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How to Measure for Replacement Windows

If you’re planning a window replacement, make sure you measure (and double measure) your windows. The last thing you want is to order replacement windows and realize they’re too small or too big for your opening. Here, our window experts explain how to measure for replacement windows.

You’ll want to measure your current window’s width and height in three different places – at the top, in the middle, and at the bottom.

  1. Start at the top of your window and use your measuring tape to measure the width of your window, from the surface of one jamb to the surface of the other (not from the trim strips or from the parting beads.
  2. Measure the width twice more, in the middle of your window and at the bottom of your window.
  3. Write down all three measurements and use the smallest one as your official width measurement.

After you measure the width, you’ll want to measure the window height.

  1. With your measuring tape, measure the left side of your window from the high point of the sill (the surface closest to the inside of your window) to the top of the window opening.
  2. Make two more height measurements, in the center of the window and on the right side.
  3. Write all three measurements down and use the smallest one as your official height measurement.

The depth is the last thing you’ll need to measure before you can order your replacement windows.

  1. Use your measuring tape to measure from the inside window trim and the outside blind stop strip. (Don’t worry about pulleys or parting strips when you measure, since these will be removed before your new window installation.)
  2. You can measure your window depth in several different places, but in general, the depth should be at least 3 ¼ inches.
  3. When you have all three measurements (width, height, depth), call our window replacement experts and we’ll help you choose your new windows.

Tools & Materials

  • Measuring Tape
  • Notepad
  • Pen

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