Helmet Size Conversion Charts

This helmet size chart has been compiled from helmet manufacturers' literature, sizing charts and years of experience assisting customers with helmet purchases. Not all helmets are created equal. Just because you wear a medium Shoei doesn't mean a medium Arai or Bell will fit.



Measure Your Head

Even if you say you know your size, a good salesperson will still measure your head. Due to different shapes, heads that are apparently the same size when measured with a tape may not necessarily fit the same size helmet.


Measure the circumference (all the way around) of the head at a point approximately one half to one inch above the eyebrows, and at a point on the back of the head that results in the largest possible measurement. Take several measurements, to make sure you have the largest one. Use that one to determine your size.

The standard procedure is measure your head to get your size, put the helmet on & shake your head a little, see how it feels. Have you ever gotten your head stuck in a helmet that was too small? It is not pretty. It is funny for your friends, but you won't like it. It should be snug, but not cutting off the circulation to your scalp or making your eyes bulge.

On the other end of the spectrum when people start way too large, the helmet goes on easily then they shake their head and the helmet goes bouncing down the aisle. When you shake your head the helmet should not move more than 1/4". If the lid shifts on your head just shaking it a little, imagine what it will do on the bike at 65mph. The wind can get under it and it starts to lift or roll back farther on your head.

Regardless of DOT or Snell rating, an ill fitting helmet will not offer the maximum protection in a crash. You can live without a leg or an arm. How many dudes do you know who have no head?

If you want to purchase from an online discount motorcycle helmet retailer, Craigslist or an ebay auction to save money, go for it. Just make sure that before you order it you try on the same, or a similar model from the same manufacturer, first. Never substitute a really great ad and sizing chart for actually trying it on.

Go to a dealer and try on a new helmet. Do not try your buddy'shelmet he bought last year. Helmets wear to the shape of the rider's head. Even after wearing it just a few times, it will be significantly different from a new one.

Even if you are pretty certain of what you want, make sure the retailer has a decent return or exchange policy, in case you change your mind.
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Using the helmet size and conversion charts below you may notice that the inches and centimeter measurements will not be equal nor exact. One centimeter is approximately 0.393700787402 inches. Some manufacturers do not carry the number out 12 decimal places so 21 inches is 53cm to some and 55 to others.

Helmet Size Conversion Chart

Brand HelmetSize Head -Inches Head - cm Hat Size
Answer X-Small
Small
Medium
Large
X-Large
20" - 20 1/2"
21 1/2" - 22"
22 1/2" - 22 3/4"
23 1/4" - 23 1/2"
24" - 24 1/2"
6 5/8" - 6 3/4"
6 7/8" - 7"
7 1/8" - 7 1/4"
7 3/8" - 7 1/2"
7 5/8" - 7 3/4"
Arai XXX-Small
XX-Small
X-Small
Small
Medium
Large
X-Large
XX-Large
XXX-Large
19 1/4" - 19 5/8"
20" - 20 3/8"
20 1/4" - 20 7/8"
21" - 21 5/8"
21 3/4" - 22 3/8"
22 1/2" - 23 1/8"
23 1/4" - 24"
24 1/8" - 24 7/8"
25" - 25 5/8"
49-50cm
51-52cm
53-54cm
55-56cm
57-58cm
59-60cm
61-62cm
63-64cm
65-66cm
n/a
n/a
XS  6 1/2" - 6 5/8"
S  6 3/4" - 6 7/8"
M  7" - 7 1/8"
L  7 1/4" - 7 3/8"
XL  7 1/2" - 7 5/8"
XXL  7 3/4" - 7 7/8"
XXXL  8" - 8 1/8"
Shoei XX-Small
X-Small
Small
Medium
Large
X-Large
XX-Large
XXX-Large
20 1/8" - 20 1/4"
20 7/8" - 21 1/4"
21 5/8" - 22"
22 1/2" - 22 7/8"
23 1/4" - 23 5/8"
24" - 24 3/8"
24 3/4" - 25 1/8"
25 5/8" - 26"
51-52cm
53-54cm
55-56cm
57-58cm
59-60cm
61-62cm
63-64cm
65-66cm
n/a
6 5/8" - 6 3/4"
6 7/8" - 7"
7 1/8" - 7 1/4"
7 3/8" - 7 1/2"
7 5/8" - 7 3/4"
7 7/8" - 8"
8 1/8" - 8 1/4"
Cyber X-Small
Small
Medium
Large
X-Large
XX-Large
XXX-Large
20 1/2"
21" - 21 5/8"
21 3/4" - 22 3/8"
22 1/2" - 23 1/8"
23 1/4" - 24"
24 1/4" - 25"
25 1/4" - 25 5/8"
53cm
55cm
57cm
59cm
61cm
63cm
65cm
XS  6 1/2"
S  6 3/4" - 6 7/8"
M  7" - 7 1/8"
L  7 1/4" - 7 3/8"
XL  7 1/2" - 7 5/8"
XXL  7 3/4" - 7 7/8"
XXXL  8" - 8 1/8"
Fox Racing Youth
KS
KM
KL
Adult
X-Small
Small
Medium
Large
X-Large
XX-Large

18 6/8" - 19 5/8"
19 1/4" - 20"
20 1/8" - 21"

20 1/2" - 21 1/16"
21 1/4" - 22 1/8"
22 3/8" - 23 1/8"
23 1/4" - 23 3/4"
23 7/8" - 24 3/4"
24 7/8" - 25 3/4"



XS

XS
S
M
L
XL
XXL
Suomy X-Small
Small
Medium
Large
X-Large
XX-Large
XXX-Large
20 1/2" - 20 7/8"
21 1/4" - 21 5/8"
22" - 22 1/2"
22 7/8" - 23 1/4"
23 5/8" - 24"
24 1/2" - 24 7/8"
25 1/4" - 25 5/8"
53-54cm
55-56cm
57-58cm
59-60cm
61-62cm
63-64cm
65-66cm
XS  6 1/2" - 6 5/8"
S  6 3/4" - 6 7/8"
M  7" - 7 1/8"
L  7 1/4" - 7 3/8"
XL  7 1/2" - 7 5/8"
XXL  7 3/4" - 7 7/8"
XXXL  8" - 8 1/2"
HJC Youth S/M
Youth L/XL
XXX-Small
XX-Small
X-Small
Small
Medium
Large
X-Large
XX-Large
XXX-Large
19 3/4" - 20 1/8"
20 1/2" - 21 1/4"
19 1/4" - 19 3/4"
20" - 20 1/2"
20 7/8" - 21 1/4"
21 3/8" - 22"
22 1/6" - 22 7/8"
23 1/4" - 23 5/8"
24" - 24 1/2"
24 3/4" - 25 1/4"
25 1/8" - 26"
50-52cm
53-54cm
49-50cm
51-52cm
53-54cm
55-56cm
57-58cm
59-60cm
61-62cm
63-64cm
65-66cm
n/a
XS  6 5/8" - 6 3/4"
n/a
XS  6 3/8" - 6 1/2"
XS/S  6 5/8" - 6 3/4"
S/M  6 7/8" - 7"
M/L  7 1/8"  7 1/4"
L/XL  7 3/8" - 7 1/2"
XL/XXL 75/8" - 7 3/4"
XXL/XXXL 7 7/8" - 8"
XXXL  8 1/8" - 8 1/4"
Thor XX-Small
X-Small
Small
Medium
Large
X-Large
XX-Large
20 1/2"
20 7/8" - 21 1/4"
21 5/8" - 22"
22 3/8"
22 3/4" - 23 1/8"
23 1/2" - 24
24 3/4" - 25 1/8"
52-53cm
53-54cm
55-56cm
57-58cm
59-60cm
61-62cm
63-64cm
XS  6 1/2"
XS/S  6 5/8" - 6 3/4"
S/M  6 7/8" - 7"
M/L  7 1/8"  7 1/4"
L/XL  7 3/8" - 7 1/2"
XL/XXL 75/8" - 7 3/4"
XXXL  7 7/8" - 8 1/8"
Bell Youth Small
Youth Medium
Youth Large
X-Small
Small
Medium
Large
X-Large
XX-Large
19 1/2" - 20"
20" - 20 1/2"
20 1/2" - 21"
20 7/8" - 21 1/4"
21 5/8" - 22"
22 3/8" - 22 3/4"
23 1/4" - 23 5/8"
24" - 24 3/8"
24 3/4" - 25 1/4"
50-51cm
51-52cm
52-53cm
53-54cm
55-56cm
57-58cm
59-60cm
61-62cm
63-64cm
5 7/8" - 6 1/8"
XS  6 1/8" - 6 3/8"
XS  6 3/8" - 6 5/8"
XS/S  6 5/8" - 6 3/4"
S/M  6 7/8" - 7"
M/L  7 1/8" - 7 1/4"
L/XL  7 3/8" - 7 1/2"
XXL 7 5/8" - 7 3/4"
XXL/XXXL7 7/8" - 8"

TheHelmetCenter.com Free Shipping on orders over $100* Sizing Charts for many other brands, including AGV, Icon, THH, Scorpion, and Zox helmets can be found at The Helmet Center website.  Click the banner on the left and then click the yellow Size Guides button, top center.

While the helmet size chart may be the same, street helmet fitment often differs from offroad helmets from the same manufacturer. If you wear an XL street helmet you may only wear a L off-road style. This page will give you a head start and save you from trying on a half dozen helmets before you find your size.

Notes about Arai Helmets


Arai goes to great lengths to create helmets that its customers want. Understanding that not all heads are created equal is what makes some people swear they will never buy another brand. Arai has 3 basic helmet shapes.  

The long oval is designed for heads that are longer front-to-back and narrower side-to-side. Let's be honest.  If you have a giant forehead its hard to find a well fitting helmet. Many other helmet brands can irritate or give you hot, red pressure marks on the upper portion of your forehead.  The long oval is probably best for your riding comfort.

The intermediate oval is suited for those of you with "big heads". You know who you are.  You need a longer front-to-back interior shape and  more interior width, side-to-side.  If you try on a round or long oval and your cheeks push up and practically close your eyes, try an intermediate oval.

The round oval is for riders whose head shapes are more uniform all around.  Most helmet brands use this basic interior shape.


The helmet size cross reference chart below is just to give you a quick idea of where you may fit when switching helmet brands. It is not an absolute rule that if your head measures 7" in circumference only a Bell small will fit you. You may be better off with the Bell medium. The only way to be sure is to try both of the sizes on.

Do not assume that all brands will fit you. For instance my first helmet was a Shoei. I think it was one of the RF models. I never liked it, it never fit "right". The size smaller, I could not get on my head. The size larger was too big. I switched to a KBC and it was better, but not perfect. Then the Shoei Duo-Tec came out. It fits really well, I absolutely love it. Also, I wear glasses and the Duo-Tec flip up design enables me to put on and take off my helmet without removing my glasses.

Everyone has a different head shape. Try on all the brands you can find until you find the one that is right for you.

Helmet to Hat Size Cross-Reference

Hat Sizes -Helmet Sizes
Brand 6 1/4" 6 1/2" 6 5/8" 6 3/4" 6 7/8" 7" 7 1/8" 7 3/8"  7 1/2"  7 5/8"  7 3/4" 8" 8 1/4"
Answer XS XS SM  SM  M L L XL XL
Arai XS XS SM SM M M L XL XL XXL XXXL
Shoei XS XS SM SM M L L XL XL XXL XXXL
Cyber XS S S M M L XL XL XXL XXXL
Suomy XS XS S S M M L XL XL XXL XXXL XXXL
HJC XXS Y-L/XL
XS
Y-L/XL
XS
S S M L L XL XL XXL XXXL
Thor XXS XS XS S S M L L XL XL XXL
Bell YM YL XS XS S S M L L XL XL XXL


Childrens Helmet Size



Buying helmets for children can be time consuming and stressful. When trying a helmet on a child, start with a helmet size that looks too large and show them how to put it on. If you hand to the them and say put this on, they will pull it straight down over their head, bend the ears over and scream. It will hurt to pull it off & they will not want to try again.

To check for proper fitment, tell them to hold still and then you grab the helmet & try to shift it on their head. Just like the adult helmets it should not move more than 1/4".

Most children will complain that it is too tight, even when it fits correctly. Let them wear it for a few minutes. When you remove it check the child's forehead for hot, red marks (not just pink). These are pressure points.

DO NOT buy a helmet that is too large. You do not want them to "grow into it". It will not protect them from head injury until it fits properly.

An ill-fitting helmet can be worse than no helmet at all. If your kid is using one hand to fix her helmet or hold it still, how is she holding on? It can shift while they are riding and block vision. It can also fly off during hard riding.



We have not included any helmet size information for novelty type helmets. They do nothing more than a baseball cap to protect your head in a crash. So it really doesn't matter if they fit well or not.

If you think you look cool in a skid lid, aka brain bucket, just think how cool you will look in your black and chrome wheelchair.

A helmet size chart, no matter how comprehensive it is, is no substitute for trying the helmet on!


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