Measuring your head size for a custom made to measure or a bespoke hat:
Take a measure around your head circumference, placing it just above your ears, around the back of your head (at widest part) and across your forehead.
Make sure you don’t pull the tape measure too tightly. You are measuring for the fit of your hat, which needs to be comfortable.
It’s useful to place your finger underneath the tape measure to allow a little room. The hat inner head band can always be tightened. It’s easy to do yourself by holding the tape measure to the front.
You can take your measurement in cm or ins.
As a guide the average head size is 22 – 22.5 inches.