M. A. Baskind Company: Measuring for Blinds

How to Measure for Blinds and Shades

For all measurements:

The window covering will hang inside the window frame and cover the window glass exactly.

Width: Measure the EXACT distance across the window from the inside edge of the frame to the opposite inside edge in three places. Use the NARROWEST dimension.
Height: Measure the EXACT distance from the top inside edge of the frame to the bottom inside edge (or the sill) of the frame in two places. Use the SHORTEST dimension. If you prefer that the shade not touch the sill, deduct ¼".
Make no other deductions or additions!! The factory will make all necessary deductions for operating clearance.
Window depth: The amount of space from the back of the window or obstruction to the window's outer edge. Different styles will require different clearance -- call for more information on your specific style.

The window covering will hang outside the actual window glass, generally covering the window frame.

Width: Measure the EXACT distance from the outside edge of the left side of the window frame to the outside edge of the right side of the window frame. For proper light control, add at least 1 ½" (¾" on each side) to your measurement. Check the individual blind specification for recommendations on overlap.
Height: Measure the EXACT distance from the top outside edge of the window frame to the sill OR from the top outside edge of the window frame to the bottom outside edge of the frame. If you measure to the sill and prefer that the shade not touch the sill, deduct ¼". Check individual the blind specification for recommendations on additional overlap to add.