Measure your head
Determine the circumference of the widest part of your head by using a flexible tape measure. Generally, the widest part of a person's head is the area 2.5cm (1") above the eyes and ears. However, we suggest measuring at a few points both above and below that line to determine the greatest measurement before referring to our size tables. We also suggest testing the fit of a helmet one size smaller and one size larger then what the chart recommends. No helmet can provide protection if it's too uncomfortable to wear.