To measure your head take a tape measure in one hand and your head in the other. Gently wrap the tape measure around your head.
Once you are happy that the measure sits over the widest part of your forehead and reaches all the way round to the back, ask a friend to tell you how big your head is. If there is nobody to do this for you, put a thumb and finger over where the two ends meet and very gently remove the tape from around your head (again with
Caution) and record.
The chart below will give you all possible ramifications from around the world. If you head falls between two measurements then choose the larger sizing for comfort.