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How to Fit a Kids Bike Helmet

I was just going thru some photos of my son biking and found myself cringing.  In many of the pictures his chin strap is too loose, or his helmet is tilted ever so slightly to one side.  Now that Little P has learned how to buckle his own helmet, he keeps loosening the straps so that it is easier for him to do.  It is a constant battle to keep his helmet properly tightened.

So while I can’t proclaim that my own child always wears his helmet correctly, I can tell you how it should be done and how important a properly adjusted helmet is.

Step 1: Make sure the helmet is the right size.

It seems obvious, but I see lots of kids wearing helmets that aren’t even the right size.  There is no way to adjust a helmet to make it fit if it is way too big (or small) for the kid.

To size your child for a helmet, you want to measure their head circumference.  You can do this with a cloth measuring tape or using a string.  Measure around their forehead, just above the eyebrows.  Make sure to measure in centimeters (or convert to centimeters after the fact).

You can then compare this measurement to the helmet manufacturer’s sizing table and pick an appropriate helmet for your child (or verify that their current helmet fits).

If for whatever reason you can’t physically measure the child (for example, maybe you’re a grandparent buying the helmet as a gift), you can use the below table as a general guideline.

AgeHead Circumference (in cm)
12 months46
2 years48
3-5 years51
6-10 years53
11+ years56

Step 2: Make sure it is snug.

Helmets are designed to last for a while which means variable sizing.  To make sure the helmet fits your child, it will come either with multiple helmet pads or a fit ring (or both).  With skate-style helmets, you generally have to rely on padding.  Other cycling helmets will have a “universal fit ring” at the back of the helmet that tightens or loosens the helmet.

The helmet is appropriately snug when your child can shake and roll their head without the helmet shifting.  The front should be aligned just above your child’s eyebrows (that same place where you measured their head circumference).  If it is tilted backward and you are seeing large expanses of their forehead, it is either too large or needs to be tightened.

Helmet positioned too far back
This helmet is titled too far backward. Photo credit.

At this point, I also like to ask the child how it feels.  As parents we are often eager to make sure it is REALLY tight, but you also don’t want it so snug that it hurts.  If the helmet is uncomfortable, the child won’t want to wear it.

Step 3: Adjust the side straps.

The straps on either side should come to a Y just below your child’s ear.  I generally find this easiest to accomplish by adjusting it while they have the helmet on their head.  That is, if they will stay still long enough for you to do it.  Good luck, mom!

Side straps appropriately adjusted
This helmet is fit perfectly! Photo credit.

Step 4: Adjust the chin strap.

Tighten the chin strap so that it is snug but not excessively so.  You should be able to fit one finger between the strap and your child’s chin, but no more.

Chin strap too loose
The chin strap here is too loose. Photo credit.

Depending on the design of the helmet, there might be some extra length of strap just hanging out.  If this happens, I like to trim the strap so that there is 6 inches or so remaining, and then fasten the remainder in place with a rubberband.

Step 5:  Keep checking.

Adjusting your child’s helmet once isn’t enough.  If your kiddo is like mine, they will tug on the chin strip until it loosens and play with the fit ring on the back of the helmet.  Keep an eye on the fit.  Is the chin strap loose?  Is the helmet crooked on your child’s head?  If so, it’s time to tighten things back up.  I make sure to do this a couple times a month, and more often if needed.

Other helmet safety tips

  • If the helmet has been in a crash, or if it has been dropped, then it needs to be replaced. Even if there are no visible signs of damage, the integrity of the helmet may be damaged.
  • Teach your children to treat their helmets kindly. To the point above, if your kid throws their helmet or lets it carelessly fall to the ground, the helmet is getting damaged and won’t be as effective in a crash.
  • Check the helmet for visible signs of wear. I was recently looking at one of my son’s helmets and noticed there was a crack in the foam!!  Time to throw that baby out!
  • My favorite helmets for kids are ones with MIPS-technology. These are more expensive but provide superior protection.
  • If your child is into multiple sports (skateboarding, skiing, etc) don’t just assume their existing helmet will work for biking too. Make sure that it has a CPSC label certifying it for use on a bicycle.
  • Store the helmet indoors. Extreme temperatures (both hot and cold) can damage the helmet.  You also want to keep it away from direct sunlight.
  • We all know kids are dirty. To clean a bike helmet, use warm water and mild detergent.  Avoid soaking the helmet or exposing it to high heat.

Now That You Know How to Fit a Helmet, Choose The Best One For Your Child

5 thoughts on “How to Fit a Kids Bike Helmet”

  1. Your third bullet point in the ‘Other helmet safety tips’ is something I am hesitant to agree with. If there’s a crack in the helmet you say ‘throw that baby out’. Seems a bit harsh. Maybe keep the baby and spend money on a new helmet :).

    Great, helpful article. Thank you!


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