1. Take a measuring tape or, if unavailable, a string to measure later.

2. Place it approximately 1 cm above the ears and eyelashes. Do not tighten too much, as the hat will fit similarly.

3. If the result falls between two sizes, choose the larger size.

4. That's it!

The measurement in centimeters is your hat size in cm.

A conversion chart from other sizing systems is shown above.