When Can You Move Your Child to a Booster Seat?

Car seat experts answer parents' most common questions about booster seats so that you can make smart, informed—and most of all—safe choices for your little one.

Boy in a car booster seat

Sally Anscombe / Stocksy

If your child seems to be outgrowing their car seat, you might be wondering if it's time to move them to a booster seat. Information about booster seats can be confusing. Which instructions do you follow? Should you wait to move your child? How do you know if your kid is ready?

We reached out to car seat safety experts to answer parents' most common questions about booster seats so that you can make smart, informed—and most of all—safe choices for your little one.

What Are Booster Seats?

Booster seats are a type of car safety device that a child graduates to after outgrowing a forward-facing harnessed car seat. Booster seats are secured in your car with a seat belt that is placed across your child's chest and hips. Unlike rear and forward facing car seats, booster seats do not have a harness that buckles your child into the seat; instead, the seat belt secures your child. According to the Academy of American Pediatrics (AAP), booster seats reduce a child's chances of injury by 45%, as compared to using a seat belt alone.

There are four types of booster seats:

  • Booster seats with high backs
  • Booster seats with no back
  • Combination seats, which transition from a forward-facing harnessed seat to a booster seat
  • All-in-one seats, which can transition from rear-facing, to forward-facing, to a booster

Booster Seat Weight and Height Requirements

Different booster seats will have different weight and height recommendations, so the first thing to do as you consider when to move your child to a booster seat is to check the instruction manual. You should also check the instructions of the forward-facing car seat your child is currently using to determine if they may have outgrown it. Most forward-facing car seats can accommodate a child up to 65 pounds, with some able to accommodate a child up to 70 to 90 pounds.

Whatever the case, the Academy of American Pediatrics (AAP) urges parents to keep their children in forward-facing car seats as long as possible, because the harness on these seats offer optimal protection. Brittany Kaiser, public health educator with Safety Stop at St. Louis Children's Hospital agrees with this assessment. "It is recommended to move a child to a booster seat once they have maxed out the height OR weight limit of their 5-point harness car seat," she suggests.

Signs Your Child Is Ready to Move to a Booster Seat

It's not just height and weight requirements to watch for when it comes to making the switch to a booster, says Kaiser. "Maturity is a huge factor in deciding if your child is ready to transition into a booster seat," she says. Here's why: when your child is in a 5-point harness, they are restrained, whereas when they are in a booster, there's only a seatbelt holding them in place.

"They now have the ability to slouch down in their seat, lean over and play with siblings, reach down or slide out to get a toy that has fallen, etc.," Kaiser says. "If they are not sitting in the booster seat correctly, the seatbelt cannot do its job at protecting them." Moving your child into a booster requires a major leap in maturity, Kaiser says. She suggests having conversations with your child about what this responsibility means, and the fact that you need them to stay seated correctly in their booster.

Jennifer McCue, injury prevention coordinator at Nemours Children's Hospital in Delaware says that for kids to ride safely in a booster, they should be able to sit upright with the seat belt fitted properly for the entire ride. "Children should never play with the seat belt, put the shoulder belt behind them, under their arm, or unbuckle it during the ride," she describes.

When Can You Move Your Child to a Booster Seat?

Beyond the recommendations for your particular booster seat, there is no magic age that a child should be moved to a booster. "Every child is different," says Kaiser. "It is usually safer to keep a child in their 5-point harness car seat until they have outgrown it." However, there are some criteria that she uses as a minimum for when it's acceptable to move a child to a booster:

  • They should be at least 40 pounds
  • They should be at least 40 inches tall
  • They should be at least 4-years-old

You should also look at how the seatbelt is fitting your child when they are using a booster, says Kaiser. "The seat belt lap portion should be over the top of their thighs or very low on the hips, never on the stomach," she describes. "The shoulder belt goes across the middle of the shoulder, never on the neck." Either way, if you have a wiggly child, Kaiser says, you should keep them in a forward facing car seat until they are more mature.

Should You Wait to Switch?

McCue agrees with the AAP's stance that children should remain in forward-facing car seats as long as possible, up until the manufacturer's height or weight limit. "When they have outgrown the car seat, children should transition to a booster seat using the vehicle's seat belt," McCue says. "Since kids are too small to use a seat belt alone, the booster seat helps 'boost' them up, so the seat belt fits them correctly." When buckling your child into their booster, McCue says you should make sure the lap belt lies over their lower hips and the shoulder belt is positioned across the center of your child's shoulder and chest.

How Long to Use a Booster Seat

Once your child has transitioned to their booster, you might want to know how long you should keep them in one. Just like it's best to keep your child in a forward facing car seat as long as possible, it's best to keep them in a booster for as long as you can, says Kaiser. "Do not be eager to transition into or out of the booster too soon," she recommends. "We see lots of children who are moved out of a booster seat and sitting in a vehicle seat with only a seatbelt far too soon."

Keep in mind that seatbelts were designed for adults, not children, Kaiser emphasizes. This means that your child should be as close to adult-size as possible before ditching the booster. "They need to be in a booster seat until they are 4'9", can sit straight with their back against the vehicle seat and knees bent at the seat edge naturally, and the seatbelt should sit on their hips and their shoulder properly," she says.

Usually kids need to be in booster seats until they are about 8 to 12 years old, according to the AAP. That might seem like a long time, but when it comes to kids and safe safety, it's always best to err on the side of caution. After all, car crashes are a leading cause of death among kids aged 1 to 13, so taking proper safety precautions in a car is a must. If you have any further questions about booster seats or car seat safety in general, please reach out to a pediatrician or car seat safety technician.

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