INSIDE INSTALLATION: Width-Measure exact distance between inside surfaces of window at top, middle, and bottom; use the narrowest width. Do not make any width deductions. Length-Measure exact distance from inside surface at top of window to sill. If you prefer blind not to touch sill, deduct 1/4 inch. If there is no sill, measure length to point where blind is to reach.

OUTSIDE INSTALLATION: Width-Measure exact distance between the outermost points where the blind is to be placed. For optimum light control, measurement should extend 3/4" beyond frame on both sides. Factory makes no deduction from your width dimensions. Length-Measure exact distance from where top of blind will be located to top of sill. If there is no sill or if blind is to overlap window frame, measure to point blind is to reach.