How to Strap a Booster Seat Into the Car

Booster seats are a step between harnessed child safety seats and using a regular car seat belt 1. Most children fit into a booster seat at age 4, or 40 lbs., whichever comes first.

Laws vary according to state but all require children to be well-protected. According to New York State's Occupant Restraint law, children ages 4 to 7, and those under 4 but over 40 lbs. must use a child restraint system.

In 2008, according to the National Highway Traffic Safety Administration (NHTSA) there were 214 passenger vehicle occupant fatalities in the age group of 4 to 7. "Among the 197 fatalities in this age group for which restraint use was known, 78 (40%) were unrestrained," according to the NHTSA.

Booster Seats with Back Support

Assemble the booster seat and back support, if not previously assembled.

Position in car's back seat so that it rests firmly against the back. Ensure the head rest doesn't push it forward. The booster seat should not hang over the seat of the car at all.

Put your child in the booster seat so that the child's back is flat against the back.

Pull down on the car's shoulder belt and place it in the shoulder belt guide on the side of the booster seat closest to the car door. This is the small opening built into either side of the head rest.

Pull the lap belt over the child's thighs making sure it is underneath the arm rests on the booster seat.

Push the belt latch into the safety buckle of the seat belt 11. Tighten both the lap and shoulder belts to make them secure.

Adjust the head rest if necessary. Your child's shoulders should be equal with the bottom of the head rest.

Booster Seats without Back Support

Assemble the booster seat if not previously assembled.

Attach the shoulder belt positioning clip to the back of the booster seat. Find the vertical bar in the back of the seat and insert the loop end of the strap around it. This should be positioned on the side of the shoulder strap to be used. Push the clip and strap through the loop and pull tight.

Put the booster seat in the car, tight against the back of the car seat. Ensure the positioning clip is clear and not under the seat.

Place your child onto the booster seat, ensuring that her back is pressed firmly against the back of the car.

Pull the seat belt so the shoulder strap lies across her chest and the lap belt rests on her thighs.

Push the belt latch into the safety buckle of the seat belt 11. Tighten both the lap and shoulder belts to make them secure.

Slide the positioning clip through the shoulder belt portion of the seat belt. Pull up or down on the cinching strap to adjust as necessary.


Read the instructional manual that came with your booster seat. Specific directions may vary by manufacturer.

Children under 12 should always sit in the back seat of a car.

Make sure the shoulder belt is across the center of the shoulder and chest; it shouldn't rest on the neck. The lap belt shouldn't sit on the stomach; it should be low on the hips or high on the thighs.


Never place the shoulder belt under a child's arm or behind his back. This could lead to serious injury or death in a crash.

Booster seats should always be used with a lap/shoulder belt combination; never with just a lap belt.