Measure around the forehead, just above the ears, and around the hair in the back to determine head size. If your measurement falls on a size cut off guideline, we recommend that you order the smaller size as there is a bit of stretch in the fleece material. 

SleepPhones® / RunPhones® SizeHat Size (US)Hat Size (UK)InchescmEstimate
Extra Small/SmallUp to 6 3/4Up to 6 3/420 - 21 3/851 - 54Petite women with short hair
Medium (one size fits most)6 7/8 - 7 3/86 7/8 - 7 3/821 1/2 - 23 3/855 - 59Nearly everyone
Extra Large/Large7 1/2 and up7 1/2 and up23 1/2 - 2560 - 63Large and tall men with hair