How To Size A Motorcycle Helmet

Learn how to find the correct helmet size for your head.

Wearing a motorcycle helmet is at least as crucial as buckling up your seatbelt when you drive in a car. Both are important precautions that maximize safety in case of an accident, but just wearing a motorcycle helmet doesn't ensure your safety. You have to wear a helmet that is the correct size and shape for your head.

Regardless of whether or not wearing a helmet is a requirement in your state, statics and common sense support always wearing one when riding a motorcycle. The National Safety Council found the "NHTSA [National Highway Traffic Safety Administration] estimates that, since 2002, more than 25,000 lives have been saved by wearing motorcycle helmets. This includes 1,872 lives saved in 2017. If all motorcyclists had worn helmets, an additional 802 lives could have been saved in 2017."

Over the course of 16 years, 25,567 lives were saved by wearing motorcycle helmets according to research collected by the National Highway Traffic Safety Administration and National Safety Council.
Over the course of 16 years, 25,567 lives were saved by wearing motorcycle helmets according to research collected by the National Highway Traffic Safety Administration and National Safety Council.National Safety Council

A helmet with proper fit is safer and more comfortable. We will go through the key steps to help you correctly determine your motorcycle helmet size, head shape, and fit, so you can purchase the appropriate helmet.

Protect your head with a properly sized motorcycle helmet to decrease the chance of injury in case of an accident.
Protect your head with a properly sized motorcycle helmet to decrease the chance of injury in case of an accident.Jeff Allen

How To Measure For A Motorcycle Helmet

We invited Shoei Helmets North America’s marketing coordinator to our office to demonstrate how to measure for optimal helmet size. The information provided here will give you a solid foundation on how to seek best fit on your own, then you can visit a motorcycle helmet dealer, get measured there, and try on different sizes. Better dealers are trained to help you best determine a comfortable, secure fit.

We brought in Shoei’s marketing coordinator to demonstrate the correct way to measure for helmet size. Begin by wrapping a flexible measuring tape around the largest perimeter of your head, about 1 inch above your eyebrows.
We brought in Shoei’s marketing coordinator to demonstrate the correct way to measure for helmet size. Begin by wrapping a flexible measuring tape around the largest perimeter of your head, about 1 inch above your eyebrows.Jeff Allen

Start by wrapping a flexible measuring tape horizontally around your head, approximately 1 inch above your eyebrows, write down the measurement, refer to the brand's size chart, and select the best corresponding size. If you are in between sizes, try the smaller size first, as suggested in the MC Garage video.

Take note of the measurement (it doesn’t hurt to note the figure in centimeters, as well as inches).
Take note of the measurement (it doesn’t hurt to note the figure in centimeters, as well as inches).Jeff Allen

Sizes can run in XS, S, M, L, XL, XXL and XXXL, and sometimes even larger. Units of measurement can be in inches and/or centimeters, depending on helmet manufacturer.

Refer to the appropriate size chart in order to get the most accurate helmet size. Shoei’s size chart includes centimeters and inches.
Refer to the appropriate size chart in order to get the most accurate helmet size. Shoei’s size chart includes centimeters and inches.Shoei

To fit the wide variety of face and head shapes in this world, padding options can help tailor the helmet accurately to your dimensions. Helmet manufacturers often provide easily changeable cheek pads (and other changeable interior pads) of different thicknesses for this purpose. Shoei, for example, provides 31-, 35-, and 39-millimeter-thick cheek pads.

How To Size A Motorcycle Helmet For Your Head Shape

Companies such as Arai also categorize helmets based on various head shapes such as Round Oval, Intermediate Oval, and Long Oval. Arai's managing director informed me there is really no science to determining head shape and that it comes down to how the helmet fits your head. Your best option is to visit a dealer to try on a variety of helmets offering different head shapes to find which fits best.

Determining your head shape may lead you to find that you can fit into a smaller helmet than your measured size. In further explanation from Arai, “Depending on where your head measures within a range, your measured size might be snug or loose, depending on shape. So a medium Quantum-X (Round Oval) might be loose, but a small Signet-X (Long Oval) might offer just enough room to fit snugly. This of course depends on the width of your head. So measured size is always just part of the process, while test fitting will give you the final answer.”

How Tight Should A Motorcycle Helmet Be?

Begin by putting on the helmet. To put on a helmet, pull the straps out and pull the helmet on by inserting your head, sliding the back of your head along the back of the helmet, rotating the chin of the helmet down as the helmet is fully donned. Do not pull the helmet straight down onto your head because although the shell has a few millimeters of give when you pull the straps out, a properly fitting helmet will be snug. Attempting to pull straight down causes you to pull down onto the widest part of your head with your temples, cheekbones, and ears in the way.

After the helmet is on, note if there are any uncomfortable pressure points. Discomfort/pressure while the helmet is on or red spots on exposed skin after removing the helmet are indicators that you should try a different size or helmet shape. For example, I experience some pressure on the top of my forehead and redness appears when I wear a size small with some helmet brands, but after getting sized by Shoei’s marketing coordinator, he recommended that I shift to a medium based on my dimensions.

When you push the helmet up from the back it should not rotate forward. If it does, the helmet is too big.
When you push the helmet up from the back it should not rotate forward. If it does, the helmet is too big.Jeff Allen

When further checking the fit, the helmet should be tight enough that it should not rotate forward if pushed up from the back and snug enough that it should not easily shift side to side when pushing the helmet horizontally.

The helmet should not shift when pushed from side to side.
The helmet should not shift when pushed from side to side.Jeff Allen

A key tip that Shoei’s marketing coordinator provided was that the helmet should fit so that your eyes are centered in the viewport. If the helmet rests on or is close to your eyebrows, it is too large. If it is high on your forehead and your cheeks are pressed up, then it is too small.

The XS (top) was difficult to put on, pushed my cheeks up, and was tight around my forehead. The S was, again, just a little too tight around the forehead, and the M (bottom), as the Goldilocks’ mantra goes, fit just right.
The XS (top) was difficult to put on, pushed my cheeks up, and was tight around my forehead. The S was, again, just a little too tight around the forehead, and the M (bottom), as the Goldilocks’ mantra goes, fit just right. My eyes are in the center of the viewport and there wasn’t any discomfort around my forehead.Jeff Allen

Further, this video provided by Shoei is a helpful resource that details sizing and offers more tips on determining how tight the helmet should be, such as fitting the brow line correctly to where two fingers cannot fit between your head and the liner.

How Much Is A Motorcycle Helmet?

A motorcycle helmet, like motorcycles themselves, vary in price and style. There are half, open-face, full-face, and modular (the chin bar flips up) helmets available. Since half helmets and open-face/three-quarter helmets leave significant areas exposed, full-face or modular helmets are recommended for maximum protection.

Based on Dr. Dietmar Otte’s accident research diagrams, this image reflects the combined percentages of the left and right sides of the helmet’s impact zones. Further, it shows the highest impact zone is the chin at 34.6 percent.
Based on Dr. Dietmar Otte’s accident research diagrams, this image reflects the combined percentages of the left and right sides of the helmet’s impact zones. Further, it shows the highest impact zone is the chin at 34.6 percent.Robert Martin

What can you expect to pay for a full-face helmet? Well-known brands and price ranges for their respective full-face helmets are listed here: Shoei ($399.00–$731.99), Arai ($689.95–$3,995.95), HJC ($94.99–$204.99), Bell ($109.95–$749.95), Schuberth ($479.00–$899.00), Shark ($259.95–$759.95), and 6D ($599.95–$745.00).

How much does a modular helmet cost? Shoei ($699.00), HJC ($154.99–$219.99), Bell ($244.97), Schuberth ($579.00–$799.00), and Shark ($289.99–$469.99).

What are the price ranges for open-face helmets? Shoei ($328.99–$499.00), Arai ($469.95–$679.95), HJC ($69.99–$174.99), Bell ($119.95–$339.96), and Shark ($249.99–$399.99).

Half helmets? HJC ($59.99–$114.99) and Bell ($104.97–$174.97).

In general, helmets are unisex in design and structure making them appropriate for male or female riders.

There are also helmet options for children. While some kids may fit adult XS helmets depending on their head size and shape, companies such as HJC offer the CL-Y Solid, a child-specific motorcycle helmet that is available in youth small (49–50cm), youth medium (51–52cm), and youth large (53–54cm).

Variations in pricing within the company’s offerings are typically a result of different grades of lining material, graphics, and structure.

For example, the entry-level full-face helmet from Shoei, the RF-SR retails for $399, is both DOT and Snell 2020D certified, and is less than the RF-1200 ($485) because it offers different features. Shoei’s marketing coordinator explained that “the interior [of the RF-SR] is more standard versus the RF-1200 which has performance materials to help absorb and dissipate sweat faster than the traditional stuff. Graphics will also add to the costs as does the more sophisticated EPS (expanded polystyrene) design, not for safety but for ventilation channels throughout them. Safety-wise they have the same standards and very similar density EPS liners. They both will use the same shield system as well and exact same shield, so their viewports are identical.”

Going to the top of Shoei’s full-face helmet lineup is the higher-spec flagship, the X-Fourteen, which retails for $731.99. It is higher in price because of “all the different features it has inside and out. One, the shell design is more complex as are the spoilers all over it. More sophisticated EPS design offers more ventilation throughout the chin-bar EPS and main EPS liner. Also, the interior has different materials and is more customizable than ever. Each section of the center pad can be removed and replaced with optional thicknesses of pads to help fine-tune the fit for racers. However there are some similarities to the RF-SR and RF-1200 that include the same base-plate system (so shields can be shared between all these models) shell and EPS materials, and safety standards (Snell 2020D & DOT).”

At different ends of the full-face price spectrum include the DOT-certified HJC CS-R3 Solid for as low as $94.99, and Arai’s Corsair-X RC which is priced at $3,995.95.

The Corsair-X RC is expensive for a few reasons. Its carbon fiber shell is based on Arai’s Formula 1 racing helmet’s GP-6RC technology. Further, the carbon used is—according to Arai’s managing director—at “the top of the food chain, with a price to match.” Support materials, too, are at the high end of the price chart. Another factor is labor: A shell expert takes a full day to focus and build by hand one shell’s layup. “The complexity of the layers and positioning of all the support materials requires that much attention,” the managing director continued. For comparison, the shell expert can produce more than 100 of the standard fiberglass configuration of the Corsair-X.

Knockoff helmets can be found on eBay or Amazon at terrifyingly low prices (like a half helmet for $27—it makes my head hurt just thinking about it), but these are cheap for various reasons (lack of quality parts, lack of sufficient testing/research, etc.) and should not be considered if safety is the aim. A quality helmet is a worthwhile investment, particularly from brands that have researched and tested extensively for years with MotoGP racers, impact-simulation machinery, and crash tests in order to meet safety standards.

What Are DOT And ECE? Motorcycle Helmet Safety Standards

DOT certification (safety standard issued by US Department of Transportation) and Snell certification (safety standard issued by independent/private Snell Memorial Foundation) are two of the most common that you find on many current helmets in the US, however, there are also ECE (European safety standard), JIS (Japanese safety standard), as well as others intended to meet other countries’ requirements.

MIPS is also another safety development which is described in detail here. In short, MIPS (Multi-directional Impact Protection System) consists of a low-friction layer between liners that allows 10–15mm of sliding action of the rider's head independent of the direction of impact, which may reduce chance of injury.

Regardless of whether you are purchasing a men's or women's motorcycle helmet, it is important to take a few extra steps to ensure a proper fit by measuring correctly, being mindful of helmet shapes offered, identifying pressure points, and adjusting helmet size or padding accordingly, to find the helmet that gives you the best protection and suits your budget. Also, remember to take care of your helmet by keeping the inner pads and outside shell clean of oils and debris.