First, get yourself a tape measure made from a flexible material like cloth, fabric, or bendable plastic. If ypu don't have a measuring tape, use string and then measure the string length.
Wrap the tape around your head, making sure you measure above your ears at the area where you prefer to wear your hat. Be sure the tape is above your eyebrows.
Although it is a matter of personal choice, a good spot to measure is the widest part of your head, as that’s where a hat often fits the best. When you get a measurement, consult the charts below to figure out your size.
Measure several times to ensure you’re getting an accurate measurement.
Don’t pull the tape too tight; you always want to err on the side of having a little too much room.
CHECKING YOUR HAT'S FIT
Measure your head and consult our size chart
Your hat should sit above your eyebrows and not obstruct your sight
Allow about a finger of space between your hat and your head
Aim for a snug (not tight) fit