Use a tape measure to determine the lenght. Wrap the tape gently, not too tight around your head just above top of ears, completely circling your head.
Basically all you need is to measure your head exactly where you want your hat to sit. If you fall between sizes, choose the next largest size. Please measure 2-3 times to be acurate.

If you have any furter questions or wish for extra sized hat please contact us  for support.