How to Measure for a Motorcycle Helmet – 2021 (Guide With Charts and Video)

| Last Updated: December 22, 2020

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Proper sizing for motorcycle helmets is incredibly essential. 

While proper sizing is necessary for all safety helmets, it’s especially crucial for motorcycle helmets because of the dangers you face (and the threat you pose to others) while driving. 

In this article, we’ll walk you through all of the things you need to know to invest in the proper helmet size. 

Head Shapes for Motorcycle Helmets

While human heads come in all shapes and sizes, there are three basic shapes of motorcycle helmets. They are:

Head Shapes for Motorcycle Helmets

“Round Oval” means your head is about the same size front to back as it is ear to ear. “Long Oval” means it’s longer from front to back than it is from ear to ear. “Intermediate Oval” falls somewhere in-between the two.

Even once you know your head type, you won’t be able to walk up to a helmet and tell what shape it is by appearance alone. The outside of a good motorcycle helmet doesn’t necessarily show the form it takes on the inside. 

You can measure your head from front to back and ear to ear to determine your head shape, but the easiest way to figure this out is to simply visit a helmet shop and try on all three types

Motorcycle Helmet Size Chart

The chart below will give you a better idea of how motorcycle helmets are sized (and what size you should fall under).  

Motorcycle Helmet Sizing Chart

Youth Motorcycle Helmet Size Chart

Youth motorcycle helmets are usually sized more generally than adults, but that doesn’t mean you shouldn’t take care while doing so. The youth helmet size chart below should help. 

Youth Motorcycle Helmet Size Chart

How to Size a Motorcycle Helmet

Measuring your head for a motorcycle helmet is easy to do once you know what you’re doing. The most important part of the process is measuring the size of your head. To do this, use a flexible measuring tape to measure the circumference of the widest part of your head - usually, an inch or so above your eyebrows. If you need a demonstration, please refer to the example video below. 

How to Measure Your Head For a Motorcycle Helmet

Once you’ve converted your head measurement into a helmet size using the chart above, it’s up to you to tweak the other aspects of the fit and decide whether or not that particular size is for you. How a specific helmet fits, such as whether it’s a little looser or a little tighter than usual, can vary by the helmet manufacturer. 

However, the size of your helmet isn’t all you’ll need. As we saw above, motorcycle helmets come sized for different head shapes, too. The head shape you choose can significantly affect the feel of your final result. For example, a small in a “Long Oval” helmet might feel just as big as a medium in a “Round Oval” helmet.

As you might expect, visiting a helmet shop and trying on a few helmets is valuable when identifying your best fit. However, if you can’t try on any helmets beforehand, the thing you want to look for most is a snug fit along with your crown - the same place you took the measurement before. 

If your helmet feels too snug around the front and back of your head, go for a longer, more oval shape; if it’s too tight on the sides of your head and loose on the front and back, size down to a rounder helmet. 

You may feel discomfort in other areas of the helmet, such as in your cheek pads, but don’t worry about that right away. You can change out much of the extra padding inside your helmet later to create your perfect fit. The most important thing is to invest in a helmet that sits snugly where it needs to for your safety. 

How Do I Figure Out What Size Motorcycle Helmet My Youth Needs?

Sizing a helmet for your child is the same as sizing one for yourself. Since child helmets usually come in fewer sizes, there are fewer options to pick from, but your final size also depends on how helpful your child is in describing the fit of their helmet. 

How To Measure a Child’s Head For A Motorcycle Helmet

To measure your child, simply take the circumference of their crown, then consult the child sizing list above. From there, you will need to ask your child about the fit or seek the help of a professional. Comfort is important, but the essential thing is to find a helmet that will keep your child safe and secure. 

You can refer to this video for extra guidance on how to size a motorcycle helmet:

Common Sizing Issues With Motorcycle Helmets

Several things might lead you to size issues while searching for the perfect motorcycle helmet. While motorcycle helmets have a pretty comprehensive sizing system for you to work from, it’s not always perfect. 

What If I Can’t Figure Out My Head Shape?

If you’re having trouble figuring out the shape of your head, likely, you fall somewhere in the “Intermediate Oval” in-between range. You may need to choose different forms based on which brand you shop from. 

Why Doesn’t The Helmet I Ordered Fit, Even Though I Followed The Sizing Guide?

The most common issue you’ll run into is sizing quirks between brands. Different manufacturers size their helmets differently, so even if you followed your usual size and head shape preferences, you could end up with something that doesn’t quite fit. This is why trying it on in person first is so vital. 

Manufacturing differences can be one reason why your helmet doesn’t fit, but a few others could cause it, too. Some of these include:

  1. Interior padding is too large/small

  2. The helmet rubs or pinches, making it too uncomfortable to wear

  3. Your glasses or hair accessories don’t fit under your helmet

If My Ears Fold When I Put My Helmet On, Is It Too Small?

To make things more complicated, a small amount of discomfort doesn’t necessarily mean that your helmet doesn’t fit correctly. For example, if your ears fold over when you put your helmet on, all you need to do is readjust or replace the ear padding inside your helmet.

My Helmet Is a Little Too Loose, How Do I Fix This?

You can adjust the padding in your helmet if it’s just slightly too loose or too tight - just make sure to make everything safe and secure before you venture out. 

Do Eyeglasses Affect The Size Of Helmet I Need To Buy?

Eyeglasses and other accessories can cause discomfort under your helmet, too. However, more often than not, you can alleviate this issue by buying different glasses. Any eyeglasses with thin or flexible arms tend to fit best under motorcycle helmets, but as a last resort, you can always purchase prescription goggles to use with your helmet.

Comparison Overview 

In the following sections, we’ll go over some common questions and comparisons regarding motorcycle helmet sizes.

Motorcycle Helmet Size vs Hat Size

If you’re a fan of baseball caps, you may be able to use them to help determine your (or a friend or child’s) helmet size. After all, many hat sizes are also based on the circumference of the crown of your head.

However, keep in mind that while the conversion rates between hat sizes and helmet sizes may be similar, they might not be exactly the same.

Large vs Medium Motorcycle Helmets

If you’re stuck between two helmet size choices, it’s best to go with the smaller of the two as long as it doesn’t cause you significant discomfort. You can always adjust the padding inside your helmet or swap it out for smaller pieces, and while you can put more padding in a helmet that’s too large, too, this only works to an extent; eventually, the helmet will be too loose to be safe. 

Youth Large vs Adult Extra Small

One of the more problematic bridges between helmet sizes is the difference between a youth large and an adult extra small. In this case, your best course of action is the same as the above: always choose the smaller size between the two, as long as it doesn’t cause significant discomfort. 

Never, ever buy a helmet to allow your child to “grow into it.” The helmet will not protect your child adequately until they’ve fully “grown into” it, leaving them vulnerable to injury in the case of an accident. 

How to Test the Fit of My Motorcycle Helmet

There are a few things that you should look for when testing the fit of your motorcycle helmet. 

Your Helmet is Too Large If:

  1. You can push it up from the back, and it rotates forward

  2. It shifts from side to side easily 

  3. It rests close to your eyebrows or impedes your vision

Your Helmet is Too Small If It:

  1. Pushes your cheeks up

  2. Causes discomfort, red marks, or pressure points

  3. Sits high on your forehead

If your eyes sit in the center of your helmet’s viewfinder and it fits snugly but comfortably, you have likely found the correct size. 


In the end, finding the correct size motorcycle helmet is always a balancing act. We cannot overstate the value of trying one on in person, as buying one sight-unseen is always a risk, even if you’ve worn or purchased motorcycle helmets before. However, as long as you end up with a helmet that fits you snugly (but not too snugly) and keeps you safe, you’ve succeeded in the end. 

People Also Ask

Do you have any lingering questions that we haven’t answered yet? If so, you may find your answer in the frequently-asked questions below. 

What Size is a Large Motorcycle Helmet?

Believe it or not, a size “Large” is middle-of-the-road as far as helmets go. Helmet sizes can start at XX-Small and go all the way up to 5X Large or more, meaning “Large” isn’t all that large! While measurements can vary between manufacturers, a size “Large” tends to be between 59-60 cm (or about 23.5”).

How to Measure Motorcycle Helmet Size Without Tags

If you’ve found a helmet without the exterior tags and information, you still have one more option; most helmets have an interior label with all of their size information listed on it. However, if that has also been removed, you’ll just have to try it on and see if it fits. A professional may be able to help you estimate or guess the helmet’s size.

Which Motorcycle Helmet Models Fit a Round Oval Head?

If you’re struggling to find a company that produces “Round Oval” sizes, consider checking out companies like Arai, Shoei, or RevZilla. Of course, hundreds of other good manufacturers of Round Oval helmets are out there, so don’t be afraid to research your own, too.

Hi, my name’s Troy. I started riding motorcycles with Clay mid-2020 and soaking up his vast knowledge of bikes. I have been writing for a few years and decided it was a good time to start writing about what I’m passionate about - motorcycles. No matter how bad your day is, a bike will always make you feel better, that’s my motto.