Using the Car Seat Harness Correctly

car seat harness

Learning to use the Car Seat Harness correctly is important as various incorrect usage are four of the most common car seat mistakes parents make.

After selecting the right car seat for your child’s car seat stage (selection) and installing it (direction, location and installation) — and preferably having that installation checked by a certified Child Passenger safety Technician, there is harnessing.

From birth to booster you are likely using a 5-point harness car seat. This means the car seat harness system contacts your child in five points: both shoulders, the hips and the crotch. These are the strongest points of the body. A 5-point harness spreads the crash force evenly over the child.

First thing first, which way is your child facing?

harness slotsIf your child is in a rear-facing car seat, the harness strap should be at or below your child’s shoulders. If your child is in a forward-facing car seat, the harness strap should be at or above your child’s shoulders.

Make sure the harness straps are both going through the car seat — shell and cover — at the same level and neither strap has any twists in it.

Once your child is in the car seat.

harness strap pinch testPull the harness straps over your child and buckle the harness and close the chest clip.

Pull the harness straps to a snug tightness. This means if you try to pinch the harness horizontally you cannot pinch the material together. This is the “pinch test.”

Move the chest clip to armpit level.

That seems simple enough, right?

Except that as mentioned, harnessing mistakes account for four out of ten of our most common car seat mistakes.

Those mistakes include:

1. Not having the harness straps snug enough.

A large number of parents still leave the harness too loose. At checkups we often hear them say something like, “it seems too tight and uncomfortable.”

A snug harness as: “A snug strap should not allow any slack. It lies in a relatively straight line without sagging. It does not press on the child’s flesh or push the child’s body into an unnatural position.” You want the straps to be “as snug as a hug.”

most common car seat mistakesWhy is this so important? During a crash the harness straps are holding the child in the car seat. If those straps are too loose, the child will not be properly secured and could even come out of the straps becoming an unrestrained child.

2. The chest clip is not at armpit level.

In many car seats the chest clip is meant to break during a crash, so how can the position be so important? Well, too low and the harness straps may not be positioned correctly on your child’s shoulders, especially if the straps are also too loose. In this case, the clip prevents the straps from separating, ensuring your child is not ejected during a violent crash. Too high and prior to breaking, it could compress on your child’s throat.

3. Harness straps are not properly positioned for the child.

For rear-facing child safety seats, if you are looking at the child sitting in the seat the straps should be going through the safety seat at the slot at or below the child’s shoulder. In other words, you should not be able to see the strap coming out of the seat above the shoulder, it should be hidden beneath the child’s shoulders.

Download our report: Common Car Seat Mistakes and How to Fix Them

In a forward crash ­— the most common type of crash — the first motion is going to be the top of the child seat rotating down toward vehicle’s floor. If there is enough crash energy, the child’s body is going to try to slide toward the top of the child safety seat. You want the harness straps to be cradling, or at least very close to the child’s shoulder, so that they do not slide “up” into and stop suddenly or even go through the neck opening when they finally hit the misplaced straps.

For forward-facing car seats, the harness straps should go through the safety seat at or above the child’s shoulder. Think about how our seat belt is positioned on us. It anchors above our shoulder so that we lean into it in a forward impact.

4. Harness straps are not routed correctly through the car seat.

Why is this so important? The car seat manufacturer crash tested your car seat and meant for the straps to be used in a certain configuration. If you routed the straps incorrectly, it could interfere with the performance of the car seat during a crash. If the car seat harness straps are twisted, they may not distribute the weight correctly and cause injury.

Also remember, to not have anything thicker than sweatshirt material between your child and the car seat harness straps. This includes thick winter coats, blankets and those nice fuzzy, plush car seat covers that have a back section between the baby and car seat.

Get a visual of car seat safety rules.

We want to know, were you nervous to “over tighten” the car seat harness straps when you first started putting your child in a car seat? Share your comments below.

By Amie Durocher, Creative Director at Safe Ride 4 Kids and certified CPS Tech since 2004

Copyright 2019 Safe Ride 4 Kids. All rights reserved. You may not publish, broadcast, rewrite or redistribute this material without permission. You are welcome to link to Safe Ride 4 Kids or share on social media.

We originally published this post in January 2017. We updated the article for accuracy and comprehensiveness.


© amie durocher
© amie durocher
© amie durocher
  • Debbie Chapin
    Posted at 08:26h, 26 March Reply

    I have seen people tighten the straps so much that it was very hard to fasten and was pressing down a lot on the child’s shoulders. What harm can this be to the child’s posture or spine.

    • Amie
      Posted at 11:41h, 26 March Reply

      Hi Debbie, We could see that over tightening harness straps for a rear-facing child or a forward-facing child where the harness straps are incorrectly placed behind the shoulders instead of above the shoulders may impact the spine. Though we have not seen any studies or reports to this affect. More often than not, the harness straps are not any where near tight enough. Quite often parents feel that properly tightened harness straps are over tight. So it could be a matter of perspective. You could recommend to these people that they visit with a certified CPS technician who can check the tightness of the straps to see if they are just right or too tight.

  • Amber Rae
    Posted at 18:27h, 10 June Reply

    My toddler keeps moving the chest clip down to his belly. I can’t get it to stay at armpit level, is this a problem with all car seats or just mine? It’s a Costco brand.

    • Amie
      Posted at 13:20h, 11 June Reply

      I can’t think of a brand in the US where the chest clip doesn’t move so it would be a problem with all brands if that is what your child likes to do. There is a product by Merritt Manufacturing (they produce car seats for children with special needs) that would help keep the chest clip in place. You can find that here:

  • Praveen Boodhoo
    Posted at 23:37h, 18 November Reply

    How do I get a toddler in and out of the car with no coat on during minus weather conditions? The only way I’m thinking is to remove the coat when being placed in the seat and putting on when coming out

    • Amie
      Posted at 13:54h, 19 November Reply

      Yes, that is what we would recommend. The child should have a coat going to and from the car but not in the car seat. Take the coat off, buckle in and adjust the straps, then put the coat on backwards over the straps. Do the reverse when getting out.

  • Megan Bachman
    Posted at 23:35h, 21 November Reply

    Are there any stats that you are aware of that prove that correct usage of a car seat harness can decrease risk of injury or death vs poor car seat harness usage? Wanting to share the importance of “correct buckling” with family and hoping some stats will help prove the importance of taking the time to buckle them in right! Thanks in advance!

    • Amie
      Posted at 15:51h, 23 November Reply

      I don’t know of any statistics specific to correct car seat harness use. On a quick search I couldn’t find any numbers but there is this quote from the Guardian which tested various common car seat mistakes: “Hynd, who works as an adviser on car seats to the European Commission and represents the UK on working groups for child seat safety, said this would have resulted in head injuries. She said the slackness of the harness would have prevented the seat spreading the force of the crash over the child’s body and reducing injury. “Too much slack in the harness means that the child will be caught later in the crash, because the harness doesn’t have time to absorb the energy,” she said. In some cases, it can even result in the child being ejected.”

  • Diana Westcott
    Posted at 23:59h, 13 April Reply

    I am trying to find out where to position the harness covers?? I’ve tried looking it up and looking in the owner’s manual. I have a Graco and my daughter is 1 month old in the rear facing seat. The car seat comes with harness covers and I don’t know where they’re supposed to be on shoulders all the way up below, etc… and why can’t I find the answer if they come with the car seat?!?! Makes me wonder…

    • Amie
      Posted at 14:27h, 14 April Reply

      Are they sewn on or detachable? Usually they are supposed to be up by the neck. In some seats, the manufacturer says not to use them for a newborn. Which Graco seat do you have? For instance, Graco SnugRide ClickConnect 35 just briefly says some models come with inserts to be used for extra support and comfort and has a picture that includes the harness strap cover on page 25 but I couldn’t find any specifics written any where else.

  • Kerry Skinner
    Posted at 11:22h, 28 May Reply

    If a child is too big for a 5 point harness carseat and is put in one anyways what harm can this do to the child if a wreck was to occur.

    • Amie
      Posted at 11:28h, 28 May Reply

      If the child is bigger than the specifications noted on the car seat, there is potential the car seat could fail in a crash thereby not actually restraining the child. I’m not sure any manufacturer has crash tested their car seats with a larger than specified crash test dummy to determine what would/could happen.

  • Leslie
    Posted at 16:55h, 15 October Reply

    Good solution for children who like to unbuckle or move chest clip would be to button a button up shirt over the car seat!

  • Dawn Spillane
    Posted at 11:56h, 26 February Reply

    My daughter is 16 days old. Im trying to get the straps that go across her hips, to be tighter. Either those don’t tighten or something is awry. Any thoughts on this?

    • Amie
      Posted at 12:27h, 26 February Reply

      Hi Dawn, Try pulling the straps from around her hips up so the slack is by her shoulders before tightening the harness straps down.

  • Bridgite Lakies
    Posted at 22:08h, 07 March Reply

    Ok so snug as a bug I get that. But what about so snug it hurts the child’s (boy) privates? My sister ALWAYS makes my son’s that snug and tells him he is lieing and to get the f over it. I’m concerned because that area is very sensitive

    • Amie
      Posted at 17:16h, 09 March Reply

      Hi Bridgite, Check and see if you can adjust the crotch strap on your seat. Many seats have different settings so as the child grows it can moved further out. The crotch strap should be at or in front of the crotch area. Perhaps if you can adjust that it won’t hurt that area even when it’s pulled nice and snug so it passes the pinch test.

  • Sandra E
    Posted at 09:59h, 14 July Reply

    Hi! My daughter gets the crotch buckle to poke into her stomach. I’ve tried repositioning and adjusting straps to no avail. If a picture will help I can provide one via email.

    • Amie
      Posted at 08:29h, 15 July Reply

      Some more information (seat, child’s age, weight, height) and a picture would be helpful. Please use the contact form and we’ll send an email you can reply to with a picture.

  • Kristin S
    Posted at 18:56h, 26 August Reply

    How can I keep the hip straps from pinching the skin on my child’s legs? I’m am so careful each time but it always manages to get pinched near the side of the buckle.

    • Amie
      Posted at 13:53h, 27 August Reply

      I can’t say I’ve ever encountered this problem or I’m not understanding fully. Do you mean when you are buckling the 5-point harness, it is pinching her legs? Are you pulling the harness tight before buckling? I recommend leaving the harness strap loose when buckling, then pull it tight (so you cannot pinch the strap as shown), then adjust the chest clip.

  • Cindy Sanders
    Posted at 12:53h, 18 October Reply

    How tight should the harness straps on the child’s chest be. Our grandson screams every time he is in his car seat. Could it be too tight? He is 7 months old.

    • Amie
      Posted at 13:17h, 22 October Reply

      Hi Cindy, The harness straps need to be tight enough that you cannot pinch the webbing as seen in the photo above. It’s possible it could be too tight but there could be other reasons he screams in his car seat. Some children just don’t like any confinement; some children could be irritated by a tag in their clothing that only seems to bother them while in their car seat. At 7 months he obviously can’t explain why he’s upset. If you think the straps are too tight, you can try loosening them as long as they remain tight enough that you cannot pinch the webbing.

  • Mike Longshore
    Posted at 16:01h, 15 March Reply

    My wife is always untightening and tightening the straps every time we take my daughter in and out of the car. Should we not just set the tightness where we want it, and then all we have to do is buckle and unbuckle each time?

    I’ve seen numerous articles about shoulder strap positioning, but where should the lower straps be resting?

    • Amie
      Posted at 18:12h, 15 March Reply

      Hi Mike, Many parents find it easier and more comfortable for the child to get the child in and out of the seat by loosening the straps.

      About which lower straps you are asking? The harness straps are all one piece. The lower part should be at the child’s hips/thighs. The vast majority of seats do not have any adjustment on that part of the harness strap. Some seats do offer adjustment of the crotch strap. If that is the strap you are referring to, it should be in the slot closest to the child’s groin.

  • Hannah Kuijpers
    Posted at 03:52h, 26 March Reply

    Hey !

    Thank you so much for these great tips.
    I will definitely follow these instructions. Keep writing.


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