When buying windows, it's critical to measure accurately to ensure a good fit.
Methods for Measuring Windows
Determining the process depends on whether you're installing windows on a new home or replacing existing windows.
How to Measure for Windows on a New Home
Measure the size of the rough opening (inside the wood framing). Subtract a ½ inch from the height and width. Choose your profile system, layout and opening of your windows, colors and material to customize how you want your windows to look.
How to Measure for Replacement Windows
Take the existing molding off to view the framing. Measure the width from the inside jamb left to right, then the height from top to bottom. Measure in two or three different places. Take the smallest measurements and subtract a ½ inch from both width and height.