Most homeowners choose standard window sizes when they have to install new windows or replace their existing ones. They’re easy to find and often more affordable than custom-made windows. Most top quality window brands offer standard sizes for different types of windows. In this article, we’ll review the standard sizes for the most common window types below and share our recommendations for professional installation companies.

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What Is a Standard Window Size?

Standard window sizes are the measurements of common window openings. Though you can choose custom windows, selecting standard window sizes will make for a quicker and cheaper installation process because you won’t have to wait for the window to be built, and your contractor likely won’t have to do additional prep work.

If you’re wondering how much professional window services cost, we’ve provided the typical price points for replacements, repairs, and window cleanings below.

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What Home Window Size Do I Need?

The size of your window depends on which type you’re installing. Each window type comes in a few standard sizes. Below are the most common types of windows and their standard heights and widths. We’ve also included each window size notation, which is the four-digit number that’s used to identify your specific window size when ordering. 

Awning Windows

Awning windows open outward and upward. They’re commonly used in bathrooms and kitchens over sinks or countertops. Awning windows come in the following standard sizes:

• 2 feet, 5 inches wide by 1 foot, 8 inches high (2518)
• 2 feet, 9 inches wide by 1 foot, 7 inches high (2917)
• 3 feet, 7 inches wide by 7 foot, 8 inches high (3778)
• 4 feet wide by 1 foot high (4010)

Bay Windows

Because bay windows—sometimes called bow windows—are angled, their sizing isn’t as standardized as other types. However, they typically fall between the following ranges:

• 3 feet, 6 inches to 10 feet, 6 inches wide
• 3 feet to 6 feet, 6 inches high

Casement Windows

Casement windows are common in bathrooms and kitchens. This is because they open outward to the right or left, similar to a door, increasing ventilation. They come in the following standard sizes:

• 1 foot, 7 inches wide by 1 foot, 4 inches high (1714)
• 1 foot, 7 inches wide by 2 feet, 5 inches high (1725)
• 2 feet, 3 inches wide by 2 feet, 3 inches high (2323)
• 2 feet, 9 inches wide by 2 feet, 9 inches high (2929)
• 3 feet, 5 inches wide by 2 feet, 5 inches high (3525)

Picture/Fixed Windows

Picture windows, sometimes called fixed windows, don’t typically open. They’re common in living rooms and kitchens because they increase natural light and provide an outside view. They come in the following standard sizes:

• 3 feet wide by 2 feet high (3020)
• 5 feet wide by 3 feet high (5030)
• 6 feet wide by 4 feet high (6040)
• 4 feet wide by 5 feet high (4050)
• 8 feet wide by 5 feet, 2 inches high (8052)

Single- or Double-Hung Windows

Single- and double-hung windows are the most common window style in homes. Each type has two sashes—the part of the window that holds the glass in the frame. Only one sash opens in single-hung windows, whereas both sashes open in double-hung windows. Here are the standard single- and double-hung window sizes:

• 2 feet wide by 3 feet high (2030)
• 2 feet wide by 4 feet, 4 inches high (2044)
• 2 feet, 8 inches wide by 4 feet high (2840)
• 2 feet, 8 inches wide by 5 feet, 2 inches high (2852)
• 4 feet wide by 6 feet high (4060)

Sliding Windows

Sliding windows open horizontally, except they slide from side to side instead of opening on a hinge. They’re wider than they are tall and come in several standard window measurements, including the following:

• 3 feet wide by 2 feet high (3020)
• 3 feet wide by 3 feet wide (3030)
• 5 feet wide by 3 feet high (5030)
• 6 feet wide by 4 feet high (6040)
• 7 feet wide by 4 feet high (7040)

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Getting a Custom Window Size

If you want a unique design or are replacing windows in a house with uncommon window dimensions, a specialist can take measurements and create the size and shape you want. Be aware that custom windows take longer to order, and the cost to replace these windows is more due to the additional labor to install. Expect to pay roughly 50% more for a custom window. 

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Top 7 Window Installation Companies

Working with a professional window installation company can reduce your chances of making costly mistakes. Below are our picks for the top window installation companies based on 400+ hours of research and interaction with window companies:

Renewal by Andersen: Most Hands-Free Install

Champion Windows: Best Financing and Discounts

Power Home: Most Customizable

Castle Windows: Best Warranty

Milgard Windows: Best Fiberglass Windows

Marvin Windows: Most Innovative Windows

Harvey Windows and Doors: Best Custom Hardware

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Our Conclusion

Buying common window sizes makes window installation and replacement easier and more affordable for homeowners. While some older homes have uncommonly sized windows, most new homes have the standard window sizes listed above. To figure out which size you need, measure your window opening and look for the corresponding size notation online or in-store. We recommend hiring a licensed window specialist to help you determine the best window size for your home improvement project if you have limited DIY window installation experience.

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FAQ About Window Sizes

Are there standard window sizes for replacement windows?

Yes, there are standard sizes for replacement windows. Window manufacturers make various window types in standard sizes, and most new homes have standard-sized window openings. You may have to order custom windows if you live in an older home.

What is the size of a typical bedroom window?

The typical bedroom window is single- or double-hung. Standard single- and double-hung window sizes range from 2 feet by 3 feet to 4 feet by 6 feet.

What are standard sliding window sizes?

Standard sliding window sizes are 3 feet by 2 feet, 3 feet by 3 feet, 5 feet by 3 feet, 6 feet by 4 feet, or 7 feet by 4 feet.

What is a standard window rough opening?

A standard window rough opening is half an inch larger than the actual size of the window. You can add half an inch to the standard window sizes listed in this article to get the rough opening size. 

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