Measure circumference of your head...just above top of ears and just above the eyebrows. Wrap a soft measuring tape gently around your head, making certain that the tape lies midway on your occipital bone (that little bump in the middle of the back of your head). Don't pull the tape too tightly or your hat will fit that tightly. Measure 2 or 3 times to be accurate. You now have your correct head size, so that I can design a custom hat to fit you properly...