Standard Bay Window Sizes and How to Choose the Right One

Shed some light on the right bay window sizes for your room

A bay window in a red brick house
Photo: Susan Vineyard / iStock / Getty Images Plus / Getty Images
A bay window in a red brick house
Photo: Susan Vineyard / iStock / Getty Images Plus / Getty Images
Highlights
  • The average cost of a bay window is between $950 and $7500.

  • Larger bay windows are ideal for living and dining rooms.

  • Smaller bay windows can be added to kitchens and bedrooms.

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.
Geo Icon

A bay window can be a beautiful and functional addition to your home, giving you space for a cozy reading nook or a light-filled dining area. But how can you know what bay window size is right for your home? Before you start your project, make sure to determine what size will work best so you can begin enjoying your bright, spacious new window.

What Are Standard Bay Window Sizes?

Bay windows are a combination of three windows, one center window running parallel to the wall and two flanking windows set at an angle outward from your home. These windows come in a wide range of sizes, styles, and configurations, so there’s almost no limit to what size your bay window can be. There are, however, a number of standard window sizes that you can purchase already configured, eliminating the need for costly customization.

Bay Window Size by Type

A one-story house with a bay window
Photo: Douglas Keister / Corbis Documentary / Getty Images
Type of windowWidth (in feet)Height (in feet)
Canted bay4 to 83.5 to 6
Box bayUp to 4Up to 4
Circle bay6 to 106 to 8

Canted Bay Window

Canted bay windows are the traditional bay windows you’re probably used to seeing, with three windows making half a hexagon extending outward from the house. Canted bay windows are often used in living and dining rooms on the first floor. They can vary in size but are typically at least 4 feet wide and 3 feet 6 inches high or larger.

Box Bay Window

A box bay window is a popular choice for kitchens or smaller areas. These windows also consist of three windows, but all at right angles to each other, forming a box shape extending out. Box bay windows are smaller than most other bay windows, often smaller than 3 feet 6 inches in both width and height.

Circle Bay Window

Circle bay windows are less common than other types of bay windows and are set at less of an angle, giving them a more rounded shape. These windows are often larger than other styles and can measure anywhere up to 10 feet wide and 8 feet high or more. 

How to Measure the Right Size Bay Window

Bay windows can be a little more complicated to measure than other windows since you’re dealing with not only width and height but also depth and angles. To find the right size bay window, you’ll want to measure the rough window opening’s width and height, allowing for the manufacturer’s required spacing between the window and the rough opening. The window depth will be the measurement from the window opening to the front panel.

The three windows that make up a bay window configuration will likely be two different sizes—a large central window and two smaller windows, one on each side. Measure each window’s width and height for accurate measuring. Most traditional bay windows are set at a 30- or 45-degree angle—you can check this with the manufacturer if you don’t want to bring out the protractor.

Factors That Influence Bay Window Size

A bay window with a seating area and a table
Photo: Ivan Hunter / DigitalVision / Getty Images

Budget

When it comes to bay windows, one of the most important factors is your budget. These windows are pricier than other types of windows, with the cost of a bay window averaging between $950 and $7500. The larger the bay window, the more you can expect to spend. Familiarize yourself with all the benefits and drawbacks of bay windows before investing.

Wall Space

The amount of available space will be a determining factor for the size of your bay window. Larger rooms on the first floor, like living rooms and dining rooms, can accommodate larger bay windows, while rooms with less available wall space, like kitchens or rooms on upper floors, will need smaller bay windows.

Building Codes

Your local building codes may also restrict the size of the bay window you can install, although these regulations usually deal with the allowable depth of bay windows and necessary structural support rather than the width or height. Be sure you are aware of any applicable codes.

Angi Tip

Your region's building codes may require a specific size and number of windows for a certain room. Areas like basements, bathrooms, and kitchens all have window code requirements. Your window pro can walk you through the details and ensure your project is up to code.

Caroline Gilbert
Director, Content & Editorial, Angi

Structural Support

Because bay windows extend out from your home, the wall and window will need additional structural support in order to prevent sagging or damage to your home. Larger bay windows will require more extensive support. You may find that your home can only accommodate a bay window up to a certain size without requiring extensive work to add support.

What To Do If You Have the Wrong Size Bay Window

Choosing the wrong size bay window for your home can drastically increase the cost and time of your window replacement project. You’ll likely have one of a few options, as outlined below:

  • Reframe the window to fit the new size

  • Re-order the correct window size

  • Live with the new size, if it works for your home—this could mean a much smaller or much larger window than you imagined

All of these options will increase the cost of your project, by a few hundred dollars at the minimum. If you want to avoid problems associated with buying the wrong-sized bay window, you may want to hire a local window replacement company to tackle the job. They can help you choose the right size bay window for the available space, your budget, and the structural specifics of your home. Once you have the right size bay window installed, you can start enjoying your home’s bright new feature to the fullest.

Frequently Asked Questions

Because bay windows are a combination of three windows, there are many options for how wide or tall they can be. That said, individual windows come in standard sizes, and you can use those as a guide for the width and height of your bay window.

Typically, a bay window is, at minimum, 42 inches wide. That said, you can always design a custom bay window that is smaller—box bay windows are usually less than three feet in width and are ideal for smaller spaces.

There are many standard window sizes. The most common windows, single or double-hung models, typically range from 2-feet by 3-feet up to 4-feet by 6-feet. Of course, sliding windows will be wider than they are tall, though the standard sizing follows the same measurements.

Need professional help with your project?
Get quotes from top-rated pros.
The homeowners guide to window services
From average costs to expert advice, get all the answers you need to get your job done.
brick two story home with lintel
Apr 23, 2025
Apr 23, 2025
If you’re planning to install a new window or door, you may come across lintels. But what is a lintel? Check out this guide for everything you need to know.
Woman in the living room reading a book and drinking coffee
Apr 23, 2025
Apr 23, 2025
Installing new windows can greatly increase your home’s value. Learn how much new windows can increase home value and whether they’re worth it.
Family happy kitchen food counter
Apr 23, 2025
Apr 23, 2025
There are tons of types of kitchen windows that add charm and functionality to your home. Keep reading for a breakdown of 10 types of kitchen windows.
woman at home looking out the window
Apr 23, 2025
Apr 23, 2025
Windows feeling a bit drafty? You may be starting to wonder, “How long does it take to replace a window?” Check out important time considerations here.
Close-up of a broken window
Apr 23, 2025
Apr 23, 2025
Whether it's cracked, drafty, or just won't open all the way, who do you call to fix a broken window? Let's talk about the best pros for the job and who to call as a backup.
Wooden window with flowers
Apr 23, 2025
Apr 23, 2025
If you’ve been facing storms or humidity recently, it may be time to learn how to repair a rotted window frame to make your windows look brand new.