20% Off Your Installed Project This July. Plus, $0 Down, 0% Interest, 0 Payments for 12 Months*

A man uses a tape measure to determine the width of a window.

How to Measure for Replacement Windows + Patio Doors

Measuring your windows is a good first step toward replacing your windows. Having the measurements ahead of time can make your search go quicker. You can also learn more about the condition of your windows and whether they remain plumb and true. When you work with Marvin Replacement a project manager will measure your doors and windows. We then verify the measurements before sending the replacement window or patio door order to our manufacturing facility.  

Measure Windows Yourself or Hire a Pro? 

Measuring your windows doesn’t take a lot of DIY home improvement skills. While you can easily measure windows, it’s a good idea to have a professional measure them before you begin a replacement project. Our project managers accurately measure and record the dimensions of your windows so they’ll fit perfectly when we install them. We verify the height, width, and depth of each window before sending your order to manufacturing.  

When you schedule a free design consultation with a Marvin Replacement consultant, they will inspect your windows to determine their condition. Our design consultants also explore all the available options for your home and answer all your questions.  

Tools You’ll Need 

  • Tape measure 

  • Pen or pencil 

  • Measurement form 

  • Ladder 

Project time: Less than two hours, about five minutes per window 

Window Terms to Know 

Sash: The operating and/or stationary portion of the window that holds the glass and is separate from the frame. 

Head jamb: The horizontal piece forming the top of the frame on a window or door. 

Sill: The lower, horizontal piece of a window or exterior door frame that supports the frame. 

Jamb: A jamb is the vertical side of a window frame.  

How to Measure for Window Replacement 

Window and door measurements are always recorded width first and then height.  

1. Measure Window Width 

For windows, measure the inside of one jamb to the other with a tape measure. The jamb is the vertical piece of trim on each side of a window. If your window doesn’t have a jamb, measure from each end of drywall. Record the measurement.  

Do not include the trim in your measurement. It’s a good idea to take three measurements and use the shortest measurement. Measure twice, cut once, right? 

2. Measure Window Height 

For windows, measure from the sill to the head jamb with a tape measure. If your window doesn’t have a head jamb, measure from the sill to the drywall. Write down the measurement. Take three measurements in three different locations to ensure accuracy. Use the shortest measurement.  

3. Measure Window Depth 

You don’t need to measure depth because a Marvin Replacement consultant will verify your measurements during your appointment. Window depth is tougher to measure because windows might not rest exactly at 90°.  

How to Measure Patio Doors 

Measuring patio doors takes just a few steps.  

1. Measure Patio Door Width 

For patio doors, measure from the inside of one jamb to the other with a tape measure from inside your home. Record the measurement.  

2. Measure Patio Door Height 

For patio doors, measure from the threshold, to the head jamb with a tape measure from inside your home.  

What to Do with Measurements 

Once you’ve recorded your measurements, schedule an appointment with a Marvin Replacement expert to discuss options in a no-pressure, hassle-free in-person or virtual consultation.  

When you move forward with your project, a measure technician will verify all window and door measurements before placing your order. If you’ve got Special Shape windows, we can help measure those for you. 

Back to All Articles