A properly fitted toe ring will be large enough to slide over the widest part of your foot but small enough to sit where you’d like it—usually at the narrowest point of the toe. While adjustable toe rings have a gap to let them cinch down or open enough to accommodate a toe of almost any size, your fitted toe ring may be such a tight fit that you’ll need to lubricate your toe with lotion to get the ring on and off.
Wrap a piece of string around your toe. Make sure the string wraps around your toe at the point where you’d like the ring to rest.
Mark where the end of the string overlaps itself, forming a complete circle.
Stretch the string out against a ruler to measure the distance between the end and the marked overlap point, in millimeters. Round down to the nearest millimeter.
Convert your toe circumference in millimeters to a ring size. If necessary, use a ring sizing chart (see Resources). Some retailers may accept your ring size in millimeters circumference, so you may not need to do a conversion.