How Do You Measure a Window for Replacement?

Are you thinking about replacing your windows? Upgrading your old, leaky windows to energy-efficient ones is a terrific way to weatherproof your home. And the best part? Daring DIYers can replace them on their own. 

But if you’re about to type ‘how do you measure a window for replacement?’ into your search bar, we’re going to stop you right there. K&J Windows is the leading provider of windows and doors in Phoenix, and our team is revealing exactly how to measure your windows for replacement in today’s blog post. 

Steps to Follow for Window Replacement

So, how do you measure a window for replacement? While the process isn’t very difficult, it does require precision. Here’s how to measure your windows for replacement: 

1. Accuracy is Essential

When recording your measurements, remember that accuracy is key. It doesn’t matter whether you’re replacing a single window or redoing your entire home, it’s important to take your time and measure carefully. 

2. Check for Square

Once you take your first measurement, you’ll know whether the existing window frame is square. Essentially, this means that all four corners of the window are 90°. If the window frame isn’t square, the new window won’t be able to open. 

To check for square, hold the tape measure taut, and measure diagonally from inside the upper left corner to inside the lower right corner. Then, carefully record the measurement. Repeat the process in the other diagonal direction and record that measurement. If the two numbers are within ¼ inch of one another, your window is square. If not, you’re going to want to call an expert. 

3. Measure the Width 

After confirming your window is square, you’ll measure the window’s width. For accurate results, you’ll have to measure the window in three places: the bottom, the middle, and again at the top. 

Position the tape measure against the window jamb on both sides. (The jamb is the vertical board running along the window sash, which is where the window opens and closes.) Then, do the following: 

• Bottom measurement. Slide the window up and measure from jamb to jamb at the lowest point. 
• Middle measurement. Slide the window all the way open and measure from jamb to jamb (aim for as close to the middle as possible). 
• Top measurement. Close the window and measure from jamb to jamb at the highest point. 

Make sure you carefully record each measurement. Then, highlight or circle the shortest one. 

4. Measure Window Height 

Measuring the window’s height is fairly similar to measuring the window’s width. Again, you’ll want to take three measurements: on the left, in the middle, and on the right. Measure from the head jamb (the top) to the bottom sill (which is the horizontal board the bottom of the window rests on). Then, carefully record the measurements. 

Top Window and Door Installer in Phoenix

So, how do you measure a window for replacement? Simply follow the above steps and round your numbers to the nearest ⅛ inch. Then, contact the K&J Windows team to order custom replacement windows for your home.