Measure your head, then use the hat sizing chart below. To measure your head, take a flexible tape measure and wrap it around yourhead above your ears and eyebrows where your hat would normally sit. If your head size falls between two sizes, we recommend that youchoose the larger size of the two. If you don't have a soft tape measure, you can cut a piece of paper to wrap around your head and thenmeasure the paper with a ruler. Take this measurement twice to get an accurate measurement. Small pieces of foam (resizing pads) can easilybe inserted behind the sweatband if the fit is a little loose. Different hat manufacturers’ size standards may vary slightly. In the event of a hat not fitting, we will happily swap for another size.