Use a soft measuring tape
Wrap the tape around your head about 1/8 inch above your eyebrows and ears
Keep the tape level all the way around your head
Make sure the tape is snug but not tight
Read the measurement where the tape meets
Measure in inches or centimeters
Measure twice for accuracy
Use the largest measurement if you get different results
Compare the measurement to a hat size chart
Choose the hat size that matches your measurement