A booster seat helps keep children safe when they have outgrown their car seat but aren’t ready yet for a seat belt alone. Booster seats lift the child’s body so that the seat belt fits around him or her properly.

Children who use a booster seat in the back seat of the car are 45% less likely to be injured in a collision than children who use just a seat belt, according to Safe Kids Worldwide.

Types of booster seats

A high back booster seat provides support behind your child’s head. High back booster seats are recommended if your car has low seat backs and no head rests, or for younger children who may fall asleep in the car, so they can lean their heads against the side of the seat.

A backless booster seat may be more convenient for carpools or travel but should only be used in vehicles with high seat backs to support your child’s head. A seat back is high enough if your child’s ears are just below the top of the seat or head rest.

When to use a booster seat

Your child should use a booster seat after he or she has outgrown the weight and height limits of a forward-facing car seat.

It’s also important to think about whether your child is mature enough to stay in the booster seat during the entire car ride, with the seat belt properly fitted across his or her shoulder and below the hips.

Children are typically between the ages of 8 and 12 before they are ready to use a seat belt without a booster seat.

Making sure a booster seat fits properly

Booster seats don’t need to be installed like car seats do, because your child’s weight on the booster seat will hold it in place, while the seat belt keeps your child secure. 

When your child is in the booster seat, the seat belt should lie flat across his or her chest, on the bony part of the shoulder (away from the neck) and low on the hips or upper thighs. 

Make sure your child doesn’t place the shoulder belt under his or her arm or behind the back. If your child is uncomfortable with the seat belt placement, use a car seat with a harness or a different booster seat that has an adjustable shoulder belt guide.

You should secure the booster seat with a seat belt when you’re not using it so it doesn’t fly around the car if you have to stop suddenly. Some booster seats also come with hooks similar to lower anchor hooks. While these can be secured to the lower anchors of the vehicle, they do not substitute for the seat belt to secure the child. They simply hold the booster seat in place and the child will use the seat belt normally if in this type of a booster seat. 

When to move to a seat belt

To be sure your child is ready to stop using a booster seat, perform a seat belt fit test. Check that:

• Your child’s feet touch the floor and knees bend at the edge of the seat when his or her back and bottom are against the seat back. 
• The lap belt fits snuggly across your child’s hips or upper thighs.
• The shoulder belt fits across the shoulder and chest, not across the face or neck.

This video from Safe Kids Worldwide shows what to look for when performing a seat belt fit test.

Safe Kids Florida Suncoast, led by Johns Hopkins All Children’s, is a coalition of community organizations and partners committed to preventing injuries in children and adolescents, including car seat and booster seat safety.