Learn about standard window sizes before you start your next home improvement project!

Most replacement windows on the market come in standard sizes. The manufacturers produce windows in standard sizes as a convenience for homeowners so they can easily find replacements. However, the windows you might find at a hardware store will not fit every frame. So, what are standard window sizes? It all depends on the type of window you have!

The following guide will explain windows size in general as well as the standard sizes for each type.

A Basic Guide to Window Sizes

Window manufacturers use a simplified window size notation to help homeowners find the perfect replacement. They combine the height and width to create a single number. For example, a 2426 replacement window measures 2’4” in width and 2’6” in height.

The window manufacturer adds half of an inch to the stated window measurements, so a window notation of 4444 measures about 4’3½” x 4’3½”. The extra half-inch makes it easier for installers to install the window and allows room for flashing materials.

You can determine the size of a window by measuring in between two opposing jambs and between the window’s head and sill.

Now that you know how manufacturers size their windows, read on to discover the standard sizes for some of the most popular window types.

Types of Windows and Their Standard Sizes

While every type of window comes in a different size, each style has a standard size measurement. Let’s take a look at the most common types of windows and their respective average sizes.

Double-Hung Window Sizes

Double-hung windows represent one of the most popular types of windows and come in several standard sizes. The standard measurements for double-hung windows range from 24” to 48” in width and 36” to 72” in height.

Sliding Window Sizes

Sliding windows provide an excellent solution for rooms with small rough openings in the exterior walls, like bathrooms, kitchens, and basements. As the name suggests, these windows slide open and closed on a track. They typically measure greater in width than in height. The standard measurements range from 36” to 84” in width and 24” to 60” in height.

Picture Window Sizes

Picture windows work well in rooms with scenic views and plenty of wall space. These windows add touches of architectural appeal and allow a lot of light into your home. Most picture windows do not open, but this aspect allows for a wide range of sizes. Picture windows have a standard width of 2’ to 8’ and a standard height of 1’ to 8’.

Casement Window Sizes

Casement windows open from the side and provide ventilation for rooms like kitchens and bathrooms. Casement window widths range from 1’2” to 2’11.5” with standard heights of 2’5.5” to 6’5.5”.

Bay Window Sizes

Bay windows offer homeowners an appealing architectural style that can raise the value of their houses. These windows provide an increased range of vision, enhance a room’s beauty, and add a little extra space. Bay windows come with a standard width of 3’6” to 10’6” and a standard height of 3’ to 6’6”.

Awning Window Sizes

Awning windows possess hinges at the top so they can open outwards from the bottom. Awning windows enjoy a reputation for versatility in inclement weather conditions. The standard awning window sizes range from a width of 2’ to 3’10” and a height of 1’8” to 7’8”.

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