Hat Size Converter
Convert hat sizes between head circumference in centimetres, US and UK fitted sizes such as 7⅛, and letter sizes, or measure your head to find your size.
Advertisement
About this tool
European hat sizes are simply your head circumference in centimetres. US fitted sizes, such as 7⅛, are that circumference in inches divided by pi and rounded to the nearest eighth, and UK sizes run an eighth smaller than US for the same head. Letter sizes vary most between makers.
Measure where the hat will sit, just above your eyebrows and ears. If you fall between sizes, choose the larger: a slightly loose hat can be tightened with sizing tape, but a tight one can’t be stretched much.