Stage 3: Booster Seats

Booster seats are for children over 18 kg (40 lb.). Don’t be in a hurry to move a child to a booster. It is safer for a child to use a 5 pt.harness as long as possible, up to the car seat’s maximum weight or height limits as indicated in the instructions. Newer models of car seats can be used with the harness up to 30 kg (65 lb.).

A booster seat is not a substitute for a car seat for children under 18 kg. If your child is too tall for his or her current car seat but does not weigh 18 kg (40 lb.), move your child to a Child/Booster seat that is appropriate for his or her height.

Newer booster seats have an upper weight limit of 45-54.5 kg (100-120 lb.) to allow children up to 9-12 years-of-age to travel safely.

Why does a child need a Booster Seat?

child with belt on incorrectlySeat belts are designed to fit adults, not children.

If the shoulder belt rides across a child’s neck or the lap belt is across a child’s stomach, he or she can be injured in a sudden stop or collision.

The shoulder belt should never be tucked under the child’s arm. In a collision, this position could break a child’s ribs and damage internal organs.

The shoulder belt should never be put behind a child’s back. Then, the upper body is unrestrained and the lap belt may rise above the hip bones. This could cause severe or fatal abdominal injuries in a crash.

illustration of proper sitting heightTo fit most shoulder belts, both safely and comfortably, a child needs to be at least 1.45 cm (4 ft. 9 in.) tall or have a sitting height of 74 cm (29 in.).

Until 9 or 12 years-of-age, a child’s pelvis is underdeveloped, making it difficult to maintain correct lap belt positioning over the upper thighs.

If a child’s thighs are shorter than the vehicle seat cushion and the feet don’t touch the floor, this will promote slouching, causing the lap belt to ride up over the stomach. If this occurs, there is a risk of serious internal injury or spinal damage in the event of a crash.

girl with proper seatbelt positioningA booster seat allows a child to safely use the adult seat belt by positioning it properly over his or her body – shoulder belt in the centre of the chest and lap belt on the upper thighs.

A booster seat will also raise a child so that he or she can see out of the car window. This can, in fact, increase safety – a happy child makes a better passenger, and is less likely to fuss and distract the driver.

Choosing a Booster seat:

If the back seat of your vehicle has lap and shoulder belts, you may choose either a Backless Booster or a High Back Booster. In addition, there are Built-in Booster seats that some vehicle manufacturers offer in a few of their models. There are also car seats that become booster seats after 18 kg (40 lb.).They are Infant/Child/Booster seats (also called 3-Stage seats) and Child/Booster seats (also called 2-in-1 or Combination seats).

If you only have lap belts in the rear seat, your child must use the seat belt alone. Currently, there aren’t boosters available that can be used with a lap belt alone.

Never use pillows, cushions, blankets, etc. instead of a booster seat. In a collision, they will compress leaving seat belt loose. The belt could then ride up on the child’s body, or the child could fly out of the belt altogether.

Remember to fill out and mail the registration card that comes with the booster seat. If there is a recall, the manufacturer will be able to contact you.

Backless Booster

backless booster seat
A backless booster is a covered, hard seat, with two “arms” or guides to keep the belt from sliding upward in a collision. It must be used with a lap and shoulder belt. Most models have adjustable straps to help position the shoulder belt. When using a backless booster, it is important that the child has proper head and neck support. The vehicle seat or headrest needs to come above your child’s ears when he or she is sitting in a backless booster, in order to provide adequate head support. If it doesn’t, a high back booster, designed to be taller than the vehicle seat, should be used.

High Back Booster

A high back booster must be used with a lap and shoulder belt. Most models can beclekoobr taller than the vehicle seat and provide head support when the seat back is low. Check the manual. A built-in guide helps position the vehicle belt in the centre of the shoulder and chest.

Many models have adjustable backs that can ‘grow’ with your child. A number of high back boosters are designed to be converted into backless boosters by detaching the backrest.

Built-in Booster

built in booster seatSome vehicle manufacturers offer built-in booster seats in a few of their models. They must be used with a lap and shoulder belt.The vehicle seat or headrest needs to come above your child’s ears when he or she is sitting on the built-in booster. Information on how to use the built-in booster seat is in the vehicle owner’s manual.

Using a Booster Seat:

Read and carefully follow the instructions that came with your booster seat and your vehicle owner’s manual.

The back seat of the vehicle is the safest place for a child. Transport Canada recommends that all children 12 years and under sit in the back seat. All booster seats need a lap and shoulder belt. If the centre, rear position has a lap and shoulder belt, this is the preferred place for a booster seat. It is likely the furthest away from the point-of-impact from any direction. If only a lap belt is present, then one of the side seating positions should be used.

A booster seat must not be installed in a front seating position that has an active air bag. For side-impact air bags, follow your vehicle manufacturer’s instructions. Clear the area between the booster seat and the door of all objects.
No more than 20% of the bottom of the booster seat should overhang the vehicle seat.
The seat belt should be snug on your child. There should be no more than one finger width between the seat belt and the child’s chest. Encourage your child to sit up straight. A child slumped over the side of a booster seat could be injured in a sudden stop or crash.

Ensure that the interior of your vehicle is safe. Tie down or lock all objects in the trunk. Items left on the rear window ledge can fall on a child. Items on the seat, on the floor, or in an open hatchback, wagon or van can fly around, if there is a sudden stop or collision.

photo of buckled booster seat

Remember to buckle in the booster seat when it is not in use. During a sudden stop, the empty booster could fly around the vehicle injuring the driver or other passengers.

When has a child outgrown the Booster Seat:

A child has outgrown a booster seat when he or she reaches the upper weight or height limit, or when the top of the ears is above the back of the vehicle seat, headrest or high back booster. [Note: For some models, the manufacturer indicates that the child’s head should remain in the centre of the booster’s headrest. Check your instructions.] Your child may not yet be ready to move to the seat belt alone. A different booster may be needed.

When to move to the Seat Belt alone:

The key to using a seat belt safely is positioning. If the belt is not worn correctly, a child can suffer brain or spinal injury, or damage to vital internal organs in a crash. It is not safe for a child to use the seat belt alone until all six (6) of the points below are met. Provincial and Territorial legislation differs. Check your regulations as to what the law is for anyone transporting children.

A booster seat should be used until:

a child properly in a booster seatThe child is 9 to 12 years-of-age,
The child is at least 1.45 cm (4 ft. 9 in.) or has a sitting height of 74 cm (29 in.),
The child can sit all the way back against the vehicle seat with knees bent comfortably over the edge of the seat, feet on the floor,
The lap belt rests across the upper thighs,
The shoulder belt is centred on the shoulder and chest, and
The child can stay seated like this for the whole trip.


Click here to download a pamphlet on Booster Seats
Click here to download a One Minute Booster Seat Safety Check
Click here to download a One Minute Seat Belt Safety Check