One Tape Measure, One Minute
Run a soft tape around your head about a centimetre above the ears and across the middle of the forehead – the widest line, not the highest. Keep it snug enough to stay put and loose enough to slide a fingertip under. That number in centimetres is your size, and it is the only measurement any hatter needs from you.
Between Two Sizes, Go Up
Felt and wool relax by three or four millimetres in the first month; straw and stiffened cotton do not relax at all. If you land between sizes, take the larger one and pack it with a sizing tape inside the sweatband. Undoing a hat that is half a size too tight is a job for steam and patience, and it rarely comes back the same shape.
The Fit Test You Can Do in the Mirror
A hat that fits sits level, leaves no red line on the forehead after ten minutes, and stays on when you look down at your shoes. If it lifts when you turn your head quickly, it is too big; if it aches behind the ears, it is too small. Nothing about breaking it in changes either verdict.
