Use a soft measuring tape
Place the tape around your head about 1 inch above your eyebrows
Keep the tape level around the widest part of your head
Wrap it around the back of your head where it is fullest
Make sure the tape is snug but not tight
Read the measurement in inches or centimeters
Measure twice to confirm accuracy
Compare the measurement to the helmet size chart
Choose the helmet size that matches your measurement
If between sizes, try both for the best fit