There are two ways to finish the edge of a round tablecloth: a ΒΌ" (6 mm) double-fold hem or by adding fabric-covered welting. To determine the yardage for a round tablecloth, divide the tablecloth diameter by the fabric width less 1" (2.5 cm). Count fractions as one width. This is the number of widths you need. Then multiply the number of widths by the diameter and divide by 36" (100 cm) to find the total yards (meters).