Not sure which size Sena smart motorcycle helmet you need? Measure around the widest part of your head, approximately 2.5 cm above your eyebrows, then compare your measurement with the relevant Sena helmet size chart below. Most Sena helmets use a familiar sizing system, but some models have different measurements.
Our Sena helmet size guide covers the Outlander adventure helmet, Phantom ANC, Phantom family, Specter, Stryker, Outrush, Outstar and older Momentum ranges. Find your helmet below and check the appropriate size chart before ordering.
Sena Smart Motorcycle Helmet Size Charts
Important: Sena helmet sizing can vary between models. Always identify your helmet before choosing a size, even if you've previously owned another Sena helmet. All measurements below are in centimetres and refer to head circumference.
Sena Outlander Adventure Helmet Size Chart
The Sena Outlander is a dual-sport adventure motorcycle helmet with integrated Mesh communication equipment. It combines adventure helmet styling with built-in intercom technology, removing the need to fit a separate communication system.
The Outlander uses Sena's standard sizing measurements:
| Helmet Size |
Head Circumference |
| S |
55–56 cm |
| M |
57–58 cm |
| L |
59–60 cm |
| XL |
61–62 cm |
| XXL / 2XL |
63–64 cm |
Although the Outlander follows Sena's standard measurements, its adventure helmet design and internal padding can affect how it feels when worn. Make sure the helmet fits securely around your head and cheeks without uncomfortable pressure.
See the Sena Outlander adventure helmet at RaceLeathers, or browse our complete Sena range.
Manufacturer reference: Sena Outlander size chart.
Sena Phantom ANC Helmet Size Chart
The Sena Phantom ANC is a full-face smart motorcycle helmet featuring integrated communication equipment and Active Noise Cancellation (ANC).
The Phantom ANC uses the same published head measurements as the standard Sena Phantom family:
| Helmet Size |
Head Circumference |
| S |
55–56 cm |
| M |
57–58 cm |
| L |
59–60 cm |
| XL |
61–62 cm |
| XXL / 2XL |
63–64 cm |
Although the Phantom ANC shares the same published sizing measurements as other Phantom models, the internal components and padding can affect how the helmet feels.
Check that the helmet sits securely without excessive movement or uncomfortable pressure around your head and ears. Its built-in communication system doesn't change the importance of getting the helmet fit right.
See the Sena Phantom ANC motorcycle helmet at RaceLeathers.
Manufacturer reference: Sena Phantom family.
Other Sena Smart Motorcycle Helmet Sizes
The following Sena smart helmets share the standard head circumference measurements used by the Outlander and Phantom ANC:
- Sena Phantom
- Sena Phantom XB
- Sena Phantom Unplugged
- Sena Specter
- Sena Impulse
- Sena Outrush 2
- Sena Outrush R
- Sena Outride
- Sena Outstar 2
| Helmet Size |
Head Circumference |
| S |
55–56 cm |
| M |
57–58 cm |
| L |
59–60 cm |
| XL |
61–62 cm |
| XXL / 2XL |
63–64 cm |
These models share the same published head measurements, but their internal shapes and padding may differ. Not every model is manufactured in every size shown.
Sena Stryker Helmet Size Chart
The Sena Stryker uses different measurements from many other Sena smart helmets, particularly from Large upwards.
| Helmet Size |
Head Circumference |
| S |
55–56 cm |
| M |
57–58 cm |
| L |
58–59 cm |
| XL |
60–61 cm |
| XXL / 2XL |
62–63 cm |
For example, a 60 cm head circumference corresponds to Large on the standard Sena chart, but XL on the Stryker chart.
Always use the Stryker-specific chart when choosing a Sena Stryker helmet.
Manufacturer reference: Sena Stryker size chart.
Sena Outstar and Outstar S Helmet Size Chart
The original Sena Outstar and Outstar S open-face helmets use a different sizing convention from the newer Outstar 2.
| Helmet Size |
Head Circumference |
| S |
57–58 cm |
| M |
59–60 cm |
| L |
61–62 cm |
| XL |
63–64 cm |
Important: The Outstar 2 uses the standard Sena measurements shown earlier. Don't use the original Outstar chart when choosing an Outstar 2.
Manufacturer reference: Sena Outstar sizing.
Sena Momentum Series Helmet Size Chart
The older Sena Momentum smart helmet range includes an XS size and uses the following head measurements.
| Helmet Size |
Head Circumference |
| XS |
53–54 cm |
| S |
55–56 cm |
| M |
57–58 cm |
| L |
59–60 cm |
| XL |
61–62 cm |
| XXL / 2XL |
63–64 cm |
This chart is included for riders researching older Sena helmets. Always check the manufacturer's guidance for your exact Momentum model.
Manufacturer reference: Sena Momentum sizing.
Why Do Sena Smart Helmet Sizes Differ Between Models?
Although many Sena motorcycle helmets use the same measurements, different models can have different internal shapes, padding arrangements and shell constructions.
For example, Large on the Sena Outlander corresponds to 59–60 cm, while Large on the Stryker corresponds to 58–59 cm. The original Outstar uses a different sizing convention again.
It's worth checking the correct chart even if you've owned a Sena helmet before. The same letter size doesn't always mean the same fit.
How to Measure Your Head for a Sena Helmet
You'll need a flexible tape measure, preferably the type used for sewing. If you don't have one, use a piece of string and measure it against a ruler afterwards.
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Position the tape: Wrap it around the widest part of your head, approximately 2.5 cm above your eyebrows and just above your ears.
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Keep it level: Make sure the tape sits flat against your head without being pulled excessively tight.
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Measure your head: Record the circumference in centimetres.
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Check again: Repeat the measurement two or three times to confirm accuracy.
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Find your helmet model: Identify the correct Sena size chart above.
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Choose your starting size: Compare your measurement with the chart, then try the helmet on to confirm the fit.
If possible, ask someone to help you measure. It's easy to position the tape incorrectly when doing it yourself.
How Should a Sena Smart Motorcycle Helmet Fit?
A correctly fitted Sena smart helmet should feel snug and secure without causing painful pressure points. The helmet should move with your head rather than sliding around independently.
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Forehead and temples: The internal lining should make firm, even contact without causing pain.
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Cheeks: On helmets with cheek pads, these should feel snug against your face.
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Crown: There shouldn't be noticeable gaps between your head and the internal lining.
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Movement: With the chin strap correctly fastened, gently move the helmet from side to side and up and down. It should remain secure.
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Comfort: Wear the helmet indoors for a while to check whether uncomfortable pressure develops.
Remember that a smart helmet must fit properly as a motorcycle helmet first. Built-in Bluetooth, Mesh Intercom and ANC technology don't change the importance of correct sizing.
Does Built-In Communication Equipment Affect Helmet Fit?
Sena smart helmets contain integrated communication components, including speakers, microphones and internal electronics.
The helmet should still fit securely without uncomfortable pressure around your ears, cheeks or temples.
For helmets such as the Phantom ANC, make sure the internal speaker and ear areas feel comfortable when the helmet is correctly positioned.
Never modify the protective shell or EPS liner to make communication equipment fit. Follow Sena's instructions for any permitted comfort adjustments.
What If You're Between Two Sena Helmet Sizes?
If your head circumference falls between two sizes, try both where possible.
Different Sena models can have slightly different measurements, so check the relevant chart rather than automatically choosing your usual helmet size.
A correctly fitted helmet should feel snug without painful pressure points or excessive movement.
The comfort padding may settle slightly over time, but the protective EPS liner isn't designed to compress to accommodate an incorrectly sized helmet.
How Do You Know If a Sena Helmet Is Too Big?
A Sena helmet may be too large if it moves independently of your head, feels loose around the cheeks or slides onto your head with very little resistance.
With the chin strap correctly fastened, gently move the helmet forwards, backwards and from side to side. Excessive movement may indicate that the size or internal shape isn't suitable.
Remember that the comfort padding can settle further with use, so a helmet that's already loose when new isn't a good starting point.
How Do You Know If a Sena Helmet Is Too Small?
A helmet that's too small may cause painful pressure around your forehead, temples or the sides of your head.
Some initial firmness is normal, particularly around the cheek pads, but persistent discomfort isn't something you should simply put up with.
For more advice, read our guide to dealing with a tight motorcycle helmet.
Can You Wear Glasses With a Sena Smart Helmet?
Many riders wear spectacles with their Sena helmets, although comfort depends on the particular model, your glasses and your head shape.
Try the helmet with your usual glasses whenever possible. Check that the arms don't create uncomfortable pressure around your temples or interfere with the helmet's internal speaker areas.
Our guide to wearing glasses with a motorcycle helmet
Try Sena Motorcycle Helmets at RaceLeathers
A helmet size chart is a useful starting point, but there's no substitute for trying a motorcycle helmet on properly.
At RaceLeathers in Darwen, Lancashire, we can help you check motorcycle helmet fit and find a suitable size and shape.
Visit RaceLeathers at 136 Bolton Road, Darwen, Lancashire, BB3 1BZ. We're open Monday to Saturday, 10am to 5pm.
Get directions to RaceLeathers on Google Maps.
Browse our complete Sena range of motorcycle helmets, communication systems and accessories, or explore our full selection of motorcycle helmets.
Sena Smart Helmet Sizing FAQs
Are Sena smart motorcycle helmets true to size?
Most Sena smart motorcycle helmets use the manufacturer's standard size chart, but some models have different measurements. Always use the chart for your particular helmet.
What size Sena Outlander helmet do I need for a 58 cm head?
A 58 cm head circumference corresponds to Medium in Sena's Outlander sizing chart. Always try the helmet on to confirm the fit.
What size Sena Outlander helmet do I need for a 60 cm head?
A 60 cm head circumference corresponds to Large in Sena's Outlander sizing chart.
What size Sena Phantom ANC helmet do I need for a 58 cm head?
A 58 cm head circumference corresponds to Medium in the Sena Phantom ANC sizing chart.
Are the Sena Outlander and Phantom ANC size charts the same?
Yes. Both use the same published head circumference measurements, from Small at 55–56 cm to XXL at 63–64 cm. However, their different helmet designs and internal padding may affect the final fit.
Does the Sena Phantom ANC fit differently because of its electronics?
The Phantom ANC shares its published sizing measurements with other Phantom models, although its internal components and padding can affect how it feels. Check for uncomfortable pressure around the ears and make sure the helmet fits securely.
Does Sena make XS motorcycle helmets?
Some older Sena models, including the Momentum series, include XS at 53–54 cm. Many newer Sena smart helmets start at Small, covering 55–56 cm.
Are Sena Stryker helmets sized differently?
Yes. The Stryker uses different measurements from Large upwards. Its Large covers 58–59 cm, XL covers 60–61 cm and XXL covers 62–63 cm.
Are the Sena Outstar and Outstar 2 sizes the same?
No. The original Outstar uses different measurements from the newer Outstar 2. Always use the correct model-specific chart.
Do Sena helmet liners loosen over time?
The internal comfort padding may compress slightly with regular use, but the protective EPS liner shouldn't be expected to change shape to accommodate your head.
What if my Sena helmet model isn't listed?
Check Sena's model-specific size chart or helmet manual before choosing a size. Don't assume every Sena smart helmet uses the same measurements.
Where can I get Sena helmet fitting advice in Lancashire?
Visit RaceLeathers at 136 Bolton Road, Darwen, Lancashire, BB3 1BZ. We're open Monday to Saturday, 10am to 5pm. Get directions on Google Maps.
