Finding a ski helmet that fits is a bit like Goldilocks: not too tight, not too loose, but just right.
A ski helmet should fit snugly, with no spaces between the foam or padding and your head. If a helmet can rock back and forth, or moves around when you shake your head from side to side, it’s too big. Try a size down, or if the helmet has an adjustment mechanism, try tightening it. If a helmet causes headaches, it’s too tight. Go a size up, or, loosen it up.
Following a brand’s size chart is a good place to start. If this is your first time buying a helmet, or you don’t already know your size for a particular brand, we recommend trying on helmets in person to get a feel for what you like. Or at least, check an online retailer’s return policy.