We suggest that you check your windows for squareness before you measure for your shade. Using a steel measuring tape, measure the diagonal dimensions as shown here (see picture below). If both measurements are the same, the window is square. If the measurements are different, we recommend that you choose an Outside Mount Shade.
For Inside Mount Shades
Measure the inside width of the window at the top, center, bottom. Write down the smallest measurement. Do not make any deductions. If there is trim or hardware that would interfere with the shade, consider an Outside Mount style (see picture below). Measure the inside length of the window from the top of the frame to the sill. Measure on the left side, the center, the right. Write down the longest measurement. This will be the short point of the shade (see picture below).
For Outside Mount Shades
Measure the width you wish to cover. For the width, have the shade at least as wide as the outside width of the trim around the window, plus 1” each side. You may wish to go a bit wider for more privacy and light control. Measure the width and record this measurement. We recommend mounting the shade at least 2” to 3” above the top of the window trim to allow for the mounting brackets. You may want to go a bit higher to allow for stacking space when the shade is fully raised. Measure the distance from where the top of the shade will be installed to where you want the bottom to rest when the shade is fully closed. Record this measurement. This will be the short point of the shade (see picture below).
