Vertical Blind Measurement Guide

For an inside or ceiling mount:
Depending on the size of the window, an inside mount will result in the window glass being partially covered by the stacked blinds when they are opened.

Measure the exact width of the window opening across the top where the head rail is to be installed. Measure from the inside of the trim on the left side to the inside of the trim on the right side. Round the measurement down to the nearest 1/8" and record this measurement. 

Measure the exact height of the window opening from the inside of the trim to the top of the windowsill or to the exact length that you want the blind. Measure the height in three places (the right side, the middle, and the left side of the window). Round the measurements down to the nearest 1/8" and record the shortest (smallest) measurement.

Measure the available depth of your window frame. Be careful not to include inside trim, window cranks or tracks. Measure only the space that is available to install the mounting brackets for the blinds. Record the measurement.

For an outside or wall mount:

Depending on the amount of wall space available, you can have the blinds stack completely off the window glass when they are opened.

Measure the width of the window opening including trim. If there is room, add at least 4" to each side for overlap. This will ensure minimum light gap.

Measure the window opening height. Add at least 3" in height to allow for mounting brackets above the opening and add your desired overlap at the bottom. If your blinds will hang down to the floor or to the windowsill, deduct at least ½" for clearance.