Inside Mount shades get mounted or positioned inside the window frame or casement. In order to do this, there must be at least 1" of flat mounting depth inside the window as our standard shades are made on headrails that have a depth of 3/4". This mounting depth ensures that the shade can lay flush with the opening of the window and. Inside mount shades are great for a seamless, modern look. However, inside mount shades require us to take a width deduction to ensure the shade will properly fit inside the window casement. We keep this deduction minimal at 1/4" off the narrowest width measurement we receive, but it does mean that the shade cannot possibly cover the entire window opening fully. Thus, if total blackout is required, inside mount shades may not be the best way to go. Outside mount shades get mounted outside the window on the window frame itself, the drywall above the window or, in the case of French doors, the door frame above the glass. Unlike with inside mount shades, we do not take a a width deduction off of the measurements we receive for outside mount shades, rather we make the shade to the widest measurement we receive, so as to cover the most area. Outside mount shades are recommended for rooms where blackout is of utmost importance. In these instances, we recommend adding width to the shade to cover any light gaps on the sides of the window. Outside mount shades are also recommended for windows without depth or for French doors.