More to measure: What you need to know about car restraint height

By Britax

With a little one growing faster and faster each day, we know that it’s important for you to choose products that will fit your child for as long as possible. That’s why we encourage you to focus on your child’s car restraint height and weight rather than age when shopping for a new car seat.

The importance of height to get it right!

The maximum weight and height capacity are commonly used as a guide for how long your child will fit in a car seat, but many children will actually outgrow the seat by seated shoulder height before reaching the maximum height or weight capacity. In both rear-facing and forward-facing mode, the position of the harness straps on your child’s shoulders and the position of your child’s head within the car seat are the key factors that determine when your child has outgrown a car seat. Both of these measurements are related to your child’s seated shoulder height.

Shoulder height markers

To help you monitor your child’s fit in their car seat, Britax have included Shoulder Height Markers on all of their car seats. These markers act as a guide to let you know how much room your child has left to grow and when it’s time to look for their next child restraint.

How to measure your child's seated shoulder height

Since children’s torso lengths can vary significantly from child to child, even when children are the same height, it’s important to measure to have a better understanding of how long your child will likely fit in a car seat. To measure your child’s seated shoulder height, follow these simple steps:

  1. Sit your child on the floor against a wall.
  2. Place a ruler or straight object across the top of their shoulder to mark the height.
  3. Measure up from the floor to the top of the shoulder marker to get an accurate seated shoulder height measurement.

Graduating to the booster seat

When your child has outgrown the car restraint height limit (when they have grown past the top shoulder height marker) of their current car seat, it is time to move them into a booster.

Just like babies, older children are at risk of serious injury in the event of a vehicle accident, which is why a safety tested booster seat is essential for ensuring proper protection of your child when driving.

The taller the better when it comes to transitioning to an adult seat belt

Graduating from a booster seat to an adult seat belt is not a transition that should be rushed! In fact, often children are moved into an adult seat belt way too early! Consider moving your child out of their booster seat after they have exceeded the height recommendations and can no longer sit comfortably in the restraint. Their height is the key indicator and you should also consider how they sit in the seat.

In assessing how your child sits in an adult seat, Britax suggest you consider the following:

  1. If your child’s legs are shorter than the depth of the seat and do not hang comfortably over the seat edge, your child is likely to move forward or slump in their seat which will change the position of the lap belt and increase the risk of serious injury.
  2. If the seat belt crosses your child’s face or neck rather than their chest, your child is likely to place the seat belt behind their back to remove this discomfort greatly increasing the risk of injury.
  3. If the lap belt rides up over your child’s abdomen when sitting correctly, your child is at increased risk of serious injury (the lap belt should always be positioned over the hips and thighs).
  4. If your child wriggles or slumps in their seat, the lateral support provided by a booster seat reduces the risk head, neck and abdominal injury.

DO wait to move your child to their next seat - It is important not to graduate your child from a convertible car seat to a booster seat too early as unfortunately, the results can be devastating.

DON’T move your child to an adult seat belt too early – Children are often moved into an adult seat belt way too early. Britax recommend that you only consider moving your child out of their booster seat after they have grown past the shoulder height markers and more than 145cm in total height.

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Note: The views and advice expressed on this blog post are those of the author and are not representative of the Pregnancy Babies & Children's Expo.

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