Booster seat guide: when to switch, high-back vs backless, and belt fit
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- High-back booster seat. Best for: Children who just outgrew a harnessed seat. See options on Amazon
- Backless booster seat. Best for: Older children in seats with head restraints. See options on Amazon
- Combination harness-to-booster seat. Best for: Kids not yet ready for a belt-positioning booster. See options on Amazon
High-back vs backless booster
| Detail | High-back booster | Backless booster |
|---|---|---|
| What it does | Raises the child and positions the belt; may come with belt guides | Boosts height so the belt fits |
| Head and neck support | Has a back | None |
| Where it can be used | Back seat with a lap-and-shoulder belt | Only in seats with head restraints or high seat backs, with a lap-and-shoulder belt |
From NHTSA's How to Install a Booster Seat page. Both types are used only with a lap-and-shoulder belt.
When is a child ready for a booster?
NHTSA's recommendations by age:
- 4 to 7 years: keep the child in a forward-facing car seat with a harness and tether until they reach the maker's top height or weight limit. Then it is time for a booster seat, still in the back seat.
- 8 to 12 years: keep the child in a booster seat until they are big enough to fit in a seat belt properly.
NHTSA also says not to rush. Some younger children outgrow the harness limits but are not ready to stay seated correctly in a booster with the lap and shoulder belt; if so, look for a harnessed car seat with higher height and weight limits. Some harnessed seats convert to a booster once the child outgrows the harness; follow the instructions for converting it.
How to use a high-back booster
- Read the booster's manual and the child restraint section of your vehicle owner's manual.
- Place the booster in the back seat and make sure it sits flat on the vehicle seat.
- Have your child sit in the booster.
- Pull the seat belt across the child's body and buckle it.
- Use the seat's belt guides, if it has them, to position the belt.
- Adjust the lap belt so it lies snugly across the upper thighs, not the stomach.
- Adjust the shoulder belt so it rests across the chest.
- Check the belt fit often.
The seat belt fit test
The point of a booster is belt fit, and the same fit tells you when the booster is no longer needed. NHTSA says a seat belt fits properly when:
- the lap belt lies snugly across the upper thighs, not the stomach
- the shoulder belt lies snugly across the shoulder and chest and does not cross the neck or face
NHTSA says to check the fit of the seat belt often, and every booster and vehicle is different, so check it in each car your child rides in. If the shoulder belt cuts across the neck or the lap belt rides up on the belly without the booster, your child still needs it. Children should still ride in the back seat after they move out of a booster, NHTSA says, because it is safer there.
Safety tips for boosters
- Buckle it in when empty. NHTSA says booster seats should always be secured in the vehicle even when the child is not in it; an unbuckled booster can be tossed around and injure people in a crash or sudden stop.
- Back seat. Keep children in the back seat at least through age 12.
- Register it. Send in the registration card or register on the maker's website to get recall and safety notices. You can also sign up for NHTSA recall alerts.
- Get help. Car seat inspection stations have certified technicians who will check your setup, usually for free.
After a crash
NHTSA recommends replacing car seats after a moderate or severe crash. A seat does not automatically need replacing after a minor crash, which NHTSA defines as one where the vehicle could be driven away, the door nearest the seat was not damaged, no passengers were injured, air bags did not deploy, and there is no visible damage to the seat. Always follow the manufacturer's instructions.
For younger children, see our infant car seat guide and convertible car seat guide.
What to look for when you buy
High-back booster seat
Best for: Children who just outgrew a harnessed seat
NHTSA describes high-back boosters with belt guides that help position the belt.
Watch out: Check the maker's height and weight range for your child.
See options on AmazonBackless booster seat
Best for: Older children in seats with head restraints
NHTSA says backless boosters raise the child so the belt fits correctly.
Watch out: No head or neck support; use only where the vehicle seat has a head restraint or high back.
See options on AmazonCombination harness-to-booster seat
Best for: Kids not yet ready for a belt-positioning booster
NHTSA says some seats convert to a booster once the child outgrows the harness.
Watch out: Follow the maker's steps to convert it.
See options on AmazonQuestions people ask
- When can my child use a booster seat?
- After they reach the top height or weight limit of their forward-facing harnessed seat, per NHTSA.
- When can a child stop using a booster seat?
- When the seat belt fits: lap belt across the upper thighs and shoulder belt across the chest, not the neck or face.
- Can a child ride in the front seat in a booster?
- NHTSA says keep children in the back seat at least through age 12.
- Is a backless booster safe?
- It is designed to boost height for belt fit, but has no head support; use it only in seats with head restraints or high backs.
- Should I buckle an empty booster seat?
- Yes. NHTSA says an unbuckled booster can be tossed around in a crash.
Sources
- Car Seats and Booster Seats (nhtsa.gov), National Highway Traffic Safety Administration
- How to Install a Booster Seat (nhtsa.gov), National Highway Traffic Safety Administration
- Car Seat Use After a Crash (nhtsa.gov), National Highway Traffic Safety Administration