How to measure your head and size a motorcycle helmet: size charts for Shoei, AGV, HJC, Arai and Schuberth

Measure your head once, check the maker's chart, then try the helmet on: the chart only gets you to the right shelf. SHARP, the UK government's helmet-rating scheme, cites a European study in which 12% of helmets were lost during the impact, and notes that even a five-star helmet will not protect you if it is not on your head. The same label does not mean the same head size across brands: an HJC L covers 58 to 59 cm while an AGV or Shoei L covers 59 to 60 cm. This guide gives the measuring method, the charts side by side, the conflicting advice on what to do between two sizes, and which sizes Canadian stores had in stock on 2026-10-21.

How to measure your head

Size charts by brand

Schuberth names its C5 sizes by head circumference: shell 1 covers XXS (51) to L (59) and shell 2 covers XL (61) to XXXL (65). HJC's chart has a step that AGV's and Shoei's do not: S 55 to 56 and M 57 to 58 match, but HJC L is 58 to 59, XL 60 to 61 and 2XL 62 to 63. A 60 cm head is a Shoei, AGV or Arai L and an HJC XL; a 59 cm head sits in the L of all four. Our AGV vs HJC guide shows the overlap model by model. Measure, then check the chart for each helmet, because makers' charts differ by model.

Between two sizes: the advice conflicts

Shoei's fitment page says that if the head measurement falls between two sizes you should try the smaller helmet first, and HJC's fit page says to try the larger first and then the smaller (Shoei fitment guide, HJC proper fit). Neither is wrong; both are starting points before you check how the helmet sits. Try both sizes, in the same helmet. Arai approaches it differently: its 2017 parts book lists optional interior liners in 5, 7, 10 and 12 mm for each size, so a fit can be adjusted without changing shell size. The next question after size is head shape, which our head shape guide covers.

The fit check

• Fasten the strap tight enough that you can still open and close your mouth (SHARP).
• Feel for the helmet against your whole head with no pressure points or red marks, and keep it on for a few minutes (SHARP).
• Rotate it side to side: in a full-face your cheeks should follow the helmet and stay in firm contact with the cheek pads; if it moves or slips it is probably the wrong size (SHARP).
• Tilt it forward and back; again it should not slip (SHARP).
• Shoei: the top pad should press on the top of your head and the cheek pads on your cheeks, so your teeth drag along the inside of the cheeks as you open and close your mouth.
• SHARP's roll-off test: with the strap done up and your head tipped forward, ask someone to push up from the rear base of the helmet. If it rolls off in the shop, it will come off in a crash.

Which sizes are in stock in Canada

Two things stand out. The RPHA 12 is thin in S and M (3 and 4 of 7 stores), so a small-head rider may find the cheapest listing is not in their size, while the RF-1400 was also listed in 3XL at 6 of 10 stores. And the lowest price on a model page can be one size: the K6 S CA$364 lowest is a 2XL clearance colourway, and the usual CA$799.99 applies to the plain colour in every size. See our K6 S vs RPHA 12 comparison and the compare page. Check the retailer's return terms for helmets before ordering a size you have not tried; we did not verify store policies.

Stock counts are a dated snapshot (ALLR data, 2026-10-21). For how a helmet ages once you own it, see the lifespan and maintenance guide, and for comparing the brands in detail the AGV vs Shoei guide.