XJRider.com

I decided to start shopping for a decent helmet for the kids, as all they have right now is an open-face motocross helmet. Of course, sizing is difficult anyway, even harder in kids sizes, and downright confusing from one brand to the next. So, I did some extra work and simplified the process a bit by making a cross-reference chart of the listed sizes for each of the major brands. I figured if it helped me, it might help you, too. It's a pretty large image, so right-click and open it in a new tab and/or download it if it's hard to read here.

Notes:

• - Inch/Centimeter measurements are the circumference of the head about 1 inch above the eyebrows.
  - Actual youth sizes are indicated with a "Y" preceding the size, i.e.: "Y M" = "Youth Medium". A size that does not have the "Y" ("XS", for example) in the youth section indicates the adult equivalent size where there was no actual youth size listed.
  - As with any apparel, these sizes are a guide only. Helmets are made differently, so try before you buy.