Stop Using Square Blinds for Octagon Window Frames (Try This Instead)

I remember the first time I walked into a late-Victorian remodel and saw a stunning attic nook with a perfect, eight-sided portal to the street. The previous owners, clearly defeated by the geometry, had literally stapled a piece of heavy black felt over it. It broke my heart. We spend so much time hunting for 'character' in our homes, yet the moment we encounter a window that isn't a standard rectangle, we treat it like a problem to be hidden rather than a feature to be celebrated. Finding the right blinds for octagon window frames doesn't have to be a descent into madness, but it does require you to stop thinking in 90-degree angles.

• Inside mounts are non-negotiable if you want to keep the architectural 'wow' factor.
• Custom wood shutters offer the cleanest look and the best light control for angled frames.
• Stationary cellular shades are great for insulation but won't give you a view.
• If you must go outside mount, use motorization to make a square shade feel intentional.

Why Do We Treat Architectural Windows Like Problems?

There is a specific kind of panic that sets in when a homeowner realizes their new bathroom or entryway has a hexagon or octagon window. It usually happens right after you realize a standard 2-inch faux wood blind from the big-box store won't fit. Most people take the path of least resistance: they buy a giant, square roller shade, mount it six inches above the window, and call it a day. Every time that shade is down, your beautiful architectural feature is erased. You might as well have a flat wall.

I have seen gorgeous 1920s bungalows where the octagon window blind was just a tension rod with a saggy piece of lace. It looks accidental. An octagon window cover should feel like a part of the wall's soul. Whether you are looking for octagon window treatments for a cozy reading nook or a window treatment for octagon window placement in a high-ceilinged foyer, the goal is to highlight those crisp 135-degree angles. When you hide the shape, you lose the very thing that makes the room special. I always tell my clients: if the window has eight sides, your window treatment should have eight sides too.

The Cardinal Rule: Never Hide the Angles

The philosophy is simple: if you can see the casing, you should see the shape. This is why I am a fundamentalist about inside mounts for specialty shapes. To do this right, you need to map the exact depth of your window casing. Most octagon window ideas fail because the homeowner didn't realize they only had an inch of depth to work with. You need at least 2 inches of flat surface inside that frame to mount most custom octagon blinds and shades effectively.

Before you even look at fabric swatches, grab a steel tape measure—not a floppy sewing tape—and measure from flat side to flat side, then point to point. If your casing is shallow, you might feel tempted to just slap a curtain for octagon window frames over the whole thing. Resist. Even a shallow frame can often handle a custom-fit shutter or a thin-profile cellular shade. How to cover an octagon window properly starts with respecting the frame. If you hide those angles behind a square curtain, you are essentially apologising for your home’s personality. We don't do that here.

Octagon Plantation Shutters: The Designer's Holy Grail

If you want the absolute best look, an octagon shutter is the gold standard. There is something about the way the louvers can be custom-cut to meet the angled frame that just looks expensive. I usually spec a 2.5-inch louver in a crisp silk white or a stained wood that matches the floor. Because an octagon window shutter is built with a dedicated frame that sits inside your window opening, it covers those awkward gaps perfectly. It looks built-in, not tacked on.

Functionally, shutters for octagon windows are a dream. You can tilt the louvers to let in a sliver of morning sun without exposing the whole room to the neighbors. I once installed a set of octagon window shutters in a primary bathroom where the sun hit the vanity mirror at exactly 8 AM every day. By using a shutter for octagon window frames, the owner could angle the light down toward the floor while keeping the top half of the window clear. It’s a level of light control you just can't get with a fabric octagon window shade. Plus, they don't rattle when the wind blows, which is a major win for older, draftier homes.

The Reality of Cellular Shades for Specialty Shapes

If shutters are out of the budget, a cellular octagon window blind is your next best bet. These are usually designed as a 'sunburst' or fan-style insert. They are incredible for insulation—especially if that attic hexagon window is leaking heat like a sieve—but there is a catch. Most hexagon window shades in a cellular fabric are stationary. They don't move up and down like a standard shade. You pick a position (usually closed or semi-sheer) and they stay there.

This is where people get frustrated. They want the functionality of Day Night Shades where you can swap between sheer and blackout, but specialty geometric windows rarely allow for that kind of dual-action hardware. If you need daily access to the view, cellulars might not be for you. However, for a high-up window where you just want to softened the glare and keep the room cool, a cellular octagon window covering is a sanity-saver. I’ve used them in 300 gsm blackout fabrics for bedrooms where that one little octagon window was letting in a laser beam of light at dawn. Just be prepared for the fact that they are 'set it and forget it' treatments.

What If You Absolutely Have to Outside Mount?

Sometimes the architecture wins. If you have zero depth or the window is an old-school leaded glass style that sits flush with the wall, you have to outside mount. The trick here is to make the square treatment look like a deliberate design choice. I recommend using high-end motorization for these spots, especially if they are in double-height entryways where you'd need a 20-foot ladder just to twitch the cord. A sleek, modern option like Canisteo Motorized Dual Roller Shades Cordless Custom Double Roller Blinds can work beautifully if you mount it wide enough that the entire octagon is revealed when the shade is up.

When you go this route, you aren't just looking for a blind for octagon window coverage; you're looking for a backdrop. Choose a fabric that matches your wall color as closely as possible. When the shade is down, it disappears into the wall. When it’s up, your octagon window takes center stage. This is the only way to do an outside mount without it looking like a cheap DIY octagon window coverings mistake. You want it to feel like a gallery installation, not a cover-up job.

How I Tackle DIY Octagon Window Coverings in a Pinch

If you are on a budget or renting, custom shutters might not be in the cards. In those cases, I love a good 'sunburst' curtain hack. You can find flexible rods or even use small tension rods on the top and bottom flats of the window. Use a sheer linen or a lightweight voile—something around 100 gsm—and cinch it in the middle with a cord or a decorative ring. This creates a 'butterfly' or 'sunburst' octagon window curtain that still honors the shape while providing privacy.

Whether you are doing a DIY project or ordering custom, precision is everything. I once measured a hexagon window for a client and forgot to account for the trim overlap. The shade arrived, and it was a quarter-inch too wide. I had to sand down the inside of her window casing at midnight before her housewarming party. Don't be me. Check out a guide on How To Install Your Shades before you pick up the drill. Take three measurements for every side and use the smallest one. Specialty windows are unforgiving, but when you get the fit right, they are the most rewarding part of a room’s design.

What are the best blinds for octagon shaped windows?

Custom plantation shutters are generally considered the best because they are built to the exact geometry of the frame and offer operable louvers. For energy efficiency, cellular 'fan' shades are a close second.

Can you put curtains on an octagon window?

Yes, but avoid straight rods across the top. Instead, use a sunburst style where the fabric is gathered in the center and attached to the perimeter of the frame, or use individual small rods on each of the eight sides for a truly custom look.

How do you measure for an octagon window shade?

Measure the width and height from the flat edges, then measure the diagonal points. Always measure the depth of the casing to ensure an inside mount is possible. Most custom manufacturers will require a template made of paper for a perfect fit.