Step 1: Measure the Window Width
Measure the width of each window individually from inside edge to inside edge to the nearest 1/4 inch (not including framing or molding). Take a measurement at the top, middle and bottom of the window. Record the smallest number. If your shutters will be operable (meaning you want them to open and close), subtract 1/2 inch from your width measurement to allow for clearance. Consider the size of the trim around the windows when gathering measurements for your exterior shutters. If you have a large trim (4″+) it could result in your shutters appearing smaller, so you may want to add a few inches to the width/height.
Step 2: Record the Final Shutter Width
If you’ll have two shutters (one on either side of the window), divide your final window width measurement in half to determine the width of each individual shutter. If you are measuring for any windows that only need one shutter, you won’t need to divide.
Step 3: Measure Each Window Height
Measure the height of each window from the inner edge of the bottom sill to the bottom of the lintel (see diagram below). Take a measurement at the left side, middle and right side of the window. Record the smallest measurement. Again, if you intend for your shutters to open and close, subtract 1/4 inch from your final height measurement. And that’s it–you’re done!
Want the full measuring guide + worksheet?
Fixed Mount Measuring Example (Pair of Shutters):
- Kristen is buying fixed mount (non-operable) shutters for a large window that will need a shutter on either side of the window.
- She measures her window width at the top, middle and bottom. The smallest measurement of the three is 24″.
- She then divides this number in half to get the individual shutter width (24 / 2 = 12). Her final shutter width is 12″.
- Next, she measures the height of her window (from sill to lintel) at the left side, middle and right side and the smallest measurement is 36″
- The shutter size she needs to purchase is 12″ x 36″.
Operable Measuring Example (One Shutter):
Gray is buying an operable shutter for a small window that will need just one shutter on one side of the window.
He measures his window width at the top, middle and bottom. The smallest measurement of the three is 18″.
Since this shutter will be operable, he subtracts .5 ” for clearance. So his final shutter width is 17.5″.
Next, he measures the height of his window (from sill to lintel) at the left side, middle and right side and the smallest measurement is 26″. Again, since the shutter will be operable, he subtracts .25″ from the height for clearance. His final shutter height is 25.75″.
The shutter size he needs to purchase in 17.5″ x 25.75″.