Measuring the head to determine the correct helmet size:

Measuring the head is the starting point for determining your correct helmet size. Use a cloth measuring tape.

Determining your correct helmet size begins with measuring the circumference of your head. This measurement should be taken at a point approximately one inch above the eyebrows in the front and at the point on the back of the head that results in the largest possible measurement. Several measurements should be taken to be sure that the largest one has been obtained.