How to Measure Windows for Shutters: A Delmarva Homeowner’s Guide

TL;DR: To measure for shutters, first choose your mount style (inside or outside). For an inside mount, measure the width and height at three different points (top, middle, bottom and left, center, right) and use the smallest measurement for each. For an outside mount, measure the area you want to cover and add 1.5-2 inches to each side for overlap. Always use a steel tape measure and account for any obstructions. For a guaranteed perfect fit in your Delmarva home, the experts at Home Blinds & Floors offer free in-home consultations.

Ready to give your windows a timeless upgrade with beautiful custom shutters, but not sure where to start with measuring? At Home Blinds & Floors, we help homeowners across the Eastern Shore navigate this crucial first step to ensure a flawless fit. Getting precise measurements is the key to achieving that polished, built-in look you want for your home, whether you're in Salisbury, MD, or Rehoth Beach, DE. This guide will walk you through the process just like a pro.

Why Accurate Shutter Measurements Are Critical

Ever wonder why a tiny 1/16th of an inch can make or break a shutter installation? We've seen it firsthand helping homeowners all across the Delmarva Peninsula. Precision is the name of the game. Custom shutters are built to the exact specifications of your window opening, so even a small mistake can result in annoying gaps, shutters that don't operate smoothly, or—worst-case scenario—a shutter that just plain won't fit.

Getting it right from the very beginning protects your investment and ensures you get that polished, high-end look you're after. A perfectly measured shutter doesn't just look better; it also delivers far superior light control, privacy, and insulation. The first big decision—whether to go for a sleek, built-in inside mount or a more forgiving outside mount—is entirely dictated by those initial numbers.

Key Factors For Success

Before you even touch a tape measure, a few foundational concepts will set you up for success. This advice holds true whether you're in Salisbury, MD, or relaxing in Rehoboth Beach, DE.

• Decide on Your Mount Style First. This is critical. Your measuring approach changes completely depending on if you want an inside mount (which fits neatly inside the window frame) or an outside mount (which attaches to the wall or trim around the window).

• Grab the Right Tool. A steel tape measure is non-negotiable. Don't even think about using a fabric or flexible tape—they can stretch and will give you inaccurate readings every time.

• Measure Thrice, Order Once. I've been in thousands of homes, and I can tell you that windows are almost never perfectly square. Measuring the width at the top, middle, and bottom, and then the height at the left, center, and right, is the only way to account for these subtle (and sometimes not-so-subtle) variations.

From free in-home consultations to flawless installation, Home Blinds & Floors takes the stress out of selecting window treatments. Our experts ensure every measurement is perfect, so you can enjoy beautiful, custom-fit plantation shutters that last.

For a deeper look into the benefits of this timeless window treatment, check out our ultimate guide to plantation shutters for Delmarva homes. It gives you more context on why shutters are such a smart investment for any Eastern Shore property.

Choosing Your Mount Style: Inside vs. Outside

Before you even think about measuring, let's talk about getting prepared. A perfect shutter fit starts with having the right gear on hand. Trust me, trying to get an accurate reading while fumbling for a pencil is a recipe for frustration.

Here’s what you'll need:

• A good steel tape measure. This is non-negotiable. Don't even think about using a cloth or plastic one—they can stretch and throw off your numbers. A solid, 25-foot steel tape is your best friend here.

• Pencil and a notepad. Don't try to be a hero and remember the numbers. Write everything down immediately. When you're measuring multiple windows, they all start to blend together.

• A sturdy step ladder. For any window that's even slightly out of reach, safety first. A wobbly chair just won't cut it when you're trying to get a precise measurement.

• A level. You’d be surprised how many windows, especially in older Delmarva homes, aren't perfectly square. A level tells you the truth about your window frame before you get too far along.

Once you've got your tools, you're at the most important fork in the road: deciding on your mount style. This single choice changes how you'll measure and dramatically affects the final look.

Inside Mount vs. Outside Mount

Your two options are inside mount and outside mount. Let's break down what that really means.

An inside mount is exactly what it sounds like—the shutter fits neatly inside the window casing. It gives you a clean, built-in look that really lets your existing window trim shine. It’s a beautiful, popular choice for a reason. But there's a catch: it requires enough unobstructed depth in the window frame for the shutter to fit without hitting the glass or any cranks.

On the other hand, an outside mount is installed on the wall or trim around the window opening. This is my go-to solution for windows that are too shallow, have obstructions like alarm sensors or cranks, or are noticeably out of square. An outside mount can also make a window feel larger and does a fantastic job of blocking out light.

Expert Insight: Honestly, the decision often comes down to practicality. Everyone loves the sleek appearance of an inside mount, but it's only an option if your window has the necessary depth. An outside mount is the ultimate problem-solver for those tricky windows we see all the time.

As a local, family-run business, Home Blinds & Floors provides personal service, competitive pricing, and professional installation throughout Sussex, Wicomico, Kent, and beyond. We help homeowners in Salisbury and Rehoboth Beach navigate these choices every day during our free in-home consultations.

Making the Right Choice for Your Windows

So, how do you pick? It almost always boils down to window depth. From my experience, an inside mount shutter needs a minimum recess of about 2 to 2.5 inches to comfortably fit the frame and allow the louvers to operate. That's why checking your window's depth should be the very first measurement you take.

If you find your window recess is too shallow, don't sweat it. An outside mount looks just as elegant and accounts for roughly 35-40% of the shutter installations we do, especially in homes with more unique or historic character.

To keep all your numbers straight, you'll want a good system. Check out our guide on creating a perfect window measuring template for Delmarva homes. It’s a lifesaver for keeping your measurements organized and accurate.

Inside Mount vs. Outside Mount Shutters

Choosing the right mount style is crucial for homeowners on the Delmarva Peninsula, as it impacts everything from aesthetics to light control. This table should help clarify the key differences and guide you toward the best fit for your home.

Feature	Inside Mount	Outside Mount
Aesthetic	Clean, built-in, and minimalist.	Creates a bold frame, making windows appear larger.
Window Trim	Showcases existing decorative molding.	Covers the window trim completely.
Light Control	Good, but may have slight light gaps at the edges.	Excellent, as it overlaps the opening for superior light blockage.
Requirements	Needs sufficient, unobstructed window depth.	No depth requirement; great for shallow windows.
Best For	Windows with beautiful trim and adequate recess depth.	Windows that aren't square, are shallow, or have obstructions.

Ultimately, whether you choose an inside or outside mount, the goal is a beautiful, functional result. Considering these factors will set you on the right path for a perfect installation.

Measuring for a Flawless Inside Mount

If you’re after that clean, built-in look that plantation shutters are known for, an inside mount is the way to go. This style tucks the shutter neatly inside the window casing, highlighting your existing trim for a truly seamless finish. But getting that beautiful result hinges on one thing: perfect measurements. There’s almost no wiggle room.

Don't let that intimidate you. With a methodical approach, you can get the numbers you need. The most important thing to remember is that almost no window is perfectly square, whether your home is in Ocean City or Easton. Houses settle, and even new builds have quirks. That’s why we always use the "rule of three" for every measurement.

This infographic gives you a great overview of what to do before you even grab your tape measure, from getting your tools ready to picking a mount style.

As you can see, good preparation is half the battle. A clear plan makes the actual measuring process much smoother.

Applying the Rule of Three for Width

First up is the width. You’ll need to measure the window opening in three different spots—don't just take one measurement from the middle and call it good.

• Top: Measure the width straight across the top of the window frame, from one inside edge to the other.

• Middle: Do it again, right in the center of the window.

• Bottom: Finally, take one last measurement across the bottom.

Write down all three numbers, being as precise as possible—down to the nearest 1/16th of an inch. No rounding! Once you have them, circle the smallest number. This is the most critical figure for your width, as it guarantees the shutter will fit into the tightest part of the opening without scraping or getting stuck.

Finding the Correct Height

The process for height is exactly the same. Taking three vertical measurements ensures you account for any little dips or rises in the windowsill or header.

• Left Side: Measure the height from the sill to the top of the frame on the far-left side.

• Center: Take the same measurement right down the middle of the window.

• Right Side: Get your last height measurement on the far-right side.

Again, jot down all three numbers precisely. And just like you did for the width, find and circle the smallest of the three height measurements. Using the tightest dimensions for both width and height is the industry secret to a perfect inside mount.

From free in-home consultations to flawless installation, Home Blinds & Floors takes the guesswork out of the process. Our experts do this every day, ensuring a perfect fit for homes all over the Delmarva peninsula.

Checking for Window Squareness

You’ve got your width and height, but there's one last check: squareness. An out-of-square window can leave ugly gaps around an inside-mounted shutter. The test is simple—just measure the window diagonally.

• Measure from the top-left corner to the bottom-right corner.

• Then, measure from the top-right corner to the bottom-left corner.

If those two diagonal numbers are different by more than 1/4 of an inch, your window has a significant tilt. It's a common issue, and in these cases, an outside mount is usually a much better option because it will hide those imperfections completely.

Pro Tip: The accuracy of these measurements is everything. Taking three width and three height measurements and using the smallest of each is the non-negotiable industry standard. It’s what separates a DIY-look from a professional one. Find more professional guidelines on measuring for window treatments to see how the pros do it.

Accounting for Obstructions

Before you put your tape measure away, take one last look at your window. Is there anything that could get in the way of the shutter? I'm talking about things like:

• Window cranks

• Alarm system sensors

• Locks and latches

• Any trim that juts into the opening

Measure the depth from the front edge of your window casing back to the first thing you'd hit. Most inside mount shutters need a certain amount of unobstructed depth so the louvers can actually tilt open and closed. If something is blocking that space, an outside mount might be your only choice.

Home Blinds & Floors offers a wide selection of custom blinds and shades in Delmarva, with expert installers who bring the showroom to your living room. We can spot these tricky situations during a free consultation and recommend the best, most beautiful solution for your specific windows.

Mastering the Outside Mount for Any Window

So, what do you do when your windows just aren't deep enough for an inside mount? Or maybe they have some beautiful, ornate trim you'd rather cover up for a cleaner, more modern look. This is exactly where an outside mount comes in, and it's an elegant, versatile solution we use in homes all across the Delmarva Peninsula.

With an outside mount, you're not measuring the opening you want to fill. Instead, you're measuring the area you want to cover. This simple shift in thinking makes all the difference.

It's the ultimate problem-solver. An outside mount works beautifully for windows that are slightly out of square—a common quirk we see in older homes from Easton to Lewes. It also gives you much better light control and privacy because the frame overlaps the window opening, which gets rid of those pesky light gaps you sometimes see with inside-mount treatments.

Getting the Frame Overlap Just Right

The secret to a great-looking outside mount is nailing the overlap. You want the shutter frame to extend beyond the window opening just enough to look intentional and balanced. If the overlap is too small, it can look a bit awkward. Too much, and you risk overwhelming the window itself.

Start by measuring the total width of the window, including any trim or molding you plan on covering. Once you have that "total area" width, you'll add a little extra for the overlap. A good rule of thumb is to add 1.5 to 2 inches on each side.

• For example: Let's say your window, including the trim, measures 36 inches wide. You’d add 1.5 inches to the left and 1.5 inches to the right, for a total of 3 inches. That makes your final shutter width 39 inches.

Calculating the Correct Height

Measuring for height follows the same logic. Measure the full height of the area you want the shutter to cover, from the very top of the trim down to the bottom of the windowsill. Just like you did with the width, you'll add a bit for overlap.

Add another 1.5 to 2 inches to both the top and the bottom of your total height measurement. This ensures the shutter frame extends past the opening, giving you that critical light coverage and a stately, finished appearance.

• For example: If the total height, including the sill and top trim, is 60 inches, adding 1.5 inches to the top and another 1.5 inches to the bottom (3 inches total) brings your final order height to 63 inches.

Keep in mind that while the principles are similar, the process for how to measure windows for shutters is distinct from measuring for other treatments. If you're considering multiple options, it’s helpful to understand the differences. You can learn more by checking out our guide on how to measure windows for blinds, which details the unique requirements for those products.

A Few Things to Look Out For

Before you lock in those numbers, take a good look at the wall space surrounding your window. Are there any potential roadblocks that could get in the way of the shutter frame?

Be on the lookout for potential obstacles:

• Walls or corners that are too close

• Bookshelves or built-in furniture right next to the window

• Light fixtures or other decorative elements that stick out

• Nearby doors or other windows that might interfere

You need to have enough flat, clear wall space to handle the extra width and height you’ve added. If things are a little tight on one side, you might need to adjust your overlap for a custom fit. Honestly, this is where having an expert take a look can be a real game-changer.

From free in-home consultations to flawless installation, Home Blinds & Floors takes the stress out of getting new window treatments. Our team helps homeowners across Salisbury, Rehoboth Beach, and beyond master even the trickiest measurements, ensuring every custom shutter fits perfectly and looks absolutely stunning.

Handling Specialty Windows and Exterior Shutters

Many homes across the Delmarva Peninsula have beautiful, non-standard windows that give them character. From elegant arched windows in Lewes to classic bay windows in Salisbury, these special shapes require a bit more finesse than a standard rectangle. Your usual width and height measurements just won't cut it.

Measuring these architectural features can feel intimidating, but it’s entirely doable. For most unique shapes, the secret is to create a simple template.

As a local, family-run business, Home Blinds & Floors has seen it all. We love helping homeowners find the perfect shutters for every window, no matter how complex the shape or size might seem.

Measuring Arched Windows and Unique Shapes

When you’re dealing with an arched or circular window, a paper template is your best friend. Start by taping a large piece of sturdy paper—butcher paper or contractor's paper works great—over the entire window opening. Then, just trace the exact shape of the window directly onto the paper.

Once you have your tracing, carefully cut out the template. This physical pattern is exactly what the manufacturer needs to create a shutter that fits like a glove. To be extra sure, I always recommend taking a few key measurements directly from your template:

• Maximum Width: Find the widest point of the arch and measure it.

• Total Height: Measure from the very top of the arch straight down to the sill.

• Springline Height: This is a crucial one. It’s the height from the sill to the point where the window starts to curve.

Conquering Bay and Corner Windows

Bay windows are fantastic for adding light and dimension, but those angles can be tricky. The key is to treat each window panel within the bay as its own separate window. Go through the standard inside mount measurement process for each individual section.

The most critical part here is getting the angles right where the windows meet. You’ll absolutely need a protractor or an angle finder for this. Documenting these angles precisely is the only way to ensure the shutter frames will meet up perfectly at the corners for a seamless, professional-looking finish.

Expert Takeaway: Measuring specialty windows is less about a list of numbers and more about capturing the true shape. A well-made template for an arch or precise angle measurements for a bay window is far more valuable than a series of width and height figures alone.

A Different Approach for Exterior Shutters

While interior shutters are all about that perfect, snug fit, exterior decorative shutters play by a different set of rules. Their job is all about aesthetics—boosting curb appeal and adding architectural character. You’re not aiming for a tight seal; you're aiming for visual harmony.

There’s a long-standing design principle for getting the size just right. An important rule of thumb for decorative exterior shutters is that each shutter panel should be about 25% to 33% of the entire window width, including the frame. So, for a 60-inch-wide window, each shutter should be between 15 and 20 inches wide to look authentic. This proportion has been part of architectural tradition for centuries, and getting it wrong can really throw off your home's look.

When you’re measuring, first get the full height of your window from the top of the trim to the bottom of the sill—the shutter should match this exactly. Next, measure the full width of the window opening, trim included, and divide that number by four. This gives you the ideal width for each of your two shutter panels, making them look as if they could actually close and cover the window.

While we're focused on the outside, you can explore a variety of beautiful interior options in our guide to the top 7 types of indoor shutters for your Delmarva home.

Avoiding Common Pitfalls and Knowing When to Call a Pro

Measuring for shutters feels straightforward, but a few common slip-ups can turn a simple project into a real headache. I’ve seen it all over the years. A tiny miscalculation at the start can easily lead to shutters that don't fit, project delays, and money down the drain. The good news is that knowing what to watch out for is half the battle.

The most frequent mistake? Using the wrong measuring tape. That floppy cloth or vinyl tape from your sewing kit might seem fine, but it can stretch and throw off your numbers. You absolutely need a solid, steel tape measure for this job—no exceptions. Another classic oversight is skipping the "is it square?" check. Taking those two quick diagonal measurements will tell you instantly if your window frame is crooked. If it is, an inside mount will likely leave you with ugly gaps, making an outside mount the smarter play.

Finally, people often forget about the things that stick out. Window cranks, alarm sensors, and even thick, decorative sills can get in the way of the shutter frame or stop the louvers from opening properly. Your numbers might be perfect on paper, but if you haven’t accounted for these real-world obstacles, you're in for a frustrating surprise on installation day.

Knowing When to Get Expert Help

While tackling a standard rectangular window is a great DIY win, some situations just scream for a professional. Trust me, trying to measure complex or tricky windows yourself can lead to expensive mistakes that cost far more than a professional consultation would have.

Here are a few scenarios where it's best to pick up the phone:

• Unusual Window Shapes: Think arches, circles, sunbursts, or angled windows. These require precise templates and a bit of geometry that goes way beyond a simple width and height measurement.

• Massive or Hard-to-Reach Windows: Trying to measure that huge picture window or a second-story dormer isn't just difficult—it can be a safety risk. Getting perfect accuracy while perched on a ladder is next to impossible.

• Whole-Home Shutter Projects: If you're outfitting your entire home in Salisbury or Rehoboth Beach, the sheer number of windows multiplies the chances of making a mistake. One bad measurement can disrupt the timeline and budget for the entire project.

• Seriously Out-of-Square Frames: If your diagonal measurements are off by more than 1/4-inch, it’s time for an expert. They’ll know the best way to handle it, whether that means a specific outside mount frame or a custom build-out to hide the imperfection.

To help you decide, here’s a quick checklist that many of our Delmarva clients have found useful.

DIY vs. Professional Measurement Checklist

This simple checklist can help you weigh the pros and cons and decide whether to grab your tape measure or schedule a professional to visit your home.

Consideration	Best for DIY Measurement	Best for Professional Measurement
Window Shape	Standard rectangles and squares.	Arches, circles, bay windows, or angled shapes.
Window Size & Location	Standard size, easily accessible from the floor.	Very large, oversized, or high-up windows requiring a ladder.
Project Scope	One or two simple windows.	A full room, multiple rooms, or a whole-home project.
Window Condition	Perfectly square (diagonals are equal).	Out-of-square by more than 1/4-inch; has obstructions.
Your Comfort Level	Confident with tools and precise measurements.	You prefer a guarantee and want zero risk of costly errors.

Ultimately, calling a pro is about buying peace of mind. It’s a small investment to guarantee the job is done right the first time.

At Home Blinds & Floors, our expert installers bring the showroom right to you. Our free in-home consultation removes all the guesswork and risk, ensuring every single measurement is flawless. We handle the tricky parts so you can focus on the fun part—choosing a style you'll love.

To get a better handle on your budget, check out our guide to understanding your shutter installation cost in Delmarva.

FAQs on Measuring Windows for Shutters

How much depth do I need for inside mount shutters?

For most plantation shutters, you need a minimum unobstructed window depth of about 2.5 inches. This ensures the shutter frame can be installed properly and the louvers have enough clearance to tilt open and closed without hitting the glass. If your windows are more shallow, an outside mount is an excellent alternative.

Should I round my measurements to the nearest inch?

No, never round your measurements. For custom window treatments, precision is key. You should always measure to the nearest 1/16th of an inch. Providing the most accurate numbers possible ensures your custom shutters will be manufactured for a perfect, professional fit.

Do I need to make deductions for clearance myself?

You do not. Your job is to provide the exact, tightest measurements of your window opening for an inside mount, or the exact coverage area for an outside mount. The manufacturer will take the necessary small deductions (usually 1/16" to 1/8") to ensure the shutter fits and operates perfectly within that space.

Are plantation shutters a good investment for Delmarva homes?

Absolutely. Plantation shutters are one of the few window treatments that can increase your home's resale value. They offer excellent durability, energy efficiency by insulating windows, superior light control, and a timeless aesthetic that complements the classic style of many homes on the Eastern Shore.

What cities in Delmarva do you serve?

Home Blinds & Floors proudly serves homeowners and businesses across the Delmarva Peninsula. Our primary service areas include Salisbury, Ocean City, and Berlin in Maryland, and Rehoboth Beach, Lewes, Bethany Beach, and surrounding communities in Delaware. We bring the showroom to you with our free in-home consultations.

In summary, Home Blinds & Floors provides custom window treatments, expert advice, and in-home service to homes across the Delmarva Peninsula. From Rehoboth Beach to Easton, our team is here to help you choose the best shades, shutters, or blinds for your space. Schedule your free consultation today.