How to Measure for Window Shades and Blinds?


  • What is the best way to measure yourself inside or outside a building?

Before you measure your windows, you must first decide whether you want the blind to be mounted on the inside or outside of the window frame.

Blinds installed on the inside of the window frame give the room a tidy appearance. On an inside installation, the headrail will be set back from the window casing, emphasizing the window’s real size while allowing your window molding to be seen. If you want your blinds to sit flush with the window molding, make sure your window has adequate depth to allow the headrail’s width (each style of blinds will need a different amount of depth to fit flush, but as a general rule, for blinds that go horizontally across your window, you will need 1 “to 4″ and for vertical blinds, you will need 3″ to 4”. You can still use an inside installation if you don’t have enough depth for a flush mount, since the blind will only protrude slightly from the window molding). 

Blinds installed on the outside of the window frame provide the impression of a longer, broader window and can help conceal an unsightly window. A blind can be placed on the window molding itself or above and beyond the window molding on an outside mount. An exterior mount always gives you more privacy and control over the light. If the window isn’t deep enough to accommodate at least the blind mounting brackets, an outside mount may be your only choice.

Horizontal Blinds Measuring

  • Horizontal Blinds with an Inside Mount

1- Determine the precise width of the window at the top, center, and bottom.
2- Use the narrowest width. Make no assumptions; supply the precise dimensions of the narrowest width. To account for the headrail and mounting brackets, the factory will make the correct adjustments.
3- Measure the exact height of the window on the left, center, and right sides.
4-Make use of the highest height. Make no deductions, provide the exact measurements of the longest height. Vertical blinds will have any required reductions made by the factory to account for the height of the headrail.

 Outside-Mounted Horizontal Blinds

1- Determine the precise width of the place where the blind will be installed.
2- Add for at least 3 inches of overlap to get the best optimum light control and privacy.
3- Take a precise measurement from the top of the planned headrail to the bottom of the sill. If there isn’t a sill, estimate how far the blind will reach.
Add 1 inch to the height for optimum light control.

Vertical Blinds that are mounted on the outside.

  • How to measure for vertical blinds that are mounted on the exterior.

Vertical blinds that are installed on the outside

– Measure the precise width of the window, along with any frames or moldings. To guarantee light control and privacy, add 3 “to each side (6” total overlap).

– Measure the height of the window from the top of the molding to the bottom border, or to the top of the sill if one exists. 3 more “to provide enough mounting space above the window

– If the blind touch the floor (for example, to cover a patio door), measure as in step two but add 1/2 inch “for space so that the vanes do not come into contact with the floor.


Outside mount allowances are not made by the manufacturer.

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