How to Measure Window Blinds: A Simple Guide

Ever stared blankly at your window, a measuring tape in hand, feeling utterly lost when trying to figure out what size blinds you actually need? You’re not alone! Ill-fitting window blinds can not only look awkward, leaving unsightly gaps or being too short, but can also compromise light control, privacy, and even energy efficiency in your home. Getting accurate measurements is the crucial first step towards a stylish and functional window treatment that complements your space perfectly.

Investing in new blinds is an investment in your home’s aesthetic and comfort. Accurate measurements ensure you order the correct size, avoiding costly mistakes, time-consuming returns, and the frustration of blinds that just don’t fit. By taking the time to measure properly, you’ll guarantee a professional-looking installation and enjoy the full benefits of your new window coverings for years to come.

What tools do I need, and how do I decide whether to measure for inside or outside mount?

What’s the difference between inside and outside mount measurements?

The key difference lies in where the blind or shade is installed: an inside mount fits *inside* the window frame, requiring precise measurements of the window opening, while an outside mount is installed *outside* the window frame, typically on the wall or window trim, allowing for overlap to maximize light control and privacy.

When measuring for an inside mount, you’ll measure the exact width and height of the window opening *within* the frame. It’s crucial to measure at the top, middle, and bottom for width, and left, middle, and right for height, noting the smallest measurement for each. This ensures the blind or shade will fit snugly inside the frame without rubbing or binding. Deductions are often made by the manufacturer to account for the operating mechanisms and ensure a smooth fit. Therefore, it’s important to provide the *exact* window opening measurements, and let the manufacturer handle any necessary deductions. For an outside mount, you’ll measure the area you want the blind or shade to cover beyond the window frame. This measurement should account for the desired overlap on all sides (typically 1-3 inches) to block light and ensure privacy. The extra overlap ensures that light doesn’t seep through the sides of the blind. When deciding on the amount of overlap, consider the style of the blind, the look you want to achieve, and the amount of light you need to block. An outside mount can also be useful for windows without sufficient depth for an inside mount, or to make a window appear larger.

How do I measure for blinds on a recessed window?

To accurately measure for blinds in a recessed window (meaning the window is set back into the wall), measure the width and height inside the recess at the top, middle, and bottom. Use the narrowest width and the shortest height measurements to ensure a proper fit within the recess. These are your order measurements, and the blind manufacturer will typically make slight deductions to ensure smooth operation.

When measuring the width, use a steel measuring tape for accuracy. Check the width at the top, middle, and bottom of the window recess. If the measurements are different, use the smallest width. This is crucial because the blind needs to fit within the tightest point of the recess. Similarly, measure the height (or drop) of the window in three places: left, center, and right. Again, use the shortest measurement as your order height. Remember to specify that you are providing “recess” measurements when placing your order. Most blind manufacturers will automatically deduct a small amount (typically ¼ to ½ inch) from the width to allow for easy installation and operation without binding. However, clarifying this detail with the manufacturer will prevent any misunderstandings and ensure you receive blinds that fit perfectly in your recessed window.

Should I round up or down when measuring for blinds?

Generally, when measuring for blinds, you should round *down* to the nearest 1/8 inch for the width, especially for inside mount blinds. This ensures a comfortable fit within the window frame, preventing the blinds from rubbing or getting stuck. For height, round up, but only if necessary to meet a minimum height requirement if noted.

Rounding down on the width allows for slight imperfections in the window frame. Windows are rarely perfectly square, and attempting to force blinds that are too wide into the opening can cause damage to the blinds, the window frame, or both. A small gap on either side is preferable to blinds that won’t fit. Blinds manufacturers often take a small deduction from your specified width to ensure a proper inside fit. For outside mount blinds (mounted on the wall or trim surrounding the window), the width measurement is more about coverage and personal preference. In this case, you’ll want the blinds to extend beyond the window opening on each side to block light effectively. If you’re between measurements, rounding up will provide better light blockage and a more finished look. Just make sure there is enough wall space to accommodate the extra width. Remember that the headrail and the blind itself will be this width.

How accurate do my blind measurements need to be?

Your blind measurements need to be accurate to within 1/8 of an inch (0.125 inches) for a proper fit. While some manufacturers are more forgiving than others, aiming for this level of precision minimizes gaps, ensures smooth operation, and prevents installation headaches. For inside mount blinds, especially, accuracy is paramount.

The reason for this precision is simple: even a slightly inaccurate measurement can lead to problems. If your blinds are too wide, they won’t fit within the window frame for an inside mount. If they’re too narrow, you’ll have unsightly gaps on either side, reducing light control and privacy. With outside mount blinds, being off by more than 1/8 inch can mean the blind doesn’t fully cover the window opening, defeating the purpose of improving light control or achieving a desired aesthetic.

To achieve this level of accuracy, use a good quality steel measuring tape, not a cloth one, which can stretch and distort. Double-check each measurement, and if you’re unsure, it’s always better to err on the side of slightly smaller, especially for inside mount blinds. Many retailers will take a small deduction (usually 1/4 to 1/2 inch) from your specified width for inside mount blinds to ensure a perfect fit, but it’s still best to provide the most accurate window opening measurement you can. Remember to measure each window separately, as window sizes can vary slightly throughout your home.

What’s the best way to measure for blinds if my window isn’t perfectly square?

When dealing with windows that aren’t perfectly square, measure the window in three places for both width and height: top, middle, and bottom for width, and left, middle, and right for height. Use the smallest width and the largest height of these measurements when ordering inside-mount blinds. This ensures the blind will fit without being too tight or too short. For outside-mount blinds, use the largest width and height to ensure full coverage.

The reason for taking multiple measurements is to account for any inconsistencies. Walls and window frames settle over time, leading to slight variations. By identifying the narrowest width, you avoid ordering a blind that’s too wide to fit within the frame. Conversely, using the largest height ensures the blind completely covers the window opening, even if the frame is slightly uneven. This approach prevents gaps and ensures a more aesthetically pleasing and functional result.

It’s also crucial to specify to the blind manufacturer or retailer that your window is not perfectly square. They might have specific recommendations based on the type of blind you’re purchasing. Some blind types, like vertical blinds, offer more forgiveness with slightly uneven windows compared to others, such as cellular shades. Communicating this information upfront can prevent costly mistakes and ensure a better fit and overall experience.

What happens if I measure my windows wrong for blinds?

Measuring your windows incorrectly for blinds can lead to several problems, ranging from blinds that don’t fit at all to blinds that fit poorly and don’t function correctly. Ultimately, incorrect measurements mean you’ll likely need to reorder, incurring additional costs and delays, or be stuck with blinds that are unusable.

If your blinds are too narrow, they won’t cover the entire window opening, allowing light to seep through on the sides and compromising privacy. If they’re too wide, they may not fit within the window frame at all, or they could rub against the sides, making them difficult to raise and lower. If you’ve ordered inside-mount blinds that are too short, they won’t reach the bottom of the window. Blinds that are too long will bunch up at the bottom, creating an unsightly appearance. The tolerance for errors is generally very small – often less than half an inch – which underscores the need for precision.

Furthermore, some retailers have strict return policies on custom-made blinds ordered to your specifications. If the measurement error is your fault, you may not be able to return or exchange the blinds, leaving you with a product you can’t use and a wasted investment. Always double-check your measurements, follow the specific instructions provided by the blind manufacturer or retailer, and consider getting a professional to measure your windows if you’re unsure.

How do I measure for blinds on a bay window?

Measuring for blinds in a bay window requires individual measurements for each window pane, taking into account the angles and desired overlap. Measure the width and height of each window separately, decide if you want inside or outside mounts, and factor in deductions for inside mounts to ensure proper operation, and overlaps for outside mounts for light control and privacy.

First, determine whether you want an inside mount (blinds installed within the window frame) or an outside mount (blinds installed on the wall or trim surrounding the window). For an inside mount, measure the width of the window frame at the top, middle, and bottom, using the narrowest measurement. Then, measure the height of the window frame on the left, center, and right sides, using the longest measurement. This ensures the blinds will fit within the frame. Important: the manufacturer will often deduct a small amount (usually 1/4 to 1/2 inch) from your width measurement to allow for smooth operation. Check the manufacturer’s specifications for their deduction policy.

For an outside mount, measure the width and height of the area you want the blinds to cover. Add several inches (typically 2-4 inches on each side and 2-4 inches at the top) to the width and height to minimize light gaps and maximize privacy. Note the angles of the bay window walls where they meet so that you can choose the appropriate headrail and bottom rail options when ordering your blinds. Some manufacturers offer specific bay window headrails designed to create a seamless look.

And that’s all there is to it! Measuring for window blinds might seem daunting at first, but with these simple steps, you’ll be well on your way to finding the perfect fit. Thanks for reading, and we hope this guide has been helpful. Feel free to stop by again for more home improvement tips and tricks!