Macrame cord comes in different widths. The most common is the 8-millimetre cord (2 ½ strands). If you're looking for something thinner, you can use 12-millimetre cords (3 strands). The finished size should be twice the length of the first cord, then doubled again and folded in half twice. This should give you a finished figure-eight knot that's around 6 inches long and 2 ½ inches wide.