don’t worry—we’re going to get more specific! Below, we’ve laid out how you’ll know when your child is ready to move out of each car seat stage. 

Infant Car Seats (Birth to Around 1)

Infant Car Seats

An infant car seat, or infant carrier, is a seat made specifically for newborns and infants. It’s the only car seat type where you can remove the seat from the base and carry it around for easy baby transport! This car seat stage is not required, and you can actually start right out in a rear-facing car seat if you want. If you do choose to use an infant seat, your baby will likely outgrow it before they turn one. 

Here’s when you need to move your child out of the infant car seat and into a rear-facing car seat:

  • When the child reaches the max weight limits (usually between 22-35 lbs) 
    or
  • When the child reaches the max height limits (usually between 29-32 in)
    or
  • When the child’s head is less than one inch from the car seat shell 

Want more on this? Check out these posts:

When to switch from infant seat to convertible

Rear-Facing Car Seats (Birth to About 4+)

Rear-facing Car Seat
Convertible Car Seats

Once a child has outgrown an infant seat, it’s time to move to a rear-facing convertible seat/all-in-one seat. (Or, again, you can start out in a rear-facing convertible car seat.) Like an infant seat, this seat faces the back of the vehicle and includes a 5-point harness. However, it’s not portable and has much higher weight and height limits. The recommendation is to keep the child rear-facing until they reach the limits of the convertible car seat that you have.

Here’s when you need to move your child from a rear-facing car seat to a forward-facing car seat:

  • When the child reaches the max weight limits (between 35-55 lbs)
    or
  • When the child reaches the max height limits (40-49 in)
    or
  • When the child’s head is less than one inch from the car seat shell (There are some exceptions to this rule; check your manual.)
    AND
  • Your child is at least 2 years old

Want more on this? Check out these posts:

Why rear-facing is safest

Front-Facing Car Seats (Ages 4 to 5+)

Convertible Car Seat
Convertible Car Seat
Forward-Facing Only Car Seat
Forward-Facing Only Car Seat

The next stage is a front-facing car seat! Often, if you have a convertible car seat, you’ll be using the same seat but in “front-facing mode.” This is a seat with a harness that faces the front of the vehicle. As your child grows, they still need the support of that harness for quite a while, so ensure your child is mature enough to move on to a booster before you transition to using one.

Shoulder Strap Height
Shoulder Strap Height

Here’s when you need to move your child out of the harnessed car seat and into a booster seat:

  • When the child reaches the max weight limits (usually between 40-65 lbs) 
    or
  • When the child reaches the max height limits (usually around 49 in)
    or
  • When the child’s shoulders are above the highest available harness slots
    or
  • When the child’s ears are above the car seat shell

Want more on this? Check out this post:

Should I buy an all-in-one car seat?

Booster Seats (Ages 5 to 12)

High-Back Booster
High-Back Booster
No-Back Booster
No-Back Booster

The last stage of the car seat journey is the booster seat! Belt-positioning boosters prop your child up so that the seat belt fits correctly on their body. Many parents move out of this stage too early because they don’t realize how an incorrect fitting seat belt can prevent it from keeping your child safe in a crash. Don’t rush out of this phase even when your 11-year-old tells you that none of their classmates use a booster. What’s safest is always best! 

Here’s when you can move your child out of the booster seat:

  • When the child passes the 5-step test
    1. The child sits all the way back against the vehicle seat
    2. The lap belt lies flat across the upper thighs, not the stomach
    3. The shoulder belt crosses the center of the child’s shoulder and chest
    4. The child’s knees can bend over the edge of the seat without slouching 
    5. The child can stay seated upright without reminders 

View this post on Instagram

A post shared by Michelle | Car Seat Safety (@safeintheseat)

Want more on this? Check out this post:

Your kid will be in a car seat for 10+ years!

You can’t transition kids by age and laws. Move your child through the car seat stages based on the facts!

What is your best bet for when to move your kid from one car seat phase to the other? The manual. The car seat manufacturer will clearly lay out the limitations of the seat. You should continue using those seats until you reach one of the weight, height, or other maximums. This will ensure your child stays safe in their seat for every ride, no matter their age! 

Car Seat Finder
Discover the perfect car seat for your child at the best price with our Car Seat Finder Tool—personalized recommendations, safety ratings, and unbeatable deals all in one place!

For more trusted information on car seat and vehicle safety, head over to the Safe in the Seat blog! We have need-to-know info as well as hundreds of car seat reviews and recommendations. With us, you can have peace of mind on every drive.

As an Amazon Associate, Safe in the Seat earns from qualifying purchases.