To know if a car seat’s harness is tight enough, it must pass the pinch test. Adjust the harness, then try to pinch the webbing in three places:
- at the child’s hips
- at the child’s torso
- at the child’s collarbone
If you can grasp any material and pinch the harness vertically between your fingers, it’s too loose. Keep making small tugs on the harness adjuster until your fingers slide right off the webbing.