I Finally Figured Out How to Hang Blinds for Round Windows

I remember standing in a client's attic conversion last July, staring at a gorgeous 36-inch porthole window. The architecture was stunning, but at 6:00 AM, that circle was acting like a magnifying glass, aiming a laser beam of sunlight directly at the homeowner's pillow. We needed blinds for round windows that didn't look like a cheap DIY project gone wrong.

Quick Takeaways for Circular Windows

• Inside mounting is the only way to preserve the architectural curve.
• Cellular sunburst shades are the gold standard for light control and fit.
• Always measure the diameter in at least three places; old houses are rarely perfectly round.
• If privacy isn't an issue, consider 'leaving it naked' to let the trim shine.

The Square Peg, Round Hole Dilemma

The geometry of a circle is a stylist's nightmare when you're used to straight lines and 90-degree angles. I've seen well-meaning homeowners try to slap a straight curtain rod over a porthole, and the result is always the same: it looks like the window has a giant, fabric unibrow. It completely kills the charm of the architecture.

When you have a unique feature like a circular window, the goal isn't just to cover it. It's to dress it so it feels intentional. I once spent three hours trying to hem a curved valance for a client before realizing that fabric alone couldn't fight the physics of a perfect circle. You need structure, usually in the form of a circular blind that can actually hold its shape against the casing.

Do You Actually Need a Blind for Circular Window Shapes?

Before you start drilling, ask yourself if you actually need coverage. If that window is tucked into a hallway or high up in a gable where nobody can see in, I often argue for leaving it bare. A bare porthole with crisp, white-painted trim is a design statement on its own.

However, if it's a bathroom or a bedroom, finding blinds for a round window becomes a functional necessity. You have to balance that 'open' architectural feel with the very real need to not give the neighbors a show. I usually opt for a light-filtering cellular fabric—something around 150 gsm—that glows when the sun hits it without revealing everything happening inside.

Stop Hiding the Trim (And Other Mounting Mistakes)

The biggest mistake I see? The outside mount. People get intimidated by the curve and decide to hang a rectangular shade over the entire opening. It’s a tragedy. It turns a beautiful architectural detail into a generic, lumpy square on your wall.

Forcing standard rectangular roller shades into these spaces makes the room look disjointed and cheap. If you can't see the trim, you've lost the point of having a round window. You want an inside mount that sits flush with the window frame. This requires precision—measuring from the center point out to the edges—but the visual payoff is a treatment that looks like it was built into the house during construction.

Traditional Sunbursts vs. Modern Round Windows Blinds

Most round windows blinds fall into the 'sunburst' category. These are cellular shades that fan out from a central hub at the bottom. In the 80s, these looked like stiff paper fans, but modern versions use much better materials. I’m a fan of 3/8-inch pleats in a soft linen-weave polyester.

If you want something more modern, look for custom-fitted shutters. They are significantly more expensive, but they allow you to tilt the slats for light control. I recently styled a mid-century modern home where we used a matte black wood shutter in a porthole window, and it looked like a piece of custom furniture. It’s about choosing a material that matches the weight of your room’s existing decor.

How to Black Out a Circular Blind in the Bedroom

Achieving total darkness in a circle is the final boss of interior styling. Because the shade has to fan out, there is almost always a tiny pinprick of light at the center hub. It drives some people crazy. I’ve found that using a blackout-lined cellular fabric helps, but you have to be careful with the weight; if the fabric is too heavy, the 'fan' won't close tightly at the bottom.

This is why blackout roller blinds for bedroom windows are so much easier in standard frames—they have tracks. For a circle, you’re relying on a tight tension fit. My trick? Use a small piece of matching adhesive felt inside the center hub to catch those last few light leaks. It’s a tiny hack that makes a massive difference for light sleepers.

My Final Verdict on Dressing Portholes

My rule of thumb is simple: if the window is the star of the room, don't over-accessorize it. Go for a custom-fitted cellular shade that matches your wall color exactly. This makes the blind 'disappear' when it's closed, keeping the focus on the shape of the window itself rather than the texture of the shade.

Don't be afraid of the custom price tag here. A poorly fitted circular shade looks worse than no shade at all. Measure three times, choose a fabric that breathes, and for heaven's sake, keep that beautiful trim visible. Your architecture will thank you.

FAQ

Can I use a regular blind for a round window?

No. A standard rectangular blind will not fit the curve and will leave massive gaps. You need a specific sunburst or arched treatment designed to fan out into a circular shape.

How do I measure for a round blind?

Measure the horizontal diameter across the center and the vertical diameter from top to bottom. If they aren't identical, your window is an oval, and you'll need a template-based custom order.

Do blinds for round windows actually open?

Most sunburst-style blinds are stationary. However, some custom shutters and high-end cellular models can be folded down or tilted, though they are significantly more complex to install.