For a full, generous semi-sheer look, plan for total panel width equal to 1.5 to 2 times your window opening. A 180 cm window needs 270–360 cm of total fabric — that's 2 panels at 140 cm each (280 cm) for a practical fit, or 3 panels for a fuller, more gathered look. For very wide windows, bay windows, or floor-to-ceiling glass, contact the ZIPCushions team with your exact dimensions and they can advise on the best panel configuration.