How to Understand Window Measurements

Posted On October 14, 2015

If you’ve ever gone to look for windows to purchase and you saw something like a 2020 window or a 3838 window you probably weren’t sure what the windows were talking about. The measurement system used to label windows is actually very simple, and once you understand how the system works you’ll never have to wonder if a window is going to fit or not again.

What the Numbers Mean

When you look at that 3838 window you are actually look at a window meant for a opening that is 3’8″ x 3’8″ in size. The first number is the width of the opening and the second number is the height of the opening. If you took your measurement in inches you simply have to convert the figure to inches. So 3’8″ to inches would be 44″ overall. If your home has an opening about 44″ x 44″ then 3838 windows are exactly what you need to buy.

Account for One Half Inch Removed

Windows come with measurements for the openings they should be put in, not their actual measurements. Because of that you have to account for about half an inch of missing width and length on every window if you want to know exact measurements. For example, a 4034 window would be 4′ x 3’4″ minus one half inch from both measurements. That means the window is actually 47.5″ x 39.5″ overall. The half inch is removed so that the windows will install easily and so they can be leveled to the opening properly.

The next time that you go to the store and you are considering buying some windows you will know exactly what those slightly cryptic measurements mean. It’s amazing how simple they are when you understand the system, and it’s easy to see why it’s used since the system lets all the measurement figures be very small overall.