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Measure Windows and Doors for New Blinds

New window blinds can give any room a new look, control light coming in and provide privacy. Selecting the best type of blinds and measuring for your installation are easy first steps toward enjoying decorative and functional window blinds in your home.


Selecting Window Blinds for Your Home

There are numerous types of window blinds from which to choose:

  • Horizontal blinds have tilted slats to control sunlight.
  • Vertical blinds are popular installations for sliding glass doors and large windows.
  • Energy-efficient blinds keep cool air in during the summer and cold air out during the winter.
  • Blackout shades block nearly 99% of sunlight from entering a room.
  • Cordless blinds are available for child safety.
  • Some blinds have remote controls to easily adjust for more or less light.

There are two ways to install window blinds:

  • Inside-mounted blinds are installed within the window.
  • Outside-mounted blinds are installed to cover the window frame or attach to the wall.
  • If the window frame is sufficiently deep to attach the mounting brackets inside the window frame, you can choose inside or outside mounting. If not, you’ll have to use an outside mount.
  • Outside mounts require a sturdy wall surface or trim for attachment, which makes it the ideal installation method for standard doors. Inside-mounted vertical blinds won't work on standard doors.
  • The following is a chart of minimum inside-mounting clearances for many popular blinds. Refer to your window blind packaging and instructions for specific measurements or requirements for the blinds you choose.

Minimum Inside-Mounting Clearance (for most brands)

 Cellular Shades 

 Standard and Top-Down / Bottom-Up

5/8 inch
 Cordless / Continuous Cordloop1/2 inch
 Roman Shades 
 Standard and Top-Down / Bottom-Up 5/8 inch
 Cordless / Continuous Cordloop 1/2 inch
 Natural Shades 3/4 inch
 Roller Shades 3 inches
 Metal Blinds 1/2 or 5/8 inch (depending on design)
 Vertical Blinds 2 7/8 inches
 Wood and Faux Wood Blinds 
 1-inch slat 1/2 inch
 2-inch slat 3/4 inch
 2-1/2-inch slat 1 1/4 inches
 Panel Track 
 2 panels 1 1/2 inches
 3 panels 2 1/4 inches
 4 panels 3 inches
 5 panels 3 3/4 inches

 

Lowe's can cut many blinds to custom-fit your windows at no additional cost. Bring in your measurements, and we’ll prepare your blinds while you shop. You can even Special Order just about anything you need for your installation.


Measuring for Inside-Mounted Horizontal Blinds

Measuring for Inside-Mounted Horizontal Blinds

Step 1

Measure the width inside the window frame at the top, middle and bottom to allow for variances in construction.

  • Use the smallest measurement as the window width to make sure that the blinds clear the sides of the window frame.

Step 2

Measure the height inside the window frame at the left, middle and right to allow for variances in construction. (Illustration: Inside-Mount — Measure the Height.)

  • Round the measurements down to the nearest 1/8 of an inch.
  • Use the largest measurement as the window width so the blinds cover the entire opening.
Make a rough sketch of your windows to give to a Lowe’s associate.

Step 3

Take these exact measurements to Lowe's to select your inside-mounted horizontal blinds.

The Lowe’s associate will make any necessary clearance adjustments.


Measuring for Outside-Mounted Horizontal Blinds

Measuring for Outside-Mounted Horizontal Blinds

Step 1

Measure the width to the nearest 1/8 of an inch between the outer-most points where the blinds will be placed.

For optimum light control, the blinds should extend 1 1/2 inches beyond the window opening on each side.

Step 2

Measure the height to the nearest 1/8 of an inch between the highest and lowest points where the blinds will be placed.

For optimum light control, the blinds should extend 1 1/2inches beyond the window opening.

Step 3

Take these measurements to Lowe's to select your outside-mounted horizontal blinds.


Step 4

If you plan to mount your blinds on wallboard, you may need extension brackets.



Measuring for Inside-Mounted Vertical Blinds

Measuring for Inside-Mounted Vertical Blinds

Vertical blinds work best for a window that's wider than its height or for sliding doors.
They can be installed either inside-mounted or outside-mounted. Inside mounted vertical blinds won't work on doors. Use an outside-mount installation.


Step 1

Measure the width inside the window frame at the top, middle and bottom to allow for variances in construction.

  • Use the smallest measurement as the window width so the blinds clear the sides of the window frame.

Step 2

Measure the height inside the window frame from the top of the opening to the sill at the left, middle and right to allow for variances in construction.

  • Use the smallest measurement as the window width so the blinds fit within the opening.

Step 3

Take these measurements to Lowe's to select your inside-mounted vertical blinds.



Measuring for Outside-Mounted Vertical Blinds

Measuring for Outside-Mounted Vertical Blinds

Step 1

Measure the width of the window or door.

  • For maximum light control, add 4 inches to each side.

Step 2

Mark the location where the window blind headrail will be installed.

  • Most manufacturers recommend installation at least 3 inches above the window or door opening.

Step 3

Measure the height from the headrail location to the sill at the left, middle and right sides of the frame.

  • Use the smallest measurement.

Step 4

Take these measurements to Lowe's to select your outside-mounted vertical blinds.