To determine the size of window you will need, follow these simple steps:

Determine whether or not you are simply replacing the operating portion or the entire window unit including the frame. If you are replacing the entire window, including frame and trim, follow our new construction full frame window measuring guidelines

If you are replacing only the operating portion of the window and leaving the jambs and trim intact, refer to the replacement window measuring guidelines below.

Some common measuring techniques are illustrated in the figure below and may not apply to all
manufacturers. Be sure to refer to the manufacturer’s instructions to ensure properly sized windows.

As always, if you are unsure or uncomfortable, stop into your local Curtis Lumber and let our friendly and knowledgeable salespeople walk you through the process.

When measuring for a replacement window, you are trying to determine the size of the pocket in which to fit the new window. The window pocket is the area inside the jambs where the new window will be installed.