Measuring normal square windows? No sweat. But the ones in my attic have this weird arch at the top, and I wasn’t sure how to even start. I ended up using a flexible tape measure (like the kind for sewing) to trace the curve, then measured the widest and tallest points with a regular metal tape. For the arch, I sort of eyeballed the midpoint and measured from base to peak. For triangles, I did all three sides and the height just in case.
I drew a rough sketch with all my numbers and gave that to the blinds company, but I still felt like I was guessing a bit. Anyone got a more foolproof way to do this? Or maybe a trick for those windows with really wavy edges? I’d love to hear if someone has a hack that doesn’t involve fancy tools or math I forgot from high school.
For the arch, I sort of eyeballed the midpoint and measured from base to peak.
Eyeballing works in a pinch, but I’ve seen a lot of folks end up with blinds that just don’t fit right—especially on those oddball arches. What I usually tell people is to cut a big piece of cardboard that fits snug into the window, then trace the curve exactly. Pull it out, measure your max width and height on the cardboard, and send that as a template. It’s low-tech, but way more accurate than guessing curves. Wavy edges are trickier… sometimes it’s just easier to call the window folks for a custom fit if you want it perfect.
Pull it out, measure your max width and height on the cardboard, and send that as a template.
That cardboard tracing trick is a lifesaver, especially if you’ve got an arch that isn’t a perfect half-circle. I’ve done the “eyeball and hope” method myself, and it’s hit or miss. Like you said, “wavy edges are trickier…”—I tried to fit blinds on a gothic arch once and ended up with a gap big enough for a squirrel to squeeze through. Templates just take the guesswork out. Still, if you’re just after basic coverage and not too picky, eyeballing can get you close enough—depends on how precise you need it.
Templates just take the guesswork out. Still, if you’re just after basic coverage and not too picky, eyeballing can get you close enough—depends on how precise you need it.
Totally get where you're coming from. I tried the “good enough” route on a weird triangle window in my attic and, yeah, it worked... sort of. The light still sneaks around the edges though. If you want it to look halfway decent, that cardboard trick is worth the extra 10 minutes. But for spots nobody sees much? Eyeballing isn’t the end of the world.
That cardboard template trick really does save a headache, especially for those oddball shapes. I once tried to make a paper template for a window with a half-circle top—looked ridiculous, but at least the shade fit better than my first attempt. I totally relate about the light sneaking in; it’s wild how even a tiny gap feels like a spotlight at night. For super wavy edges, I’ve actually taped butcher paper over the window and traced right on it, then cut it out and used that as my guide. Not fancy, but it worked better than my math skills ever could.
That’s a clever workaround with the butcher paper—never would’ve thought of that for wavy edges. I’m always torn between trying to measure every angle or just tracing the shape directly. Do you find the traced template holds up if you need to redo it later, or does it get stretched out? I’ve had cardboard warp on humid days and mess up my fit, so I’m always wondering if there’s a “perfect” material for templates, or if it’s just trial and error every time.
I’ve had cardboard warp on humid days and mess up my fit, so I’m always wondering if there’s a “perfect” material for templates, or if it’s just trial and error every time.
Cardboard’s definitely not my favorite for that exact reason—humidity turns it into a potato chip. I’ve had better luck with thin MDF or even those cheap plastic sheet protectors taped together. They don’t stretch or warp much, and you can reuse them. Nothing’s perfect, but at least they don’t melt in the rain...
Nothing’s perfect, but at least they don’t melt in the rain...
I tried using those plastic sheet protectors once—worked better than cardboard for sure, but I found they slid around a bit while tracing. Maybe I just taped them wrong? MDF sounds solid, but isn’t it kind of a pain to cut for weird shapes? I keep wondering if there’s a cheap material that holds up but doesn’t take forever to work with.
Funny enough, I’ve run into the same sliding issue with those plastic sheets—taping only helps so much, especially if you’re working overhead or on a wall. MDF’s great for stability but yeah, it’s a pain for tight curves unless you’ve got the right saws. Ever tried using foam board? It’s cheap, holds its shape, and you can cut it with a box cutter. Curious if anyone’s found something even sturdier that doesn’t cost a fortune or require a workshop full of tools...
Ever tried using foam board? It’s cheap, holds its shape, and you can cut it with a box cutter. Curious if anyone’s found something even sturdier that doesn’t cost a fortune or require a workshop full of tools...
I’ve definitely gone down the foam board route for those weird window shapes—especially the arched ones in our 1940s place. It’s way easier to handle solo compared to MDF, and you’re right, just a box cutter does the trick. Only thing I’ve noticed is sometimes the thinner stuff warps if you lean on it too much while tracing, but doubling up seems to help.
For something sturdier, I once tried using that corrugated plastic (the stuff realtors use for yard signs). It’s surprisingly tough and still pretty easy to cut with a utility knife. Doesn’t flex as much as foam board and doesn’t crumble at the edges either. Downside is it’s a bit slippery when you’re marking out curves—chalk tends to wipe off unless you’re careful.
One trick I picked up from an old neighbor: he used thin hardboard (like 1/8" masonite). Not as cheap as foam but not crazy expensive either. You can score it with a sharp blade and snap it for straight cuts, though curves are still tricky unless you have patience. For tight arches, he’d rough out the shape with several little straight cuts and then sand down the curve. Takes more time but works if you want something reusable.
Honestly, I still end up using whatever’s left over in the garage half the time—cardboard from appliance boxes has saved me more than once. Not fancy but gets the job done when all you need is a quick template.
Funny how every window seems to need its own approach... never thought making templates would be such an art form.