From the Jump Bucket Fabric Hat

What you need to determine your head circumference

- Measuring tape, folding rule or ruler
- If necessary, a string or a piece of thread (if no measuring tape is at hand)

The easiest and fastest way to determine your head circumference is with a measuring tape. Simply wrap the measuring tape around your head, placing it over the widest part of the back of your head and meeting it at the center of your forehead. Make sure the measuring tape is not too tight, otherwise the cap will feel too snug. You have now determined your cap size: the number of centimeters you read on the measuring tape corresponds to your head circumference.

Don't have a measuring tape handy?

No problem! In this case, simply take a string (or a piece of thread) and wrap it around your head just as we described above for measuring with a tape measure. You can now measure the length of the string you wrapped around your head using a folding rule or a ruler to read off your head circumference in centimeters.