How to Install a Booster Seat Correctly

LATCH (Lower Anchors and Tethers for Children) is the anchor system built into most vehicles and used by infant and forward-facing harnessed seats to secure the seat itself. Belt-positioning boosters work differently: the child is restrained by the vehicle's adult seat belt, not by the booster being anchored to the car.

Some booster models do have lower anchor connectors. Their job is narrower than it looks: they keep the booster from sliding around or becoming a loose object in a crash when no child is sitting in it. Read the manual before assuming a booster's lower anchors are doing more than that. If the instructions do not say the anchors restrain the child, they do not.

1. Read the booster's manual and the vehicle manual together. Confirm the seating position has a lap-and-shoulder belt, not a lap-only belt, unless the booster is specifically certified for lap-only use.
2. Place the booster on the vehicle seat. For a backless booster, confirm the vehicle seat back and head restraint reach above the top of the child's ears. For a high-back booster, adjust its own headrest to the child's height.
3. If the booster has lower anchor connectors and the manual calls for using them, attach them to keep the empty booster in place. This step does not replace the seat belt check that follows.
4. Sit the child in the booster, all the way back against the seat.
5. Pull the lap belt across the child's upper thighs, as low as possible, not across the stomach.
6. Route the shoulder belt through the booster's belt guide if it has one, so it crosses the middle of the shoulder and chest, not the neck or face.
7. Buckle the belt and remove slack. The child should not be able to slide the shoulder belt off the shoulder or pull the lap belt up onto the stomach.
8. Recheck belt position at the start of every ride, and again if the child has been moving, reaching, or sleeping.

The steps above are the same for both types; what changes is what the vehicle needs to supply. A backless booster has no head support or belt guide of its own, so it depends entirely on the vehicle seat: a head restraint or seat back tall enough for the child, and a shoulder belt anchor positioned so the belt naturally crosses the shoulder rather than the neck.

A high-back booster brings its own headrest, side wings, and usually a built-in shoulder belt guide, which is why it tends to be the safer default in vehicles with low seat backs, bench-style middle seats, or a shoulder belt anchor that sits too far forward or back for the child's size.

The most common errors are all belt-path problems, not assembly problems: a lap-only belt used where a lap-and-shoulder belt is required, the shoulder belt sitting on the neck or tucked under the arm or behind the back, the lap belt riding up onto the stomach, a backless booster used without real head support from the vehicle seat, and an unoccupied booster left loose when the manual says to secure it (a loose booster can become a projectile in a crash).

A less obvious one: reusing a booster from an older sibling, a hand-me-down, or a yard sale without checking its history. See the used-booster checklist below before putting a child in one.

• Find the manufacture date and any expiration or use-by date printed on the shell or a label, and confirm the booster has not expired.
• Search the model and manufacturer on NHTSA's recall lookup for any open recall.
• Inspect the shell, belt guides, and any anchor hardware for cracks, missing pieces, or a missing instruction label.
• Confirm you know it was never in a moderate or severe crash. If you cannot confirm that, do not use it. A booster's plastic and foam can be damaged in ways that are not visible after a crash.

Get help from a certified Child Passenger Safety Technician if the belt keeps crossing the neck or face, the lap belt keeps riding onto the stomach, the booster slides around even when properly placed, the vehicle seating position only has a lap belt, or you are not sure whether a forward-facing harness seat has truly been outgrown yet. A short in-person check can catch fit problems that do not show up in a photo or a general guide like this one.

Not sure if your child still needs a booster at all, or which type fits best? Use the seat finder, or run the 5-step belt fit test.