For windows measuring You will need Up to 29in wide 2 Panels 30in - 39in 2 Panels 40in - 48in 2-3 Panels 49in - 72in 3-4 Panels 73in - 96in 4-5 Panels 97in - 120in 5-6 Panels 121in - 144in 6-7 Panels