We offer three sizes that together will fit almost everybody. XS: Bracelet is approximately 16.5cm in circumference. This size is best for children or those with very small wrists. Regular: Bracelet is approximately 18.5cm in circumference. This is the most common size people buy & typically fits the majority of people. If you aren't able to measure your wrist and are unsure of which size to get, go with Regular. XL: Bracelet is approximately 20.5cm in circumference. This size is for people with very large wrists. MEASURING: To measure your wrist, you can use a string and a ruler or tape measure. 1.) Wrap the string TIGHTLY around the area of your wrist that you would like to wear our bracelet 2.) With your fingernail, pinch the end of the string that completes the circle around your wrist 3.) Measure the string with a ruler or tape measure. We suggest getting the size bracelet that is closest to your wrist measurement in centimeters. If you are having problems with sizing, please contact support and we will do our best to accommodate our inventory.