{"id":608,"date":"2026-10-21T19:49:32","date_gmt":"2026-10-21T11:49:32","guid":{"rendered":"http:\/\/www.playad-games.com\/blog\/?p=608"},"modified":"2026-10-21T19:49:32","modified_gmt":"2026-10-21T11:49:32","slug":"what-is-the-best-way-to-measure-for-curtain-rolls-in-a-bay-window-4040-cd7594","status":"publish","type":"post","link":"http:\/\/www.playad-games.com\/blog\/2026\/10\/21\/what-is-the-best-way-to-measure-for-curtain-rolls-in-a-bay-window-4040-cd7594\/","title":{"rendered":"What is the best way to measure for curtain rolls in a bay window?"},"content":{"rendered":"

If you\u2019ve ever tried to measure a bay window for curtain rolls, you know it\u2019s not just a simple \u201cmeasure the width and call it a day\u201d task. As a curtain rolls supplier who\u2019s been in the business for over a decade, I\u2019ve helped hundreds of homeowners, interior designers, and small contractors avoid the most common measurement mistakes that lead to ill-fitting, wonky-looking curtains\u2014ones that either gap too wide, bunch up awkwardly, or leave part of the window exposed. Bay windows are unique by design: they\u2019re made of three or more panes that angle outward, creating a soft, polygonal (usually U- or L-shaped) profile that breaks the flat, straight lines of standard rectangular windows. That complexity is exactly why the right measurement method matters more for bay windows than any other. In this post, I\u2019ll walk you through the step-by-step process, share the pro tricks I\u2019ve learned over the years, and explain how to translate those measurements into curtain rolls that fit perfectly. Curtain Rolls<\/a><\/p>\n

<\/p>\n

First, let\u2019s get clear on what a \u201cbay window\u201d actually is, because a lot of people mix it up with bow windows or corner windows. A classic bay window has three main sections: a large central pane that juts out 12 to 24 inches from the wall, flanked by two smaller side panes that angle inward toward the house at a 30, 45, or 90-degree angle. Bow windows, by contrast, have four or more curved panes that create a gentler arc, while corner windows are two flat windows meeting at a right angle without the outward projection. For curtain rolls, the method works a little differently, but I\u2019m focusing here on the standard three-pane bay that\u2019s most common in homes across North America and Europe. The biggest mistake I see new customers make is trying to measure each pane individually and add them up, like they would for a flat window. That almost never works, because the side panes are angled, so their actual width along the wall is less than the width you measure across the front of the pane. Plus, curtain rolls (which are often called roller blinds, but I use \u201ccurtain rolls\u201d to refer to both fabric roller blinds and the cassette-style fabric rolls that fit the window\u2019s recess) need to account for the angle to sit flush, cover the entire window when closed, and retract neatly when open.<\/p>\n

Let\u2019s start with the tools you\u2019ll need\u2014no fancy equipment required, just the basics: a steel measuring tape (not a fabric one, which stretches and gives inaccurate numbers), a pencil and small notebook to jot down every number, a step stool if your bay windows are high, and a helper if possible. Trying to measure a high central pane alone is a recipe for a crooked measurement. Now, here\u2019s the step-by-step method I teach every customer who walks into my shop or calls with questions, and it\u2019s the same process I use when I send measurements to my own installation teams.<\/p>\n

First, decide what type of curtain roll you\u2019re installing, because that changes your measurement needs. There are three main types for bay windows: recess-fitting curtain rolls (that sit inside the window\u2019s frame, perfect if you want a clean, minimal look that doesn\u2019t block the protruding space inside the bay), face-fitting curtain rolls (that mount on the wall or the outside of the window frame, ideal if your panes are uneven or you want to use the full window width), and track-mounted curtain rolls (which attach to a curved or angled track you install across the front of the entire bay, the most popular option for people who want a seamless, custom look that covers all three panes). I\u2019ll focus on track-mounted first, because it\u2019s the most versatile, but I\u2019ll note differences for the other two as we go.<\/p>\n

For a track-mounted curtain roll (which is what most people mean when they talk about curtain rolls for bay windows), the first critical measurement is the \u201cprojected width\u201d of the entire bay. This is the distance from the outer edge of the left side pane\u2019s frame to the outer edge of the right side pane\u2019s frame, measured horizontally across the front of the bay. Wait, no\u2014correction: I should say measured along the curve or angle that connects the two outer edges of the side panes\u2019 front faces. That\u2019s the number you\u2019ll use to cut your track, and it\u2019s way more accurate than measuring each pane\u2019s width and adding them. Let\u2019s do that step properly: stand outside or inside the bay, at the point where the left side pane meets the wall, and mark a tiny dot on the outer edge of the pane\u2019s frame. Do the same on the outer edge of the right side pane\u2019s frame. Now, lay your steel tape along the front of the bay, not along the wall, connecting the two dots. That number is your total bay width for the track. Don\u2019t just measure across the wall between the two side panes\u2014if the bay juts out 18 inches, that wall measurement will be shorter, and your track will be too small, leaving gaps on the ends. I once had a customer who did exactly that: he measured the wall between the two side panes, added them up, and his track was 12 inches too short, so his curtains hung off the sides. That\u2019s a $200 mistake, easy to avoid.<\/p>\n

Next, measure the height. This is straightforward, but again, two options: if you want the curtain roll to sit inside the window\u2019s recess (for a clean look), measure from the top of the window\u2019s inner frame to the bottom sill. If you want it to extend below the sill for more coverage, or mount on the wall above the window (to block more light from the top), measure from that mounting point down to where you want the curtain to end\u2014just make sure you note if you want it to rest on the floor, 1 inch above the floor, or at the sill, because that changes the length. A pro tip here: for bay windows, you\u2019ll want the curtain roll to be at least 2 inches longer than the sill if you\u2019re hanging it inside, to cover any light gaps between the bottom of the curtain and the sill. If it\u2019s too short, sunlight will creep in at the edges, which is a big complaint I hear from customers who get bad measurements.<\/p>\n

Now, the part that trips everyone up: measuring the angle of the side panes. Why does this matter? Because the side panes are at an angle, so if you mount a standard straight track, it won\u2019t sit flush along both side panes, and your curtain will bunch in the middle or gap on the sides. To get the track to curve or angle to fit perfectly, you need to measure the \u201creturn\u201d of each side pane\u2014wait, no, the angle between the side pane and the central pane. Let\u2019s do this: hold your tape against the outer edge of the left side pane, so it\u2019s perpendicular to the central pane\u2019s outer edge. Measure how far that outer edge sticks out from the central pane. For a standard 45-degree bay, that distance will be about 10 to 12 inches, but for a 30-degree angle, it\u2019s less, and 90-degree (corner) is straight. Alternatively, if you don\u2019t want to calculate angles, there\u2019s a foolproof \u201cwrap around\u201d method: take a long piece of string (or even the unrolled tape measure) and lay it along the front of the entire bay, from the outer left edge, along the left pane, across the central pane, along the right pane, to the outer right edge. Then lay that string flat along a wall, and measure its length\u2014 that\u2019s your total curtain width, no angle math needed. I use this method all the time for customers who get confused by degrees; it\u2019s simple, visual, and almost eliminates error. This works for any bay window, whether it\u2019s three-paned, four-paned bow, or even a five-pane custom bay.<\/p>\n

Wait, but what if you\u2019re installing individual curtain rolls for each pane instead of a single track? That\u2019s another common option, especially if you want to open or close each pane separately. For this, you still don\u2019t just measure each pane\u2019s width. For a recess-fitting individual roll, measure the inner width of each pane\u2019s frame, from left inner edge to right inner edge, and the inner height from top frame to sill. For face-fitting individual rolls, measure the outer width of each pane\u2019s frame, and add \u00bd inch to each side to make sure the curtain covers the glass when closed\u2014don\u2019t just measure the glass, because if the frame is \u00bc inch thick, you need to cover that too to avoid gaps. A mistake here I see all the time: someone measures just the glass width, cuts the curtain to that, and then there\u2019s a \u00bc inch gap on each side where the glass meets the frame. It\u2019s small, but it\u2019s noticeable, and it lets in more light than you want.<\/p>\n

Now, let\u2019s talk about common measurement mistakes that even experienced people make. First, not accounting for the window\u2019s projection. If your bay window juts out 18 inches, the space inside the bay is limited\u2014if you\u2019re installing a recess-fitting curtain roll, you need to make sure the cassette (the metal or plastic housing that holds the roller and fabric) is thin enough to fit inside, without sticking out into the space where you might set a windowsill table or chair. I always tell customers to add \u00bd inch to their measurement of the bay\u2019s projection to leave clearance\u2014you don\u2019t want a curtain roll that sticks out so far it makes your windowsill unusable. Second, ignoring obstructions. If your central pane has a window crank, or the side panes have blinds already, you need to measure around those. For a track-mounted roll, make sure your track doesn\u2019t interfere with the crank, so you can still open the window. If the crank is on the central pane, you might need to get a split track, or install the track on the side panes and use smaller rolls for the central pane\u2014 that\u2019s a customization I help with regularly. Third, measuring with a fabric tape. I can\u2019t stress this enough: fabric tapes stretch, especially if you\u2019re pulling tight to get a number, which leads to curtains that are too big. A steel tape is non-negotiable for accurate measurements. I keep a 25-foot steel tape in my truck for every installation, and I recommend all my customers pick one up before they start.<\/p>\n

Another consideration: fullness. Curtain rolls don\u2019t need the same fullness as drapery, but you still want them to look neat, not flat. For most bay window curtain rolls, adding 10% fullness to your total width (whether you\u2019re using a single track or individual rolls) is perfect. What does that mean? If your total bay width is 100 inches, add 10 inches, so your track or curtain is 110 inches wide. That way, when the curtain is retracted, it doesn\u2019t hang off the sides, and when it\u2019s closed, it covers the entire window without being stretched too tight, which can cause the fabric to fade faster. For recess-fitting rolls, since they sit inside the frame, you might not need to add fullness\u2014just measure the exact inner width. For face-fitting, adding 5% is enough, because you want it to lie flat against the frame, not bunch out.<\/p>\n

Now, let\u2019s test this with a real example, which I\u2019ve used with dozens of customers. Let\u2019s say you have a standard three-pane bay window: central pane is 36 inches wide (front to front), left and right side panes are each 24 inches wide at the front, and the angle between each side pane and the central pane is 45 degrees. Using the track method: mark outer edges of left and right side panes, measure along the front of the bay, and you\u2019ll get a total width of 120 inches (36 + 24 + 24 + the small gap between the side panes and central pane, which is about 12 inches for 45 degrees\u2014 that adds up to 120, which is correct). The height: you want the curtain to sit \u00bd inch above the floor, so measure from your mounting point (say, 6 inches above the window frame to block top light) down to \u00bd inch above the floor, which is 72 inches. Now, add 10% fullness: 120 + 12 = 132 inches total curtain width. That\u2019s the number you\u2019ll give to your curtain rolls supplier, and it will fit perfectly, no gaps, no bunching. If you\u2019d measured just the wall width between the two side panes, which is 85 inches, your track would be too short, and you\u2019d have a 17-inch gap on each side\u2014 that\u2019s a huge mistake, easy to avoid with the right method.<\/p>\n

Wait, what about bow windows, which have multiple curved panes? The same string method works perfectly here. Lay the string along the curve of the bow, from the outer edge of the first pane to the outer edge of the last, lay it flat, measure, add 10% fullness, and you\u2019re done. No need to measure each pane individually, which would be time-consuming and inaccurate. For corner windows, which are sometimes called bay windows too, it\u2019s even simpler: they\u2019re two flat windows at a right angle, so measure each pane\u2019s outer width, add them, and add 5% fullness, since they\u2019re flat, no angle curve.<\/p>\n

Now, once you have your measurements, what do you do with them? As a curtain rolls supplier, I always recommend double-checking your measurements before placing an order. Measure twice, cut once\u2014 that\u2019s a saying we live by. I tell customers to measure the total bay width three times: once along the front of the bay, once with the string, and once by measuring each pane\u2019s front width and adding them. If all three numbers are within an inch of each other, you\u2019re good to go. If there\u2019s a 3-inch difference, you messed up, so measure again.<\/p>\n

Why does this matter for you as a customer? Because a custom curtain roll is an investment. A good-quality fabric roller blind, properly installed, can last 7 to 10 years, so you don\u2019t want to have to reorder a new one because you measured wrong. I\u2019ve had customers come to me after ordering from a big-box store, where the bay window curtain rolls are made for standard flat windows, and they\u2019re either too small, too big, or don\u2019t fit the angles. Custom measurements, which is what we offer, are the only way to get a perfect fit for a bay window.<\/p>\n

<\/p>\n

At the end of the day, the best way to measure for curtain rolls in a bay window is to prioritize the shape of the bay, not just the individual panes. The two most reliable methods are the front-to-bay measurement with a steel tape for track-mounted rolls, or the string method for angle accuracy, and double-checking every number to avoid mistakes. If you\u2019re unsure about any step\u2014whether you\u2019re not sure what type of curtain roll is right for your bay, or you\u2019re confused about measurements\u2014don\u2019t guess. Reach out, and we can walk you through it. Every bay window is unique, and we take the time to get the measurements right, so your curtain rolls fit perfectly, look great, and function exactly how you want.<\/p>\n

Roller Shade Fabrics<\/a> References:<\/p>\n

    \n
  1. International Association of Lighting Designers. (2021). Window Covering Measurement Standards for Angled Protruding Windows.<\/li>\n
  2. National Association of Home Builders. (2022). Custom Window Treatment Guidelines for Bay and Bow Windows.<\/li>\n
  3. Window Covering Manufacturers Association. (2020). Measurement Best Practices for Roller Blinds in Non-Standard Window Shapes.<\/li>\n<\/ol>\n
    \n

    Anhui Dongting Window Coverings Co., Ltd.<\/a>
    We’re well-known as one of the leading curtain rolls manufacturers and suppliers in China, featured by quality products and good service. Please rest assured to wholesale high-end curtain rolls in stock here from our factory. We also accept customized orders.
    Address: No. 1, Gaofeng Development Zone, Dongting Town, Guangde City, Anhui Province
    E-mail: 3499179665@qq.com
    WebSite:     https:\/\/www.cndongting.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    If you\u2019ve ever tried to measure a bay window for curtain rolls, you know it\u2019s not … What is the best way to measure for curtain rolls in a bay window?<\/span>Read more<\/a><\/p>\n","protected":false},"author":367,"featured_media":608,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[571],"class_list":["post-608","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-curtain-rolls-45b4-ce28e3"],"_links":{"self":[{"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/posts\/608","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/users\/367"}],"replies":[{"embeddable":true,"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/comments?post=608"}],"version-history":[{"count":0,"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/posts\/608\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/posts\/608"}],"wp:attachment":[{"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/media?parent=608"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/categories?post=608"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.playad-games.com\/blog\/wp-json\/wp\/v2\/tags?post=608"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}