Make sure it stays flat to get an accurate measurement. Note the result in both inches and centimeters, and write it down to take to the store with you.
[header] How to fit a riding helmet [title] Measure your head. [step] Helmet sizes correspond to the circumference of your head measured at its widest point. To find your size, use a flexible measuring tape and wrap it around your head about 1 inch/2.5 cm above your eyebrows.