Finding The Right Fit
Your helmet needs to be the right size for both comfort and efficiency in the event of an accident. It's not rocket science measuring your head but whatever the measurement, you should always try on your helmet before buying.
Everyone's head is different and the type of helmet (longer, rounder, more curved, etc.) will affect how comfy you feel. In some cases, if it's a better fit, it might be best to get a helmet that isn't necessarily the usual style for the kind of activity you’re doing.