Siesta Wool Smoking Hat Cap Fez FES Unisex Men's Women Handmade Fancy Dress Festival

I would like to buy a hat as a gift for my father, whose head perimeter is 62cm. What size hat should I buy?

Circumference . can someone tell. what is the circumference of the 7.3/8? my partner has a big head and i want to get it right!

Id like to buy one for my Dad, his head measures 22 inch / 57cm. What size should I buy?