What Are the Standard Window Sizes in the UK?

Most manufacturers do offer standard window sizes in the UK, although some houses may have bespoke sizes or shapes. If you are replacing your windows, it’s essential to get the right measurements for the windows before you can start to look at the window sizes.

As measurements need to be perfect, it is always better for an installer to measure for you to get the right window size. An the end of this article, we explain how to measure your windows.

The Standard House Window Sizes in the UK

Standard sizes vary between different styles of windows, so please refer to the tables below.

Standard uPVC Window Sizes

The most popular material for windows in the UK, uPVC windows offer a versatile frame and a variety of size options.

Average uPVC window height:

Average uPVC window width:

Standard Casement Window Sizes

Casement windows are the most popular style of window in the UK and they are the most versatile window, available in many different configurations. So, the industry doesn’t specify a standard size.

Despite this, many manufacturers do offer a range of sizes for casement windows.

The most common standard sizes for single casement windows:

Everest manufacture made-to-measure casement windows to order so that your window installation is the perfect fit.

Standard Sash Window Sizes

Sliding sash windows are a classic style of window, most often found on period properties.

Most period sash windows were built during the Victorian and Edwardian periods. At that time, the standard width for sash windows was approximately 1.2 m (4 feet). So most period sash windows fit this size.

Sash window standard widths:

     Sash window standard heights:

Sash window sizes can vary widely, especially for any windows built before and during the Georgian era. If your property has a non-standard size window, you will require bespoke size frames to be made.

Everest, supply and install made-to-measure sash windows with timber or uPVC frames.

The Size of Windows in Different Rooms

Generally, rooms in the home will have windows of different sizes because the light and ventilation requirements are not the same in every room. Plus, you might have smaller windows in a bathroom, for example, to maintain privacy levels.

Bathroom windows

Your bathroom windows will most likely be the smallest windows in the house. The standard size for them will depend on which type of window they are (casement, sliding sash, etc.).

Living Room Windows

Living rooms tend to have the largest windows in the home. The lounge is one of the most frequently used rooms and often the focal point of the property, it's important for the windows to look good and allow in plenty of light. Sliding sash, bay and casement windows are commonly used for living rooms.

Kitchen Windows

The height of windows in a kitchen will differ depending on where they are located. For example, windows located above the sink are calculated by considering the height of your kitchen cabinets and the thickness of the countertop. Any windows that are fitted above a backsplash will need to consider the height of the backsplash.

Bedroom Windows

In the past 20 years, larger bedroom windows have increased in popularity.

Standard bedroom window sizes:

How to Measure Windows

Always measure your windows from the outside. Use a good metal tape measure and hold it taut and make sure it’s vertical or horizontal point to point across the frame or window aperture.

Take three measurements, one in the middle and two towards the edges. Use the smallest measurement. Repeat this for the height and width.

Also, measure your windows from corner to corner to make sure they are square.

Check your measurements several times. You do not want to get these wrong.

A window needs some tolerance when it’s fitted so manufacturers will deduct between 5-10mm from measurements to make an allowance.