Window Measurements for Replacement Windows: Here's What to Know

If you aren’t sure how to get proper window measurements for your new windows, or you don’t have much construction experience, it’s a good idea to leave the work up to a professional.

At Glass Doctor®, our certified professionals can take accurate window measurements and install replacement windows quickly and efficiently. Schedule an in-home consultation with us today at 855-603-1919.

What Are Standard Window Measurements?

When you’re thinking about replacing your windows, it’s important to understand the standard size notations that windows are given. This will help you get an idea of what size you want your custom windows to be. A window opening size notation is split into four digits—the first two for width and the second two for height.

These notations are simple to understand once you know what they’re trying to say. For example, a 3638 window opening would measure at 3 feet 6 inches in width, and 3 feet 8 inches for height. Knowing these notations can help you be much more confident when measuring and ordering windows on your own.

For most people, the measuring process is relatively simple. Most windows have standard, consistent dimensions that are designed to fit into the common rough opening sizes in homes. If your home has standard rough openings, you can choose from a variety of common windows that can be put right into those openings.

While these dimensions won’t work for every window replacement, they are designed to fit most homes.

Take a look at two of the most standard window size measurements:

2020 Window

The 2020 window is a common type of window within most standard homes and measures 24 by 24 inches, width by height. There is a half inch taken off of the height and width of the window to ensure proper fit, making it a “2020 window.” These dimensions are common in both new and old homes.

3838 Window

Another common window opening is the 3838 window. This window is given its name because it measures 44 by 44 inches in size, but a half inch is taken off for width and height.

How to Take Window Measurements

Regardless of if you have windows in brick, rock, wood siding or stucco, here’s how to measure the width, height and depth of your current windows:

  • Width—To measure the width, get measurements from the top, middle and bottom of the window opening. Measure from the surface of the jambs, instead of the trim strips or parting beads. Use the smallest of these three measurements when creating a custom window.
  • Height—Measure from the high point of your windowsill to the top of the window opening. Make sure to measure on the left side of the sill, in the center and on the right side of the sill. Use the smallest measurement for your new window to ensure you can get the right fit.
  • Depth—There should be 3 1/4 inches of depth between the inside window trim and the exterior blind stop strip.

Note that 1/2 to 1/4 inch will be subtracted from the width and height to ensure your new window fits properly in the opening.

Custom Window Solutions at Glass Doctor

At Glass Doctor, we offer a variety of custom window solutions that can save on energy costs and increase your home’s overall curb appeal.

Take a look at some of the custom window solutions that we offer:

Install New Windows with Glass Doctor Today

Ensure your replacement windows fit properly by calling Glass Doctor to take accurate window measurements of your existing windows. Schedule an appointment with us today at 855-603-1919.



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