<Circle Skirt | 2 - Measure around your waist. You don’t want it to be so tight that she can’t breathe. But if the elastic’s too loose on her waist, it will look funny. So measure as precise as you can and add an extra 1 inch for your seam allowance. For Lucy’s skirt, she measures 19 inches around the waist, plus an extra inch = 20 inches of elastic.