There is no standard window size. It depends on several different factors, such as the placement of the window, the style and age of the home and the homeowner’s personal preferences.
However, there are some common sizes for windows, based on their use and their placement. Although standard window sizes may vary from one area to another, here are a few common dimensions:
Standard vertical sash windows: 24″ x 36″
Standard casement windows: 24″ x 36″
Standard sliding windows: 36″ x 24″
Standard picture windows: 72″ x 48″
These dimensions are solely for reference, as they may vary depending on the region and the window manufacturer. To guarantee that your new window fits perfectly, it’s important not to rely on these general dimensions, but instead to take exact measurements of the existing window.