Booster Seats

Booster Seats

A guide to when to start using them and when to stop.

A child needs to be AT LEAST 4 years old, over 15kg and able to sit upright and not move around or lean out of their seat, to safely begin using a highback booster seat, but preferably should have completely maxed out their previous seat which would have a weight limit of between 18-25kg and so they would be much more likely to be older and mature before moving and so would undertand the potential dangers of not sitting properly. A childs pelvis does not begin to fuse together into solid bone until around 4 years old and so the risk of the seatbelt riding up onto the delicate abdominal area and causing internal injuries is increased as well as the possibility that they may end up ‘submarining’ under an adult seat belt! Don’t be tempted to move into a booster just because they’re taller than average or wearing larger clothes as their internal development won’t be any different to a smaller child of the same age. Always make sure you have exhausted all the options of keeping them harnessed, and preferably rear facing, before moving to a booster.

Many people regard the day that their child no longer needs to use a child seat as a milestone that they are growing up and can now sit in the car like an adult. This is where there’s a problem! Children are not mini adults as their skeleton is still developing and so allowing them to sit in the car without any additonal protection is dangerous. Vehicle seat belts are designed for adults over 150cm, therefore a booster seat should be used until the child reaches that height.

Unfortunately, the law in the UK states that a child who reaches 135cm or turns 12 years old, whichever happens first, no longer has to use a child seat. If you have a tall child on the 98th percentile, this can be as young as 7 years old! Although they may be the height of an older child and wearing older sized clothes etc, they do not have the bone structure and so by not having the correct protecion, they run the risk of more serious injuries in a collision.

Another thing to think about it where they should travel in the vehicle. Many people think that just because they’re able to use the adult belt then they’re safe to travel in the front of the car. This is not the case. When travelling forward facing in any seat, children are much safer in the rear seat until they no longer need to use a booster or are over 12 years old. It’s a good idea to check your owners manual too as this will tell you whether the manufacurer has approved the use of boosters or to have young children in the front seat, whether the airbag needs to be left on or switched off and the position of the front seat.

Try to buy the best booster seat you can afford as it’s likely that this stage of seat will be used for the longest length of time. Some also have isofix which is useful if your car has that feature as it means the booster will always be held in place, even when it’s not being used. If you have a non isofix booster, they’re just as safe for your child but you will need to remember to buckle the seat belt across when not on use or remove it from the car to prevent it becoming a potential projectile in the event of an accident or heavy braking. Some boosters also feature an additional point of contact for the lap belt to ensure it remains in the optimum position over the pelvis.

Legal vs Safe 

In the images above we can see the differnce using a highback booster can make;

Jack is 10 years old and 135cm so ‘legally’ he could travel in the car without a booster, however;

In the left picture we can see that when he’s sat on the vehicle seat with no additional protection, the shoulder belt is resting across his neck and not sitting evenly over his chest and the lap belt is resting across his stomach area. Both these positions could result in serious injuries to his neck, chest and internal organs . Therew is also nothing stopping his head coming into contact with the side of the car should the car be involved in a side impact.

In the right picture we can see the shoulder belt taking a safe path across the middle of his chest down toward his hip and the lap belt is istting over the top of his thighs. This position will allow the lap belt to ‘catch’ on his pelvis in the event of a collision - one of the strongest parts of the skeleton. His head is now well protected with the headrest surrounding his head and neck, minimising excess movement.

In the images above we can see the differnce using a highback booster can make;

Jack is 10 years old and 135cm so ‘legally’ he could travel in the car without a booster, however;

In the left picture we can see that when he’s sat on the vehicle seat with no additional protection, the shoulder belt is resting across his neck and not sitting evenly over his chest and the lap belt is resting across his stomach area. Both these positions could result in serious injuries to his neck, chest and internal organs . Therew is also nothing stopping his head coming into contact with the side of the car should the car be involved in a side impact.

In the right picture we can see the shoulder belt taking a safe path across the middle of his chest down toward his hip and the lap belt is istting over the top of his thighs. This position will allow the lap belt to ‘catch’ on his pelvis in the event of a collision - one of the strongest parts of the skeleton. His head is now well protected with the headrest surrounding his head and neck, minimising excess movement.


Before setting off on your next journey, go through the above steps to ensure your child really is travelling as safely as possible.

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