The state of California legally requires children under the age of 8 years old and under 4’9” (57”) to be secured in a booster seat.
Children over the age of 8 years old may (and should) be secured in a booster seat until they reach 4’9” (57”).
Booster Seat Requirements California
According to the laws on booster seats in California, child passengers must ride in a booster seat (or forward-facing car seat) until they reach ONE of the following requirements:
- Booster Seat Age: 8 years
- Booster Seat Weight: undeclared
- Booster Seat Height: 57” (4’9”)
Children under the age of 8 years old OR under 4’9” are legally required to be secured in a booster seat (or forward-facing car seat) in the backseat.
Children 8 and over, or taller than 4’9”, may wear only a seatbelt, but it is recommended children under 4’9” continue to use booster seats until they reach 4’9” in height to prevent injury from standard seatbelts.
Where can I get my booster seat checked or installed in California?
All California Highway Patrol (CHP) offices have child passenger safety technicians who can assist you in installing car seats and booster seats.
Many fire stations and health care agencies in California have child passenger safety technicians on staff as well.
General Booster Seat Laws FAQ
Are booster seats effective?
According to the CDC, “booster seat use reduces the risk for serious injury by 45% for children age 4-8, when compared with seat belt use alone.”
When can a child use a booster seat?
A child can use a booster seat when she outgrows her forward-facing car seat with a harness.
Though the laws on front-facing car seats and booster seats differ by state, for safety’s sake your child should stay in a front-facing (harnessed) child seat until he reaches the maximum height or weight on the seat.
When can a kid stop using a booster seat?
The minimum safe height for use of a regular seat belt without a booster seat is 4’9”.
Due to this, it is recommended your child ride in a booster seat until they are at least 4’9” tall, regardless of their age.
Not all state laws support this.
Many states (including California) have minimum ages at which children may transition to regular seatbelts, no matter how tall they are.
But if you want your child to be the safest they can be on the road, you should keep them in a booster seat until they reach 4’9”.
What is the booster seat weight limit?
Different booster seats have different weight limits, typically 100-120 pounds.
But weight isn’t the main determiner of when a child should move from a booster seat to a seat belt.
Height is more important to a seat belt’s fit.
That said, your child should never ride in a booster seat once they exceed the weight limit.
The seats are designed to be safe only for those under the maximum weight.
So, if your child has outgrown the weight limit on their booster, upgrade them to a booster with a higher weight limit or make the transition to a regular seatbelt.
What’s the best booster seat?
The best booster seat is the one that will do the most effective job of keeping your child safe in the event of an accident.
According to Consumer Reports, the top-performing booster seats on the market (as of February 2023) are:
Graco Turbobooster Grow
Peg Perego Viaggio Shuttle Plus 120
But you don’t have to buy a separate booster seat if you have a convertible car seat.
For convertible toddler-booster seats and all-in-one car seats with booster functionality, see our car seat buying guide Which Car Seat To Buy: Making Sure Your Little Ones Stay Safe On The Road.
When were booster seats invented?
The very first child seats for cars were more booster seats than car seats.
They were literally designed to “boost” children up so they could see better (and so parents could see them), but they had no built-in safety features.
Booster seats as we know them today, with their focus on transitional safety between car seats and seatbelts, have only been around since the late-1990s to early 2000s when laws requiring them started being implemented.
When did booster seats become mandatory?
Booster seats are not mandatory in all states.
Some states have younger minimum ages and no height requirements for transitioning children from child seats to seatbelts.
In those states, children can typically move directly from forward-facing car seats to regular seatbelts.
As for the states that do have mandatory booster laws, the first laws (Tennessee and South Carolina) went into effect in 2001.
Bridging the Gap Between Car Seats and Seatbelts
Car seats are designed to protect the smallest of children, while seatbelts are only safe for children over a certain height (4’9”).
Booster seats bridge the gap between the two.
While booster seats are not legally required in California if your child is over 8 years old, for safety’s sake we recommend ignoring the minimum age requirement and keeping your kid in a booster until they reach 4’9”.
Prior to that, follow California’s laws regarding car seats.
And, once they graduate from a booster, follow CA’s front seat laws for when your child can legally sit in the front seat (age 8).
Or, better yet, follow the CDC guidelines and buckle them up safely in the backseat until age 13.
For more on California’s car seat laws, see California Car Seat Laws.
For more on California’s front seat laws, see California Front Seat Law.