Knowing the size of your current window or patio door can be helpful if you want to replace the entire unit, replace a sash or panel, purchase an insect screen, or potentially get a new product installed. This article is a collection of various size charts to help you understand what type of window or patio door you'd need to replace your product.
How to Determine the Size of Your Window or Patio Door
The best way to determine the size of an Andersen® window or patio door is to measure the unobstructed glass dimensions, or the visible glass surface you can see and touch, and use those measurements to find your window's unique unit sizing code.
If you are interested in swapping window or patio door styles, you will need to know the minimum rough opening dimension, which is the minimum opening that a window unit can be installed into. For more information, see Andersen's Technical Documents. 
This Article Will Help You:
- Determine the size of your window or patio door.
- Order a replacement part.
Let's Get Started
1. Measure the Visible Glass Dimension
To use the size charts below, we recommend you follow the directions in Measure Andersen® Window or Patio Door Glass. After measuring the visible glass of the window or patio door, follow the steps below to find your product's unit sizing code.
2. Determine the Size of Your Window or Patio Door
- Select the correct size chart available at andersenwindows.com based on your window or patio door's product type and product Series.
- After you select the correct size chart, follow steps one (1) through four (4) below if you want help reading the size charts to find your product's unit sizing code.
- If you don't need assistance, see Order a Replacement Part below.
|
Understand Your Product's Unit Sizing Code
- Once you've selected the correct size chart, match the visible glass width you measured to the "unobstructed glass" measurement at the top of the size chart (#1 in the image to the right).
- Then match the length you measured to the "unobstructed glass" measurement on the left-hand side of the size chart (#2 in the image to the right).
- On the size chart, locate the diagram where those two (2) measurements intersect (#3 in the image to the right).
- Write down the series of numbers or letters below the diagram.
|
Example: Visible glass width is 26-5/8 inches, and the length is 23-13/16 inches on an A-Series Casement Window, meaning that the window's code is ACW21028.
|
If the window or patio door measurements do not match the size charts, it could be a custom-sized unit. In this instance Contact Andersen® Windows and Doors for assistance in determining the unit size.
3. Order a Replacement Part
If you prefer ordering a part yourself, you can:
- Search your unit sizing code in the Andersen Parts Store to order a replacement window sash, door panel, or an insect screen.
Additionally, if you'd prefer not to order a part on your own, Contact Andersen® Windows and Doors for assistance.
©2026 Andersen Corporation. All rights reserved.
