2021 Guide to Standard Window Sizes

Whether you are looking for new windows or a window replacement, understanding a few things about the most common types of windows will certainly help you to make an educated decision.


Whether you are looking for new windows or a window replacement, understanding a few things about the most common types of windows will certainly help you to make an educated decision. The more common windows are usually available in standard window sizes.

The rule is that the 4 numbers on the package of common window types always determine the certain required dimensionsWindow manufacturers use this easy dimension notation to help you figure out the size needed for your rough opening. The initial two numbers show the width of the window, the last 2 are the window’s height. For example:

If the window has the numbers 3020, that indicates this window is 3 feet (36 inches/ 91.5 cm) wide as well as 2 feet (24 inches/ 61 centimeters) high.

However, if you have to purchase a window that is 46 inches wide and 92 inches high, you will want to choose the one labeled 3178. In this case, you will have to convert inches to feet. 

Most often, the dimensions of your living room window will not vary much. However, the measurements of the bathroom, kitchen, and basement windows will depend upon the size of these spaces. For that reason, I will give you some basic options to make the process of picking out your home windows much simpler.

2021 Guide To Standard Window Sizes

Double Hung Window Sizes

Double-hung windows are one of the most common types of window replacements in the United States. They are available in a vast array of sizes to fit most openings. Double-hung windows are simpler to clean, give more airflow, are safer, and come in a tilt design that makes them easier to be cleaned from the inside. They are used in the kitchen, bedroom, hallways, and all around the house. Double-hung window widths can vary from 24 to 48 inches. A double-hung window’s height can be anywhere from 36 to 72 inches.

Picture Window Sizes

Picture windows are designed for their architectural appeal and for letting more light into your home. Most picture windows don’t open, so they can be created in a variety of sizes that can be used in the kitchen, living room, and more. If you’re thinking of purchasing picture windows, you will have a lot of choices from small to large ones. If you have an opening that fits one of these window dimensions listed below, you can probably install a picture window without having to custom order it.

The most standard widths for picture windows are 2ft, 3ft, 4ft, 6ft, and 8ft. Typical picture window heights can vary from 1 foot to as up to 8ft.

Sliding Window Sizes

Sliding windows are usually installed in a bedroom, kitchen, basement, bathroom, or various other places in your home. Slider windows are generally wider than they are tall. If your window measurements fit into the range below, you will be able to install a standard sliding glass window and also have one replaced without needing any special customizations done to the rough opening.

The sliding window widths are 36in, 48in, 60in, 72in, as well as 84 inches. Sliding window heights start from 24in, 36in, 48in, and can go up to 60 inches high.

Bay Window Standard Sizes

Bay windows open up space in your home, they add architectural detail and let in lots more light than your standard windows ever could. Having at least one bay window in a room can enhance the space and add a little charm. It’s a significant improvement to any kind of house and it’s worth the investment for the right space.

Standard bay windows widths vary from 3ft 6inches to 10ft 6 inches. Bay window heights range from 3 ft to 6 ft 6inches high. If you were searching for something bigger, you would certainly want to check out custom dimensions for bay windows which can be an additional expense and reach up to around $650 per window.

Casement Window Sizes

Hinged windows that open up from the right and left sides are better known as casement windows. They’re good for homes in warm locations that rely on the breeze for airflow and comfort throughout the year and make great replacement windows in a pinch. They’re more useful for ventilation purposes than double or single hung windows and they’re also similar in cost. 

Casement window widths range from 1ft 2 inches to 2 feet 11 1/2 inch in size. Their height ranges from 2ft 5.5 inches to a maximum of 6 ft 5.5 inches tall.

Awning Window Sizes

Awning windows are hinged at the top of the window opening and open outward, allowing for plenty of ventilationAwning windows are usually used with other home windows and are simple to open up and close. They can even be opened during light rain and are considered weatherproof.

Common awning window sizes can have a width from 2ft to 3ft 10inches. The standard heights are typically 1ft 8inches to 7 feet 8 inches high.

Custom Size Windows

If you can not find standard-sized home windows to fit in the rough opening sizes of your home, you have two choices for window installation. The first is to change the size of your rough opening to fit the standard home window. This is frequently the best choice if the changes aren’t difficult to make.

The second is to purchase custom windows through a distributor like Home Depot, Lowes, or a local window company. You’ll need to give your window dimensions to an associate and then choose what window frame material and glass you would like for your specific window. The distributor will help you identify which companies can complete the order for you. You’ll then want to select the company, pay for the windows and wait for your order to be completed.

After the order is placed, you’ll have to wait a couple of weeks for the windows to be made and delivered. You can either have the home windows delivered to your house or you can go pick them up. You’ll have to then find a local window specialist to install them for you unless this was included in your purchase contract.

Older houses are well known for needing customized windows. This is because they were constructed before windows were being made in mass quantities, so these windows often have odd measurements that don’t fit standard window dimensions.

Dealing with customized windows is more time-consuming and there are extra decisions you’ll need to make with them. You’ll also invest a lot more money than you would need to with standard windows. However, the benefit of custom windows is that they are tailored particularly to your home.

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Maya Bauer
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