How to Measure Windows for Shutters  

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Last updated: April 8, 2023

Window shutters are like vertical blinds; instead of making them from lightweight textures, materials like fiberglass and vinyl shutters are part of the manufacturing process. Shutters are eye-catching, durable, and weather-resistant window covers that fit all windows shapes and sizes. Sadly, there is no shutter guide for the easiest type of window, so you must measure it all from scratch.

However, a window shutter brings an authentic look in different places because of advanced preparation before measuring. Have the measuring materials ready before learning how to measure windows for shutters. Knowing simple mathematics is also crucial for inside mount plantation shutters, an outside mount application, and more.

Table of Contents

About Shutters

Window shutters are two pieces, or one piece you must buy twice that may add a square foot to the house. Different shutters are stationary and functional window treatments as solid colors and decorative shutters. Buying used or new shutters is a preference, and there is no wrong answer.

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Functional shutters swing open and closed. The closed position covers both sides of the wide windows and the wide bottom. Stationary shutters remain unlocked as decorative pieces.

Gorgeous shutter style installation is inside or outside. The inside mount fits inside the window frame for a clean, polished, and minimal finish. Outside mount shutters cover the window and the frame for the illusion of a larger window.

Exterior Shutters

To retrieve the width, first, measure the width of the window opening with measuring tape to get an accurate reading. Use half of your total window width as the width. As windows may not be equal on both sides, get the width of your window from the upper and lower sides.

To retrieve the height, measure the vertical side from the bottom of the shutter to the top. You can afford to subtract two inches from the width without messing up window coverage. Don’t forget to record the height measurement on the left and right sides.

Experts prefer the smallest measurement as the single width, so follow that rule. If you want a larger window, add two inches to the height and mount it on the frame. No two windows are the same size, so measure each and include mesh screens and bars.

Depth determines whether the thickness will fit inside the window or blanket the outside trim. That prevents damage when opening and closing an operable shutter for a perfect fit. For depth, measure the inside edge of your window to the window.

Interior Shutters

Installing indoor shutters uses the same method as outdoor shutters, and accurate measurements are paramount. Use a good tape measure to get the width measurement on the left side and right side of the window. For shutter height, measure the top of the window to the top of the window sill.

Indoor home measurements must account for protrusions near the center of the divider rail like latches, bars, handles, and locks. Wide shutters outside the frame are safe options for interior windows to account for the protrusions. Shutters inside the frame are better for protrusion-free windows.

Depth measurement must exclude the protrusions; it will be a rough measurement. Still, the thickness should be the smallest number to avoid damage while using house shutters. The tape ruler should enter from the outside to the inside.

Specialty Windows

Arch and bay-shaped windows use different window measurements than a standard window type. When in doubt, get an expert to do a professional measurement. There is no free ride, but watch for any additional charge beyond the first measure.

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Bay Window

Three sections with windows that stick outward like a trapezoid are bay windows. The bay is noticeable because the windows split into three distinct cornered sections, enhancing curb appeal. Besides the three window bay, curved bay and box bay are available.

A curved bay is several rectangular windows that curve with no corners. A box bay has three windows that resemble a box without a bottom base. They separate their window by section, and each number of panels needs a separate shutter, so use a steel tape measure for best results.

For shutter width, measure the top of the window frame to the bottom of the window horizontally. The same tape measure should get the height of the shutter through the vertical height of your window. Do the entire process on the inside and outside parts of the window.

Don’t forget the window depth of the perfect square window and rectangle. That represents the shutter’s thickness when looking from its side after you purchase it. Therefore, measure depth from the inside out and be sure the number is small enough to include protrusions.

The good idea is to follow exact measurements for each window, even if different windows require a different shutter frame and shutter panels. A differing shutter size for each window size is more appealing visually than a one-size-fits-most version. Also, measure more than once and drop the largest measurement calculated.

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Arch Windows

Arched single windows need arch shutters to complement them. Because of its rounded top, you will need to measure the highest round top point to the top of the sill for the full height. As a general rule, include the trim as part of the height total.

The center part is the longest measurement and most accurate for arched windows. Should they split between a half-circle and a rectangular section, they become two different windows instead of one arch. Meanwhile, the width of the arch still goes across from left to right.

A precise width of your shutters is near the bottom of the frame. Also, measure near the center and choose the smaller of the two. However, do not include the rounded parts at the top because the measurement will not be accurate.

Add half the trim from left to right as part of the window’s width if it exists.

The depth can come from window curves or straight vertical parts. Pick a round and horizontal section and measure from the outside to the inside.

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