Ring Sizer, Find your US ring size, Sizing Tool
Not sure what your ring size is? This ring size tool works like a belt. Simply push the end through the buckle to form a ring shape. Slip the sizing tool on to your finger and adjust to a comfortable fit. Make sure you can still slide it over your knuckle. When the best fit is achieved, read off the size indicated by the arrow. (Size pictured is a 7)