When Is My Child Ready for a Booster (and Then a Seat Belt)?

Move your child to a booster only after they outgrow their forward-facing harness, and to a seat belt alone only when the belt fits correctly, usually around 4 feet 9 inches tall and between 8 and 12 years old. Fit, not age, is what really decides.

Reviewed by Jessie, our on-staff certified Child Passenger Safety Technician.

The four stages, in order

Children move through four stages: rear-facing, then forward-facing with a harness, then a booster, then the adult seat belt alone. Keep your child in each stage until they outgrow it, and do not rush to the next one.

From harness to booster

Keep your child in the forward-facing harness until they reach the seat's height or weight limit, which on most modern seats is well past age 4 and well past 40 pounds. Move to a booster only once they have outgrown the harness and are mature enough to sit properly for the entire ride.

From booster to seat belt: the 5-Step Test

Your child is ready to use the seat belt without a booster only when they pass all five:

1. Their back is flat against the vehicle seat.
2. Their knees bend comfortably at the front edge of the seat.
3. The shoulder belt crosses the middle of the shoulder and chest, between the neck and the arm.
4. The lap belt sits low and snug across the upper thighs, not across the stomach.
5. They can stay seated this way for the entire trip.

One more rule

All children younger than 13 should ride in the back seat.