How Tight Should Car Seat Straps Be?

Car accidents are one of the leading causes of injury and death in children, so it’s important to get the fit of your baby’s car seat right from the start. Here’s how to keep your little one safe and comfortable on the road.


After nearly two weeks in the NICU, our twins were nearly ready to come home. The last thing standing in their way? The car seat test. They’d have to be strong enough to sit upright and straight in their car seat for over an hour while their vitals were monitored.

They passed with ease, and it also gave us the chance to sit down with a nurse and talk about how to properly fit our babies into their car seats.

But not everyone gets that thorough of a sit-down, and many parents wonder exactly how car seat straps and buckles should fit. As your little one grows, it’s even more difficult to update and adjust the straps to keep up with their physical changes.

The National Highway Traffic Safety Administration estimates that nearly 60 percent of all car seats aren’t used correctly, and many of those issues stem from car seat straps being too lose or not adjusted properly.

Our neighbors to the north, the Canadian Paediatric Society, estimates that 80 to 90 percent of car seats aren’t used properly.

It’s not enough to simply use a car seat: your baby must be properly fitted to the seat in order to keep him or her safe and secure. Many parents don’t realize that in a car accident, rear-facing babies are pushed upward in their seat because of the angle of the seat and the momentum of the vehicle.

If a baby isn’t strapped the right way, this can cause too much movement in the car seat, which may lead to organ damage, internal bleeding and other injuries.

Car seats reduce the risk of death by 71 percent in infants and 54 percent in toddlers, says the CDC. You can keep your baby even safer by making sure their straps are just the right tightness.

Here’s how to do it.

The Pinch Test

With your child strapped into the car seat, try to pinch together the fabric of the straps above the center chest buckle. If there’s enough loose strap that you can pinch the fabric together, the car seat is too loose.

If you can’t pinch the fabric together, then the straps are most likely tight enough. Use your best judgment to make sure your child has enough room to breathe: tight straps are good, but you don’t want them constricting to the point that your child is uncomfortable or has difficulty breathing.

Previously, the rule of the thumb was the “two fingers test,” which said that you should be able to fit two fingers between the car seat strap and your child’s chest, but this was resulting in straps that were looser than they should have been.

Now, the pinch test is considered the standard measurement of tightness for many parents and professionals, and it’s a good rule of thumb to consider when adjusting your child’s car seat. And because straps can change their adjustments due to clothing or your baby’s movement, it’s worth doing the pinch test before every drive.

how tight should carseat straps be

Overall Car Seat Fit

Secure car seat straps are helpful, but the rest of the car seat should fit appropriately as well to keep your baby as safe as possible. Here are a few things to consider when buckling up your youngsters:

  • Keep the chest buckle/restraint at armpit level
  • Make sure none of the straps or buckles are twisted
  • Always use straps and buckles, even for short rides
  • Avoid puffy outerwear that can compress in an accident

Last, the American Academy of Pediatrics (AAP) recommends keeping the shoulder straps for rear-facing babies at or below the shoulders, and forward-facing children should have the straps at or above the shoulders.

car seat straps tightness rear facing
Source: Rear Facing Toddlers

This helps reduce the risk of excess movement during a car accident. As your child grows, be sure to pay attention to when the car seat’s slots need to move up or down depending on their size and position.

Why Car Seat Fit is So Important

Car seats may seem like a great way to keep your baby safe, but the truth is that car accidents are still one of the leading causes of death for kids between 1 and 13, says the NHTSA.

leading causes of death in the us by age group
Source: CDC

One of the best ways to ensure your baby’s safety is to use a car seat that’s appropriate for their size and weight, and to stick to the guidelines set out by the manufacturer.

how tight should car seat straps be
Source: CDC

This might seem like common sense, but the fact is that these simple guidelines are often overlooked. One study found that nearly 40 percent of 17- to 19-month olds weren’t in rear-facing seats, despite the fact that “children in a forward-facing seat are five times more likely to be seriously injured than those in a rear-facing seat,” according to the AAP.

When babies aren’t properly strapped into their car seats, the chance of being seriously injured or even ejected from their seat is increased. And when the rest of the car seat isn’t properly fitted, injuries can occur related to the chest buckle.

The center chest buckle, which should be placed at the armpit level of your child, can cause serious injury if it’s placed too low.

In this case, the buckle caused a bruise on the child’s chest, but if it was placed lower, which is a common mistake, it could have led to even more severe injuries. Some people believe that a too-low chest buckle can cause internal injuries, which may be possible, but the biggest threat to kids is that a low chest buckle doesn’t keep the shoulder straps in place as well.

“The REAL danger of a too low clip is that it might allow the harness to be too widely spaced at the shoulders,” says Car Seats for the Littles. “This could lead to increased head excursion, spinal, internal, and brain injuries, or even ejection from the car seat.”

So it may seem like a small thing to consider, but the tightness of your baby’s car seat straps and the position of things like the chest buckle can make a huge difference in you were to get in a car accident. Ensuring a proper car seat fit is the best way to stay safe on the road, and it’s worth the half-minute it takes to adjust your baby’s straps with each ride.


Brandon Young

Brandon is an amazing dad to twin toddler daughters and a preschooler son. He enjoys taking his family to new destinations and exploring. When not writing the world’s best parenting articles, he enjoys hiking, cooking, and spending time with his wife and kids.

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