How to Measure for Exterior Shutters: Complete Sizing Guide
Article may have affiliate links. If you make a purchase, I may earn a tiny commission at no extra cost to you. Big thanks for supporting my small business.
Want to know the actual formula for sizing exterior shutters? Take your window width, divide by two. That’s how wide each shutter should be. Height? Match your window opening or go just below the top of the window frame. And whatever you do, never go taller than the actual window, that’s the fastest way to make your house look weird from the street!
Here’s the thing nobody tells you: there’s no such thing as “standard” shutter sizing. Your windows aren’t standard. Your trim isn’t standard. And that light fixture sitting two inches from your front window? Yeah, that changes everything.
When you get the measurements right, it completely transforms how your house looks. When you get them wrong? Everyone notices, even if they can’t quite put their finger on why something looks off.
The Basic Exterior Shutter Measurement Formula
- Shutter Width = Window width ÷ 2 (for each shutter)
- Shutter Height = Window opening height OR just below top of window frame
- Golden Rule = Shutters NEVER taller than your window
That’s it. Everything else is figuring out how to apply this to your specific situation.
Here is our small lake house before we installed new “wider and taller” windows.
What Size Exterior Shutters Do You Need?
When we started this project, we wanted shutters that looked intentional. We didn’t want standard off-the-shelf shutters, but custom would’ve cost more than our entire siding budget. So we made our own.
You can see exactly how we made these shutters by visiting this post, diy shutters (tutorial).
As you can see above, we removed the smaller older windows and installed new wider and taller windows, making the visual appeal from the street game changing!
Look at our double window below. The shutter height runs almost the full window opening length, and each shutter’s width is approximately half the width of one window pane. That’s the balance you’re after.
What Affects Exterior Shutter Size?
- Architectural style (Colonial, farmhouse, contemporary—each has different expectations)
- Window type (single, double hung, arched, bay windows)
- Function (decorative vs. actually closing for storm protection)
Notice our shutters don’t have frames. Most store-bought shutters come with frames that add 1-2 inches per side. Account for that frame width when measuring.
Step-by-Step Exterior Shutter Measurement Process
Step 1: Measure Window Width
Measure the window opening left to right. Take your window width and divide by 2. That’s your target width per shutter.
Real example: Our front window measured 40 inches wide. 40 ÷ 2 = 20 inches per shutter.
For double windows: Measure the full width of both windows combined, then divide by 4 (four shutters total).
Building your own? Check out our DIY shutter tutorial showing how we made these from pallet wood.
Step 2: Measure Window Height
Measure from the bottom of the window opening straight up. You have two options:
- Option 1: Top of the window opening (not including frame trim)
- Option 2: Just below the top of the window frame trim
Thin trim? Measure to the window opening. Wide, chunky trim? Extend to just below the top of the frame so shutters don’t look stubby.
How Far from Windows Should Exterior Shutters Sit?
Decorative shutters: Mount as close to the window as hardware allows—right up against the trim.
Functional shutters: Need 2-4 inches clearance so they can actually swing closed without scraping.
Common Exterior Shutter Measurement Mistakes
- Forgetting the frame: Store-bought shutters have frames adding 1-2 inches per side. Check product specs before ordering.
- Measuring glass only: Measure the entire window opening, including trim you want shutters to frame.
- Assuming windows match: Even in new construction, windows vary by inches. Measure every single window.
- Ignoring obstacles: Light fixtures, downspouts, outlets—check before measuring. Sometimes you need narrower shutters.
FAQ: Exterior Shutter Sizing
What are standard exterior shutter sizes?
Most manufacturers sell in 2-inch width increments (12″, 14″, 16″, 18″, 20″, 22″) and standard heights (36″, 48″, 60″, 72″). But measure anyway—”standard” doesn’t mean they’ll fit your specific windows.
What if measurements fall between sizes?
Round down if within an inch. Slightly too narrow is better than too wide. No one notices 1 inch narrower—everyone notices too wide.
Can exterior shutters be different sizes on the same house?
Yes. They probably should be if your windows are different sizes. The goal is proportional shutters for each window, not identical shutters everywhere.
Ready to Get Started?
- Measure every window (width and height)
- Do the math: width ÷ 2 per shutter
- Check for obstacles affecting placement
- Decide: buy pre-made or build your own
- Double-check numbers before ordering
If you’re considering making your own—which saves ridiculous money and isn’t as hard as it sounds—check out our complete DIY shutter tutorial with photos of every step.
The difference between properly measured shutters and “close enough” is the difference between your house looking professionally designed or like a DIY project gone wrong.
Take the extra 20 minutes to measure correctly!
More Lake House Projects You Will Love:
- Best Lake house Airbnb tour
- Lake house renovation – the start
- How high to hang kitchen cabinets – we removed and rehung the cabinets
- Lake house kitchen remodel on a budget – start to finish
- How to build a custom shower tile niche
- Living room remodel with Chantilly Lace White Paint
- DIY board and batten tutorial in a bedroom
- Knocking down a wall to make the living room bigger
Meet Jessica
What started as a hobby, Jessica’s blog now has millions of people visit yearly and while many of the projects and posts look and sound perfect, life hasn’t always been easy. Read Jessica’s story and how overcoming death, divorce and dementia was one of her biggest life lessons to date.
Come Enjoy a Stay at our Lake House
Our newly renovated waterfront lake house retreat with 1500 SF (7 beds), 3BR, 2BA, open concept living room + kitchen + lower level w/ arcade game is the perfect destination for your next getaway.