- For shutters that close over the windows, measure the width of the window from left to right; measure from the outside edges of the window frame or trim. Always measure across the window in three places; about 6 inches down from the top edge of the window frame, across the middle, and about 6 inches up from the bottom of the window frame. Take the largest of the three measurements for the width. The width of each shutter needs to be half the size of the window. For example, if your window is 60 inches wide, each shutter would need to be 30 inches wide; this allows the shutters to completely cover the window when closed.
- Measure the height of the window from top to bottom; measure from the top edge of the window frame or trim to the bottom of the window frame. Take three measurements; from top to bottom about 6 inches in from the left side of the window frame, down the middle and about 6 inches in from the right side. Use the largest of the three measurements for the height. Shutters that will close over a window should be the same height as the window frame so when they are closed they will not overlap at either the top or bottom. If there is a window sill, the bottom of the shutters should be even with the top of the sill.
- Write the measurements in inches. Always put the width first and the height last. Measure each window even if they appear to be the same size.
- For decorative shutters that do not open and close, you will need to measure your windows' height, as in Step 2. These shutters, however, can be longer than the window frame if desired. Since they are not closing over your window, they can be any width you like.
- Use a metal tape for accurate measurements. Round each measurement to the nearest 1/8 inch. Round down for the width and round up for the height.