Curtis Lumber - Taking the headache out of Home Improvement

New Construction Full Frame Window Measuring Guide

Measuring for new windows is easy.
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 only replacing the operating portion and leaving the frame and trim intact, follow our replacement window measuring guidelines. If you are replacing the full window unit including the jambs, refer to the full frame 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.

Measuring for a Full Frame Window:

When measuring for a full frame window unit, you are trying to determine the rough opening. The rough opening is the unfinished wall or ceiling opening where a window or door will be installed. It is surrounded by the studs on either side, header to the top, and rough sill to the bottom. It is the framing to which the window will mount.


  1. Remove the inside trim to bring jack studs, header, and rough sill into view.
  2. Measure the width of the opening from jack stud to jack stud and record the measurement.
  3. Measure the height from the bottom of the header to the top of the rough sill and record the measurement.
  4. Measure the depth of the opening and determine if the wall is 4-9/16" or 6-9/16" thick and check off the appropriate box.
  5. Repeat for each window and bring the rough opening measurements into your nearest Curtis Lumber. Our salespeople will then be able to show you the options that are available.


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