We recommend meauring your head versus going off of what size you are in other brands. Each brand using their own tools and shapes. To ensure the best possible fit, please reference our chart below. HOW TO MEAURE: Using a cloth measuring tape, measure around your head in centimeters at the point which your hat would sit (approximately one finger above your ear) keep it mind to capture the largest part of the back of your head and not to measure too high up. Measure to the nearest cm, until you get the same size three times to ensure accuracy. You can also use a string or similar, wrap it around then hold it up to a regular tape measure. Pull the tape tightly enough to get an accurate measurement, but do not pull it too tightly. If your measurement is between two hat sizes, it is best to go up. A hat sizing piece can be tucked under the sweatband to cushion a hat and give it a tailored fit. Keep in mind, your hat will break in with wear. Over time, your hat will conform to the unique shape of your head, creating a one-of-a-kind fit.