Know your hat size... If you do not know your head size, meaure the head with a tape measure and take measurements in centimetres or inches. Pull tape snug but not tight. An average head size is 58 cms in European Sizing or 7 1/8 UK sizing and 7 1/4 US sizing. | Hat Sizes | | Head Size | Hat Size (Number) | Hat Size (Letter) | | 21-5/8” | 6-7/8 | XXS (55cm) | | 22" | 7 | XS (56cm) | | 22-3/8" | 7-1/8 | S (57cm) | | 22-3/4" | 7-1/4 | M (58cm) | | 23-1/8" | 7-3/8 | L (59cm) | | 23-5/8" | 7-1/2 | XL (60cm) | | 24" | 7-5/8 | XXL (61cm) | |