Measuring vertical blinds for a sliding glass door involves more than measuring the glass. You also need to consider the door trim or molding, where the headrail will actually be mounted, how much space the vertical blind will occupy when it is fully open, and whether door handles, walls, cabinets or other obstructions will interfere with the treatment.
Most common vertical blinds installed over sliding glass doors are outside mounted. That means you are generally specifying the overall size of the blind rather than the size of a recessed opening. For an outside-mount vertical blind, the ordered height includes the complete blind from the top of the headrail to the bottom of the vanes.
At Blinds Chalet, we recommend deciding exactly where you want the finished blind to begin and end before taking your final measurements. Think of your measurements as defining the outside boundaries of the complete vertical blind: the top measurement represents where the top of the headrail will sit, while the left and right measurements determine the overall coverage across the door.
This guide walks you through the process step by step and explains the details that can make the difference between a vertical blind that simply covers the door and one that fits and operates the way you expected. Learn more about the best blind options for sliding patio doors.
Learn more: How to Measure for Window Blinds
How Do You Measure Vertical Blinds for a Sliding Glass Door?
For most sliding doors, first determine whether you want the vertical blind to cover only the glass, cover the surrounding trim, or extend far enough beyond the door for the vanes to stack completely off the glass when open.
Measure the full width you want the finished blind to cover and the height from where you want the top of the headrail to sit to where you want the bottom of the vanes to end. Because sliding-door vertical blinds are usually outside mounted, the dimensions you provide generally represent the overall ordered width and height.
A common starting point is to extend the blind approximately 2 to 3 inches beyond the opening on each side and provide approximately 2 to 3 inches of mounting area above the opening when space allows. If the vertical blind needs to stack completely off the glass, additional width will usually be required on the stacking side.
| Measurement | What to Consider | Why It Matters |
|---|---|---|
| Overall Width | Glass, trim, overlap and desired stacking space | Determines how much of the door is covered and whether the vanes can stack off the glass |
| Overall Height | Top of headrail to desired bottom of vanes | Outside-mount height includes the headrail |
| Side Overlap | Often approximately 2 to 3 inches per side when space allows | Improves coverage and provides mounting room |
| Top Mounting Space | Allow room for headrail and brackets above the door | Prevents the headrail from interfering with trim or molding |
| Stack Width | Space occupied by the vanes when fully open | Determines whether the open blind covers part of the glass |
| Obstructions | Handles, walls, cabinets, trim and furniture | Can limit the width, stack direction or mounting position |
Vertical Blinds Over Sliding Doors Are Usually Outside Mounted
Most vertical blinds covering sliding glass doors are installed as outside mounts. The headrail is attached above the door opening to the wall, trim or molding rather than recessed inside the door frame.
This gives you flexibility to extend the treatment above and beyond the opening for better coverage and to create additional stacking space.
Why Outside Mount Works Well for Sliding Doors
- Provides more room for the vertical blind headrail and mounting brackets.
- Allows the treatment to extend beyond the glass for improved privacy and light control.
- Provides additional space for the vanes to stack when the blind is open.
- Can help clear door handles and other hardware.
- Allows you to mount above decorative trim or molding.
When ordering an outside-mount vertical blind, remember that the dimensions you provide are used to determine the overall size of the treatment. Do not measure only the glass unless you actually want the finished blind to be approximately that size.
How to Measure Around Door Trim or Molding
Sliding glass doors commonly have trim or molding surrounding the opening. Before measuring, decide whether your vertical blind will mount directly on the trim, above the trim or on the wall beyond it.
Measuring From the Outside of the Trim
One practical method is to measure from the outside edge of the trim on one side of the door to the outside edge of the trim on the other side. This gives you a natural starting point for the width because the vertical blind will cover the entire trimmed opening.
You can then add additional width beyond the trim if you want greater privacy, more light coverage or additional room for the vertical vanes to stack.
Mounting Above the Trim
We often recommend mounting the headrail above the door trim when there is sufficient wall space. This keeps the mounting brackets from interfering with decorative molding and gives the headrail a solid mounting area.
If you mount above the trim, include the height of the trim when determining your overall vertical blind height. Then add enough additional height above the molding to accommodate the headrail and mounting brackets.
The goal is not simply to add an arbitrary number of inches. Determine where you want the top of the headrail to sit and measure from that point down to where you want the vertical vanes to end.
Step 1: Determine the Overall Width of the Vertical Blind
Start by determining the left and right boundaries of the finished vertical blind. Rather than thinking only about the dimensions of the glass, decide where you physically want the blind to begin and end on the wall.
If there is trim around the sliding door, measure the full outside width of the trim as your starting point.
Add Side Overlap
When space allows, adding approximately 2 to 3 inches beyond the opening or trim on each side is a useful starting point. This gives the vanes additional coverage along the edges and provides more room for the headrail.
More overlap may be appropriate in some installations, particularly if you want the vertical blind to stack farther off the glass. However, additional width should always be checked against walls, cabinets, switches and other nearby objects.
Step 2: Decide Where You Want the Vertical Blinds to Stack
One of the most overlooked measurements for a sliding-door vertical blind is the stack width. When vertical blinds are opened, the vanes collect together at one side or at both sides depending on the selected draw configuration.
That group of vanes still takes up space. If the headrail is only slightly wider than the sliding glass door, the stacked vanes will cover part of the glass even when the blind is completely open.
Stacking Over the Glass
If you do not mind the stacked vanes covering part of the glass, you can keep the overall blind width closer to the width of the door opening. This can be useful when wall space is limited.
Stacking Completely Off the Glass
If you want the entire sliding door opening exposed when the vertical blind is fully open, you need to provide enough additional width for the vane stack to sit beyond the edge of the glass.
Determine the approximate stack width for the particular vertical blind you are ordering and extend the headrail far enough beyond the door opening on the stacking side to accommodate it.
The required stack width varies based on the overall blind width, vane size, product construction and draw configuration, so check the specifications for the specific vertical blind before finalizing your order.
Which Direction Should Vertical Blinds Stack?
The best stack direction usually depends on which side of the sliding glass door is used for entry and how the room is arranged.
| Stack Style | How It Opens | Good Choice When |
|---|---|---|
| Left Stack | Vanes collect on the left side | The active door and room layout make the left side the better parking area |
| Right Stack | Vanes collect on the right side | The right side provides better clearance for the open blind |
| Split Stack | Vanes divide and stack on both sides | You want a centered opening or do not have enough stack space on one side |
Before choosing the stack direction, open the sliding door and think about how people actually move through it. You generally do not want the stacked vanes positioned where they interfere with the active doorway.
Step 3: Determine the Overall Height
For an outside-mount vertical blind, measure from the point where you want the top of the headrail to sit down to the point where you want the bottom of the vanes to end.
This distinction is important because the ordered height of an outside-mount vertical blind includes the complete treatment, including the headrail. The height is not simply the length of the vertical vanes.
Mounting Above Door Trim
If the sliding door has trim or molding, locate the top edge of that molding. Then determine how far above it you need to position the headrail so the brackets can mount securely and the headrail clears the trim.
Depending on the installation, approximately 2 to 3 inches of additional mounting area above the opening may work well, but the actual amount should be based on the headrail and bracket dimensions of the product you are ordering.
Where Should the Vanes Stop?
For a floor-length installation, measure down to the point where you want the vanes to stop above the floor. Allow enough clearance so the vanes do not drag across carpet, tile, wood flooring or a door threshold.
If the vertical blind will stop above another surface rather than the floor, measure to the desired stopping point instead.
Remember That the Headrail Is Included in the Height
This is one of the easiest mistakes to make when ordering outside-mount vertical blinds.
If you order a vertical blind at a specified height, that measurement represents the overall height of the finished treatment from the top of the headrail to the bottom of the vanes.
For example, if you want the top of the headrail at 84 inches above the floor and you want the bottom of the vertical blind to end 1/2 inch above the floor, your measurement needs to represent that complete top-to-bottom distance.
Do not measure only from the bottom of the headrail or from the top of the vanes unless the measuring instructions for your specific product explicitly tell you to do so.
Step 4: Check for Door Handles and Other Obstructions
Once you know your proposed width and height, check everything around the sliding door that could interfere with the vertical blind.
Sliding Door Handles
Door handles can project into the path of the vanes. Check how far the handle extends from the glass or door frame and make sure the vertical blind will have sufficient clearance to move and rotate freely.
Nearby Walls
A sliding door located close to a perpendicular wall may not have enough room to extend the headrail several inches beyond the opening. This can limit the amount of off-glass stacking available.
Cabinets and Built-Ins
Kitchen cabinets, bookcases, entertainment centers and other built-ins can restrict how far the vertical blind can extend to one side.
Light Switches and Outlets
Check for switches, outlets, thermostats and other wall-mounted items before extending the blind beyond the door trim.
Baseboards and Floor Trim
Wide baseboards or projecting trim may also affect how the bottom of the vanes hangs against the wall.
Measure Where You Want the Blind to Actually Sit
One of the easiest ways to avoid confusion is to stop thinking of the measurement as the size of the sliding glass door and instead think of it as the size of the finished vertical blind.
Stand in front of the door and determine exactly where you want the treatment to begin and end.
- Top: Where do you want the top of the headrail?
- Left: Where do you want the left end of the headrail?
- Right: Where do you want the right end of the headrail?
- Bottom: Where do you want the bottom of the vanes?
Those boundaries provide the overall outside-mount dimensions you are trying to determine.
This approach also makes it easier to account for trim, stacking space and obstructions because you are designing the placement of the complete treatment rather than simply copying the dimensions of the glass.
Example: Measuring a Sliding Door With Trim
Suppose the outside edges of the trim around a sliding glass door measure 72 inches wide and 80 inches high.
You decide you want approximately 3 inches of additional coverage on each side. You also want to mount the headrail 3 inches above the top of the trim and allow approximately 1/2 inch of clearance above the floor.
| Item | Example |
|---|---|
| Outside Trim Width | 72 inches |
| Left Overlap | 3 inches |
| Right Overlap | 3 inches |
| Initial Overall Width | 78 inches |
| Additional Stack Space | Add more if needed to stack completely off the glass |
| Top of Headrail | 3 inches above top trim |
| Bottom of Vanes | Approximately 1/2 inch above the floor |
The final width may need to be greater than 78 inches if you want the vertical vanes to stack completely beyond the glass. That amount should be based on the stack width of the particular vertical blind you are ordering.
Standard Coverage vs. Full Off-Glass Stack
| Feature | Standard Coverage | Full Off-Glass Stack |
|---|---|---|
| Overall Width | Closer to the width of the opening plus normal overlap | Wider to accommodate the vane stack |
| Glass When Fully Open | Partially covered by stacked vanes | Can be nearly or completely exposed |
| Wall Space Needed | Less | More |
| View Through Door | Stack remains visible over part of opening | Maximum open view |
| Best For | Rooms with limited wall space | Large views and frequently used patio doors |
Common Mistakes When Measuring Vertical Blinds for Sliding Doors
Measuring Only the Glass
The size of the glass is useful information, but it may not be the correct order size. Outside-mounted vertical blinds often need to extend beyond the glass and surrounding trim.
Forgetting About the Vane Stack
A vertical blind that is exactly the width of the opening will still cover part of the glass when it is fully open. If an unobstructed opening is important, provide additional width for the stack.
Ignoring Door Trim
Trim affects both the width and mounting height. Decide whether you are mounting on the trim or above it before taking final measurements.
Measuring Height as Vane Length Only
For an outside-mount vertical blind, the ordered height includes the headrail. Measure from the desired top of the complete headrail to the desired bottom of the vanes.
Not Leaving Enough Room Above the Door
The mounting brackets and headrail need sufficient space. Do not position the top measurement so close to decorative molding that the hardware cannot be mounted correctly.
Adding Width Without Checking the Wall
Additional width is useful for overlap and stacking, but a wall, cabinet or other obstruction may prevent the headrail from extending as far as you planned.
Forgetting the Door Handle
Make sure the vanes have sufficient clearance from handles and locks so they can rotate and traverse without constantly hitting the hardware.
Sliding Door Vertical Blind Measuring Checklist
- Decide where the headrail will mount: On the trim, above the trim or on the surrounding wall.
- Measure the outside width of the trim or opening: Use this as your starting width.
- Add side overlap: Approximately 2 to 3 inches per side is a common starting point when space allows.
- Decide where the vanes will stack: Left, right or split.
- Determine whether you want the stack on or off the glass: Add sufficient width if you want the opening fully exposed.
- Check the available wall space: Make sure the proposed headrail width fits without hitting walls or cabinets.
- Determine the top of the headrail: This is the starting point for your height measurement.
- Allow room for brackets: Mount sufficiently above molding or trim for the hardware you are using.
- Measure to the desired bottom position: Allow appropriate floor or sill clearance.
- Remember that height includes the headrail: Do not measure vane length alone.
- Check door-handle clearance: Make sure the vanes can traverse and rotate freely.
- Measure twice: Confirm the final overall width and height before placing your order.
Not Sure What Size to Order? We Can Help
Sliding doors are one of the places where a few extra minutes of planning can make a significant difference in the finished installation. If you are unsure how much width to add for stacking, where to position the headrail or how to work around trim and door handles, you do not have to guess.
Start by measuring the sliding door opening and surrounding trim. Then note how much wall space is available on the left, right and above the opening, where the active sliding door is located and whether anything nearby could interfere with the blind.
Our window treatment team can help you work through the layout and determine where the finished vertical blind should sit before you place the order.
How To Measure Other Applications
- How to Measure For French Door Blinds or Traditional Door Blinds
- How to Measure Blinds or Shades for Corner Windows
- How to Measure Blinds or Shades for Tile or Moulding
- How to Measure Window Coverings for Bay Windows
- How to Measure for RV Windshield Shades
Expert Guidance from Blinds Chalet
Blinds Chalet has helped homeowners measure and order custom window treatments since 2006. When we help customers measure vertical blinds for sliding glass doors, we do not focus only on the size of the glass. We look at the complete installation: the trim, headrail position, stack direction, available wall space, door handles and how the customer wants the doorway to look when the blind is fully open.
One of the most important decisions is whether you are comfortable having the vertical vanes stack over part of the glass or whether you want them to move completely off the opening. If you want the door fully exposed, the headrail usually needs to extend farther beyond the opening to provide room for the stack.
We also recommend deciding exactly where you want the finished blind to sit before measuring. For an outside mount, your top measurement represents the top of the headrail, and the overall height includes both the headrail and the vanes. Your left and right measurements determine the complete width of the blind.
Product dimensions, stack widths, mounting brackets and factory specifications vary between vertical blinds, so always review the measuring requirements for the exact product before placing your order. If you are uncertain, contact us before ordering and we can help you work through the measurements.
Vertical Blind Measuring FAQs
How do I measure vertical blinds for a sliding glass door?
For an outside mount, determine where you want the complete vertical blind to begin and end. Measure the overall width from the desired left edge to the desired right edge and measure the height from the desired top of the headrail to the desired bottom of the vanes. Account for trim, side overlap, stacking space and nearby obstructions before finalizing the measurements.
How much wider should vertical blinds be than a sliding glass door?
Adding approximately 2 to 3 inches of overlap on each side is a common starting point when space allows. More width may be needed on the stacking side if you want the vertical vanes to move completely off the glass when the blind is open.
How high above a sliding door should vertical blinds be mounted?
The headrail needs enough space above the opening or trim for its mounting brackets and hardware. Approximately 2 to 3 inches above the opening or trim may work for many installations, but the exact mounting height should be based on the headrail and bracket requirements of the specific vertical blind.
Should I measure the glass or the trim for vertical blinds?
For an outside-mounted vertical blind, measuring the outside edges of the door trim is often a useful starting point because the blind will usually cover the complete trimmed opening. You can then add additional width for overlap or stacking space as needed.
What is vertical blind stack width?
Stack width is the amount of horizontal space occupied by the vertical vanes when the blind is completely open. If you want the vanes to stack completely off the glass, the headrail must extend far enough beyond the door opening to accommodate that stack.
Can vertical blinds stack completely off a sliding glass door?
Yes, when sufficient wall space is available. The vertical blind can be ordered wider than the door opening so the stacked vanes sit beyond the glass. The amount of additional width required depends on the stack width of the specific vertical blind.
Does the ordered height of an outside-mount vertical blind include the headrail?
Yes. For an outside-mount vertical blind, the ordered height represents the overall treatment height from the top of the headrail to the bottom of the vanes. It is not simply the vane length.
Should vertical blinds stack on the left or right side of a sliding door?
The best stack side depends on which panel of the sliding door is active, the location of nearby walls and furniture, and where you have sufficient space for the stacked vanes. Choose a configuration that keeps the primary doorway as clear as possible.
Do I need to account for a sliding door handle when measuring vertical blinds?
Yes. Check how far the door handle projects and make sure the vertical vanes have enough clearance to traverse and rotate without hitting it. Handles, locks and other hardware should be evaluated before choosing the mounting position.
What if there is a wall or cabinet next to my sliding glass door?
A nearby wall, cabinet or built-in can limit how far the vertical blind headrail can extend beyond the door. Measure the available wall space before adding overlap or extra width for off-glass stacking and consider changing the stack direction if the opposite side provides more room.
Can Blinds Chalet help me measure vertical blinds for a sliding door?
Yes. Measure the door opening and trim, note the available wall space above and on both sides, identify which door panel opens and record any handles or other obstructions. Blinds Chalet's window treatment team can help you work through the layout and ordering measurements before you place your order.
