Is The Standard Window Size a Myth?

Learn about the most common window sizes and whether there really is such a thing as a standard window dimension.

Related To:
Farmhouse Kitchen With Apron-Front Sink

Farmhouse Kitchen With Apron-Front Sink

No farmhouse kitchen is complete without an apron-front sink. This white one flows seamlessly with the white cabinetry and light gray countertops and backsplash.

Photo by: Arch-Interiors Design Group. Inc.

Arch-Interiors Design Group. Inc.

When you’re thinking of replacement windows, the first question that probably comes to mind is, what’s the standard window size?

But a quick search on the term gives so many options that it soon becomes apparent that there isn’t one common window size. Windows come in a variety of shapes and sizes, from round windows at the top of a vaulted ceiling, to small windows in bathrooms, to giant picture windows. Even double-hung and casement windows have no standard window dimensions.  

The real answer is, what size are your windows? That should be considered the standard. Fortunately, although windows come in all shapes and sizes, installers know how to properly measure to fit.

To give them a head start (or to allow you to order your own windows), here are some tips for finding your proper replacement window sizes.

Rough Opening

The rough opening is the measurement from the inside of one side of the frame to the inside of the other. Manufacturers start with finding the window size by measuring the rough opening. To do this yourself, measure the top, middle and bottom of the window vertically and note each measurement. Then do the same horizontally.

If the difference in any of the measurements is more than one inch, the installers will use filler strips to level the window properly.

Windows measurements are first given in width, then height.

Take of One-Half Inch

Once you have the rough opening, take 1/2 inch off of each measurement. This allows for flashing to be installed and for the window to be made plumb, or centered.

Double-Hung Window Sizes

Double-hung windows, where both sashes move up and down, are one of the most common window types. These windows start at 24 inches and go up to 28, 32 and 40 inches. Their heights vary from 36 to 72, with heights of 44, 52, 54 and 62. Remember to take 1/2 inch off of each measurement for the correct window size.

Sliding Windows

Sliding windows have fewer size options than double hung: 36, 48, 60, 72 and 84 inches are the horizontal options. Twenty-four, 36, 48 and 60 inches are the vertical possibilities. If you hear an installer refer to a window by “6040,” that would mean a window that is six feet wide by four feet tall.

Even though window sizes are all different, the technique for measuring is the same. Whether you’re ordering your own replacement windows, or discussing options with an installer, knowing how to measure properly puts you a step ahead of the game.

Window Anatomy 01:00

Learn all about the anatomy of the window from top to bottom.
Keep Reading

Next Up

Choosing the Best Type of Window Replacement for Your Home

Determine whether a full or partial window replacement will give you the best return on your investment.

Everything You Need to Know About Window Sills and Trim

Get tips for choosing the right window casing, installing it and maintaining it properly.

How Window Insulation Can Save You Money

Weatherproofing windows yourself can be done quickly and cheaply, but it pays off in cost savings and home comfort.

How to Choose the Best Exterior Window Trim for Your Home

Exterior window trim isn’t just a pretty face. It’s made to cover gaps keep your home sound and free from water, heat and humidity. 

All About the Different Kinds of Windows

From casement to clerestory, windows come in a variety of designs and styles. Here’s what you need to know to choose the right one for your home.

Home Window Repair Is Easy When You Know How

Take the mystery out of home window repair with these expert tips.

Here's What You Need to Know About Stained Glass Windows

Stained-glass windows come in a variety of styles, designs and colors. Get expert tips on designs, patterns and even panels.

Repairing Your Window Screens is Easy and Inexpensive

Get tips and advice for repairing and replacing window screens.

All About the Different Types of Plantation Shutters

Plantation shutters come in vinyl, composite and wood. Which is best for your home?

How to Tell a Single-Hung Window From a Double-Hung

Single-hung and double-hung windows have pros and cons. Here’s how to know which is right for your home.

On TV

Income Property

7:30am | 6:30c

Boomtown Builder

8:30am | 7:30c

Rehab Addict

4:30pm | 3:30c
5pm | 4c
5:30pm | 4:30c
6pm | 5c
6:30pm | 5:30c
7pm | 6c
7:30pm | 6:30c
On Tonight
On Tonight
8pm | 7c
8:30pm | 7:30c
9pm | 8c
9:30pm | 8:30c
10pm | 9c
10:30pm | 9:30c
11pm | 10c
11:30pm | 10:30c
12am | 11c
12:30am | 11:30c
1am | 12c
1:30am | 12:30c
2am | 1c
2:30am | 1:30c
3am | 2c
3:30am | 2:30c

Renovation Realities

4:30am | 3:30c

Get Social With Us

We love to DIY. You love to DIY. Let's get together.

Consult Our A-Z Guide

Everything You Need to Know

Browse a full list of topics found on the site, from accessories to mudrooms to wreaths.  

How-To Advice and Videos

Get video instructions about kitchens, bathrooms, remodeling, flooring, painting and more.

Watch DIY Downloads Now

Watch DIY Network LIVE

Don't miss your favorite shows in real time online.