You should move the straps up to the next slot when your child's shoulders are above the current harness height. For rear-facing seats, the straps should be at or just below the child's shoulders. Once you turn the seat forward-facing, the straps must be at or just above the shoulders. This isn't based on age but on your child's physical development, so checking every few months is crucial for safety.
The correct harness height ensures the car seat can properly restrain your child's body in a crash. If the straps are too low when forward-facing, your child could be thrown upward and out of the seat more easily. Conversely, straps that are too high in a rear-facing position won't hold the child down into the seat shell effectively.
Here’s a quick reference for when to make the adjustment:
| Scenario | Correct Strap Position | Key Indicator to Check |
|---|
| Rear-Facing | At or just below the shoulders | Child's shoulders are level with or slightly above the current strap slots. |
| Forward-Facing | At or just above the shoulders | Child's shoulders are level with or have slipped below the current strap slots. |
| General Rule | Adjust with growth | Check fit every time you change the child's clothing (e.g., from summer to winter wear). |
| Maximum Height | Follow manufacturer limits | Do not use the seat if the child's shoulders are above the top strap slots. |
| Proper Fit Test | Pinch the shoulder strap | If you can pinch a horizontal fold in the strap at the collarbone, it's too loose. |
A good habit is to do a quick check every month or whenever you notice your child’s clothes fitting differently. The "pinch test" is also essential: after buckling the child in, try to pinch the harness strap vertically at their shoulder. If you can pinch any excess webbing, the harness needs to be tightened. Proper strap height and tightness work together to keep your child secure.
