How to measure Inside mount Window Width: To find the width, measure the top, middle and bottom within your window recess. Use the narrowest width as your window width. Window Length: To find the length, measure exact window-recess length at left, middle and right side. Use the longest height as the window length. Window Depth: Minimum 2 inches required. Ordering: Choose a width that is 1/4 inch smaller than the widow width from above. Choose a length that is same or longer than your window length. Outside mount Determine where the roman shade is to be placed. You will need a minimum 7/8 inches of flat mounting space above your window to accommodate the mounting hardware. Width: Choose a roman blind width that is same or greater than the window width. We recommend add 3-6 inches extra to the measured width to maximize light control and privacy. Length: Measure exact measured-length from the top of the proposed headrail location to the base of sill. If there is no sill, measure where you would like the window roman blind to drop. Add 8-10 inches to the length for optimum light control and privacy. Ordering: Choose a width that is same or wider than the product width from above. Choose a length that is same or longer than your measured length. How to Get a Custom Roman Shade 1. Get the mount type (inside or outside mount) according to your window type 2. Get the roman shade size according to above measurement method 3. Email us the following information 3.1 Product you like (you can send us LINK or ASIN) 3.2 Mount type 3.3 Roman shade size 4. We give you order link 5. Receive the roman shade, if have any problem, please send message to us or call us, we can solve any problem together with you.