To find out your head size for picking the perfect hat, measure your head where you want to wear the hat. If you don't have a measuring tape, use a piece of string or yarn. Wrap it around your head and mark where it meets. Then, lay the string flat and measure it with a ruler or any measuring tape you have.
If you're are in between sizes, opt for a larger option - all Reverie hats contain adjustable inner strap that allows you to reduce the size of the hat by another 2 cm.