Curtains and drapery panels come in standard lengths of 63 inches, 84 inches, 95 inches, 108 inches and 120 inches. Tier curtains, also referred to as café curtains or kitchen tiers, come in 24-inch and 36-inch lengths. Panel widths vary according to style and manufacturer, but 54 inches is a standard width.
Window treatment measurements are given in width and length, with the width mentioned first. The length is measured from the top of the rod pocket to the bottom edge of the panel. When hung, the panel normally just reaches the floor or windowsill. To determine the number of panels needed for a window, the width of the window is multiplied by 1.5, 2, 2.5 or 3, depending upon the amount of fullness desired.