If you're considering installing shutters, one of the most important first steps is getting accurate window measurements. Whether you're ordering custom-made shutters or buying standard sizes, precise measurements ensure a perfect fit and a polished finish.
This guide walks you through how to measure your window shutters, whether you’re planning an inside mount or outside mount installation.
Tools You’ll Need
Steel measuring tape (for accuracy)
Pencil and notepad
Step stool or ladder (if needed)
Level (optional, for checking frame straightness)
Step 1: Decide on Your Mount Type
There are two common mounting styles:
Inside Mount
Shutters fit inside the window recess or opening
Ideal for clean, built-in looks
Requires a deep enough window frame
Outside Mount
Shutters are mounted outside the window recess, overlapping the wall or trim
Good for shallow or uneven window recesses
Often used to make windows appear larger
Knowing your mount type determines where and how you measure.
Step 2: Measure for Inside Mount Shutters
Measure the width and height inside the window recess. Take three measurements for each to account for any variation.
Width:
Measure top, middle, and bottom of the opening
Record the narrowest width
Height:
Measure left, center, and right sides
Record the shortest height
Note: Use the smallest measurements to ensure the shutters fit snugly inside the opening without forcing or bending.
Step 3: Measure for Outside Mount Shutters
For outside mounts, measure beyond the window opening to allow for full coverage.
Width:
Measure the width of the window opening
Add at least 2 to 3 inches on each side (total of 4 to 6 inches)
Height:
Measure the height of the window opening
Add 2 to 3 inches at the top and bottom
This ensures proper overlap and full light control.
Step 4: Check Window Depth (Inside Mount Only)
If you’re planning an inside mount, measure the depth of your window recess. This will confirm whether there’s enough space for the shutter frame and louvers to operate without obstruction.
Minimum depth recommendations:
Standard louvers (2.5 inches): approx. 2 inches minimum
Larger louvers (3.5 to 4.5 inches): may require 3+ inches depth
If your window frame is too shallow, consider an outside mount.
Step 5: Double-Check Your Measurements
Before placing your order, recheck each measurement:
Make sure you’re using inches or millimeters consistently
Confirm mount type and louver size with your supplier
Round down to the nearest 1/8 inch if required
Common Measuring Mistakes to Avoid
Measuring only once
Assuming all windows are the same size
Not accounting for window handles, cranks, or tilts
Forgetting to check for frame warping or depth issues
Conclusion
Measuring your windows accurately is essential to getting a clean, custom fit for your new shutters. Whether you’re going for a sleek inside mount or a bold outside frame, following these steps will ensure your shutters look professional and perform beautifully.
Need help? Many shutter companies offer free measurement services or consultation—don’t hesitate to take advantage of expert advice.