Motorcycle Helmet Size Chart

Getting the right helmet size is the most important decision you'll make when buying a new helmet. A helmet that's too loose won't protect you in a crash; one that's too tight will be distracting and uncomfortable on long rides. Use this guide to measure your head correctly, find your size on the universal chart below, then jump to your brand's specific size chart for a precise fit.

How to Measure Your Head for a Motorcycle Helmet

All you need is a soft tape measure (or a piece of string and a ruler).

  1. Wrap the tape measure horizontally around the widest part of your head — approximately one inch (2.5 cm) above your eyebrows, across your forehead, and around the back at the widest point.
  2. Keep the tape snug but not tight. Take the measurement in centimeters for the most accurate result.
  3. If your measurement falls between two sizes, size down — helmet padding compresses and breaks in over time.
  4. Repeat the measurement twice to confirm.

Universal Motorcycle Helmet Size Chart

Size Head Circumference (cm) Head Circumference (inches)
XS53 – 54 cm20⅞ – 21¼"
S55 – 56 cm21⅝ – 22"
M57 – 58 cm22½ – 22⅞"
L59 – 60 cm23¼ – 23⅝"
XL61 – 62 cm24 – 24⅜"
2XL63 – 64 cm24¾ – 25¼"
3XL65 – 66 cm25⅝ – 26"

Note: Sizing varies between brands and models. Always cross-reference your measurement with your brand's specific chart below before purchasing.

Head Shape Matters Too

Beyond circumference, your head shape affects how a helmet fits. The three most common shapes are:

  • Round Oval — roughly equal in length and width when viewed from above
  • Intermediate Oval — slightly longer front-to-back than side-to-side (the most common shape, and the fit most helmets default to)
  • Long Oval — noticeably longer front-to-back than wide

If a helmet feels like it's squeezing your temples or the front and back, it may be the wrong shape for your head, even if the circumference measurement is correct. Look for the head shape note on each brand's chart below.

Size Charts for 11 Brands

We carry helmets from 11 brands — each with their own sizing. Jump to the chart for your brand:

AGV | Alpinestars | Arai | Bell | Fox | HJC | Icon | LS2 | Scorpion EXO | Shoei | Troy Lee Designs

AGV Helmets

Pista GP RR & K6 S

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

K1 S

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

K3

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

Alpinestars Helmets

Off-Road — Adult

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

Off-Road — Youth

Sizecminches
YSM48–4918⅞–19¼"
YMD50–5119⅝–20⅛"
YLG52–5320½–20⅞"

Supertech R10

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

Arai Helmets

Arai helmets are fit-specific. Each model is designed for a particular head shape — check the note under each model before purchasing.

Contour-X (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Corsair-X (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

XD-5 (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

Regent-X (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Quantum-X (Round Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Signet-X (Long Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

VX-Pro4 (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Classic-V (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Ram-X (Intermediate Oval)

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Bell Helmets

Pit Boss

Sizecminches
XS/S53–5620⅞–22"
M56–5822–22⅞"
L58–6022⅞–23⅝"
XL/2XL62–6324⅜–24¾"
3XL63–6424¾–25¼"

Qualifier, Qualifier DLX MIPS & Qualifier Forced Air

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Lithium

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL64–6625¼–26"

Daytona Helmets

Adult

Sizecminches
3XS43.5–45.717⅛–18"
2XS46–48.318⅛–19"
XS48.6–50.819⅛–20"
S51.5–53.320¼–21"
M53.7–55.921⅛–22"
L56.2–58.422⅛–23"
XL58.7–6123⅛–24"
2XL61.3–63.524⅛–25"
3XL63.8–6625⅛–26"
4XL66.4–68.626⅛–27"

Fox Racing Helmets

Adult & Youth

Sizecminches
YSM (Youth S)49–5119¼–20⅛"
YMD (Youth M)51–5220⅛–20½"
YLG (Youth L)52–5320½–20⅞"
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"

HJC Helmets

Sizecminches
3XS50–5119⅝–20⅛"
2XS51–5220⅛–20½"
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Icon Helmets

Sizecminches
2XS51–5220⅛–20½"
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

LS2 Helmets

Adult

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"
4XL67–6826⅜–26¾"

Scorpion EXO Helmets

Size Chart

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"
4XL67–6826⅜–26¾"

Head Shape Reference

Head ShapeModels
Long Oval EXO-R2000, EXO-GT3000
Intermediate Oval EXO-R1 AIR, EXO-R1 AIR Carbon, EXO-ST1400 Carbon, EXO-T520, Covert FX, Covert 2, EXO-HX1, EXO-R420, EXO-R320, EXO-GT930, EXO-AT960, EXO-AT950, XT9000, VX-16
Round Oval Covert

Shoei Helmets

Sizecminches
XS53–5420⅞–21¼"
S55–5621⅝–22"
M57–5822½–22⅞"
L59–6023¼–23⅝"
XL61–6224–24⅜"
2XL63–6424¾–25¼"
3XL65–6625⅝–26"

Troy Lee Designs Helmets

SE4 / GP Pro

Sizecminches
XS54–5521¼–21⅝"
S55–5621⅝–22"
M57–5822½–22⅞"
L58–5922⅞–23¼"
XL60–6123⅝–24"
2XL62–6324⅜–24¾"

Youth

Sizecminches
YMD50–5119⅝–20⅛"
YLG52–5320½–20⅞"