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Windows

Standard Window Sizes

On this page:
  • How to measure windows
  • Types of windows and their standard sizes
  • Custom window sizing must-knows

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What is a Standard Window Size?

When you are shopping for new replacement windows, you will probably notice that most of them are available in a few consistent size dimensions. These windows are designed to fit into the most common rough opening sizes in homes. They will not work for every window replacement, but it makes sense for manufacturers to produce windows that will work for most homes. To avoid paying a premium on custom windows, stick to standard window sizes when possible.

What Size Window Do I Need?

Window manufacturers will use a simple size notation for replacement windows to help you identify the size needed for your rough opening. A window’s size notation is basically width and height combined. The first two #’s are for width and the second two #’s are for height.  A 2426 Replacement Window would have a width of 2’4″ and height of 2’6″. The actual measurements of the window are usually 1/2 inch less than the whole number identifier it is labeled as.

For example, a window marked to fit a 44″ x 44″ opening will actually measure around 43 ½” x 43 ½”. That is because the manufacturer adds half an inch to each of the size dimensions so the window can be installed with ease.

The window dimensions you go for will also affect the cost of window installation in your home. Read on to learn about different windows with their standard sizes, models and their average cost by top window brands.

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Sizes for Popular Window Types

Regardless of which type of window you select, you need to know how to measure a window. Another handy tip to know? The most common window size across the country is two feet by three feet.

Double-Hung Window Sizes

Line of three double-hung windows as seen on a home's exterior

Double-hung windows are the most common type of replacement window in the United States. They come in a wide range of sizes to fit any rough opening.

  • Double-hung widths: 24″ min  to 48″ max
  • Double-hung heights: 36″ min to 72″ max

Double-Hung Window Size Chart

Below, you’ll find a size chart for double-hung windows detailing the rough openings of the widths and heights.

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Check out our guide to double-hung window sizes to learn more as well as to view a size chart.

Picture Window Sizes

picture window in bedroom

Picture windows are designed for architectural appeal and for allowing more light into a home. Here are the ranges for widths and heights”

  • Picture window width:  24″ min to 96″ max
  • Picture window height: 12″ min to 96″ max

The largest picture windows are around 8 feet x 10 feet (96 inches x 120 inches).

Picture Window Sizes Chart

The size chart below shows the rough opening heights and widths for picture windows. You can use it to help you get an idea for the general size and shape of the window as well as for finding specific model numbers of picture windows.

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Read our guide to picture window sizes to learn more.

Sliding Window Sizes

sliding window above a bathtub

Sliding windows are usually wider than they are tall, but they also come in other shapes and sizes. Here’s the typical range of widths and heights offered standard:

  • Sliding window width:  36″ min to 84″ max
  • Sliding window height: 24″ min to 60″ max

Sliding Window Size Chart

You can explore all the standard sizes of a sliding window in our size chart below. Be aware that, like for other window types on this page, these sizes show the rough opening height and width for your window. We also show the model number these windows are known by.

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You can see all the standard sizes for sliding windows as well as explore the most popular sizes for homes at our guide to sliding window sizes.

Bay Window Sizes

bay window in a living room

Bay windows can help enhance any room in your home, but it is a major (and costly) project. These are the standard size ranges you can expect to come standard from manufacturers:

  • Bay window width: 3’6”min to 10’6” max
  • Bay window height: From 3’ min to 6’6” max.

Many homeowners find that their window is three to six feet wide and also three to six feet tall. The standard depth a bay window extends (so from the wall out to the furthest point of the window) is 18 to 24 inches.

To explore just how large these windows can get or how small you can find one in a standard size, check out our guide to bay window sizes.

Casement Window Sizes

Modern living room with black casement windows

Hinged windows that open from the side also known as replacement casement windows.

Casement window sizes have a fairly wide range of sizes that come standard: 

  • Casement width: ranges from 1’ 2” to 2’ 11.5”
  • Casement height: ranges from 2’ 5.5” to 6’ 5.5”

Typically, a casement window for homes will start at 2 feet (24 inches) and increase in 2-inch increments. The height starts around 4 feet (48 inches) and increases in 6-inch increments.

You can read our complete guide to casement window sizes to find the right fit for your own home.

Awning Window Sizes

Large awning windows on the exterior of a home

Awning windows are popular in rainy regions since they are hinged at the top and open up, creating a natural awning that lets you leave the window open even in inclement weather. Here are the standard sizes they come in:

  • Awning window widths: 2′ min to 3’10 1/8″ max
  • Awning window heights: 1’8” min to 7’8 7/8″ max

Though they can come in larger sizes, awning windows tend to be one of the smaller (and thus cheaper) window types. The typical range homeowners choose from is two to three-and-a-half feet wide and one-and-a-half to three feet tall.

You can explore all there is to know in our guide to awning window sizes.

Custom Size Windows

If you can not locate standard sized windows to fit into the rough openings of your home, you have two options. The first is to adjust the size of your rough opening to accommodate a standard window. This is often the best option if the adjustments aren’t difficult.

The second is to order custom windows through a supplier like Lowes, Home Depot, or a local window company. You will give your window measurements to an associate and decide what frame material and glass you want for your specific window type. The supplier will help you figure out which companies can complete the order for you. You will then select the company, pay for the windows and wait for your order to be filled.

After the order is in, you will wait several weeks for the windows to be manufactured and shipped. You can either have the windows delivered to your home or go and pick them up. You will be responsible for finding a local window contractor to install them for you unless it was included in your purchase agreement. The cost of installing new windows will vary by the size and replacement window types you choose.

big living room window

Older homes are especially well known for needing custom sized windows. This is because they were built before windows were being produced in mass quantities, so their windows often have odd dimensions that don’t fit standard window sizes. Dealing with custom windows is more time consuming, and there are more decisions to be made. You will also spend a great deal more money than you would with standard windows. But the benefit is that custom windows are tailored specifically for your home.

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Frequently Asked Questions

What size is a standard bedroom window size?

A standard window size for a bedroom window depends what type of window you have installed or are needing replaced in your bedroom. Most homes are fitted with single hung or double hung bedroom windows. If this is the case, it’s quite likely your bedroom windows are one of the following sizes:



  • 24 in. x 36 in.

  • 24 in. x 46 in.

  • 28 in. x 54 in.

  • 28 in. x 66 in.

  • 28 in. x 70 in.

  • 34 in. x 46 in.

  • 34 in. x 62 in.


The cost of a replacement window will vary greatly based on your bedroom window’s size. if you don’t know what to expect for window installation prices, it may be smart to use a windows cost calculator to get a local price estimate on a particular window type with a specific window frame material in order to prepare for your replacement window project and budget accordingly – even if it is a DIY project.


How do I know what window size I need?

When shopping for new home windows, window manufacturers and contractors will use a simple size notation for replacement windows to help you identify the size needed for your rough opening.


A window’s size notation is basically width and height combined. The first two #’s are for width and the second two #’s are for height.



  • A 2426 replacement window would have a width of 2’4″ and a height of 2’6″. The actual measurements of the window are usually 1/2 inch less than the whole number identifier it is labeled as.


Measuring windows for accurate sizing can often get confusing if you have not done so before. A window contractor near you will be more than willing to come out to your home and give you the most accurate cost estimate for each window size that you need.


Are replacement windows sized the same as new construction windows?

As new construction windows are designed to be installed into brand new homes</strong, they are a “different size” than your standard sized replacement window. Be sure to know the difference on these before purchasing new windows, especially if you are planning to install the window yourself and are not familiar with the process.


Replacement windows can easily be placed in an existing location and sized for where your old windows were installed. New construction windows will have new nailing attachments or attached flanges or fins that are best suited for new home window openings. You will be able to find more standard window sizes for other window types above as well as the ability to get in touch with local contractors to help you size and replace your windows without the hassle.