Purchasing a hat on the internet can be difficult if you are not sure if the hat you see will fit your head properly. Did you know that an adult hat can fit a young child? Well.........if you follow these simple direction below, perhaps it will help you determine if the hat you want to purchase will fit when you get it home. So, here is how to measure your hat size: 1.) Measure around your head about 3/4 of a inch above your ear where your hat will be worn. 2.) A cloth tape measure such as a seamstress or tailor uses is ideal. (If you do not have one of these, simply use a piece of string, measure and put the string next to a yard stick. 3.) It is usually helpful to have someone help you. 4.) Pull the tape tight to measure within 1/8". 5.) Now measure from the top center of your head to your eyebrow or where you would like the edge of the hat to rest on your forehead. This is the depth of the hat. 6.) Read off the numbers and use the chart below to determine your hat size. INFANT / TODDLER DIAMETER: SMALL: 19 INCHES MEDIUM: 19 ½ INCHES LARGE: 20 INCHES DEPTH: 6 to 6½ INCHES YOUNG CHILD / ADULT DIAMETER: SMALL: 21 ½ INCHES MEDIUM: 22¼ INCHES LARGE: 23 INCHES X-LARGE: 23 3/4 INCHES DEPTH: YOUNG CHILD: 7 INCHES DEPTH: ADULT: 7 ½ INCHES.