To measure the circumference at its widest, use a tape measure about 2 cm above the brows and around the head. The measurement is your helmet size in centimeters—for example, if your head circumference is 56 cm, your helmet size is M/57. The Schuberth helment is available in many sizes, depending on the model. To find out which size fits you best, just take your head circumference and compare it to the list of recommended sizes. If you want to buy a larger size, we recommend going up one size; if you want to buy a smaller size, go down one size. Here are some examples: If your head circumference is 58 cm, you should choose a size M/59. If your head circumference is 52 cm, you should choose a size L/53. If your head circumference is 64 cm, you should choose a size H/65. It's important to remember that these are only guidelines. You should always try on several helmets before making your choice. Also note that most sizes will fit more than one model of helmet, so don't feel limited by what they offer. Helmets are measured differently across brands. Some companies include the width of the face shield in their sizing calculations while others do not.