Across the UK, homes come in all shapes and sizes, so there’s no one-size-fits-all when it comes to replacement windows. Window dimensions often vary depending on the type, style and age of the property.
That’s why professional installation is so important. Fitters will take precise measurements to ensure a perfect fit in your openings. Draughts and leaks can occur otherwise.
Let’s explore some of the most common window sizes in the UK, so you can get an idea of what size windows you’ll need. It’s often useful for getting accurate quotes.
UPVC Windows
UPVC remains one of the most popular choices for its affordability and low maintenance. Here are some average sizes:
- Heights: 600mm, 1050mm, 1200mm, 1350mm, 1500mm
- Widths: 488mm, 630mm, 915mm, 1200mm, 1770mm

Casement Windows
A versatile and widely used style in the UK. Typical sizes are:
- 635 x 890mm
- 736 x 1194mm
- 736 x 1498mm

Tilt and Turn Windows
Ideal for flexibility and easy cleaning, tilt and turn windows tend to follow these sizes:
- Single: 600 x 500mm (min), 1900 x 1300mm (max)
- Double: 600 x 1200mm (min), 1700 x 2400mm (max)
- Triple: 600 x 1600mm (min), 1900 x 3000mm (max)

Room-by-Room Window Guidance
Bathroom – Windows are typically smaller, prioritising privacy with frosted or obscure glazing.
Living Room – Often home to the largest windows, welcoming natural light in spades.
Kitchen – Windows are usually placed higher and they are shorter in length, often above the sink.
Bedroom – Windows in bedrooms can vary greatly, from wide openings for an expanse of light to smaller, cosier windows designs.

Materials & Their Impact on Size
The material you choose can influence available sizes. The three most common window materials are:
UPVC: Follows standardised sizes, making it budget-friendly and easy to install.
Timber: Often custom-made, especially in traditional or listed properties.
Aluminium: Allows for slim frames and large panes, ideal for modern aesthetics and expansive views.

Understanding standard window sizes is a great starting point, but remember, every home is different. At 5 Star, we take accurate, on-site measurements to ensure your new windows fit flawlessly and suit your home’s character.
Thinking about replacing your windows? Let our expert team guide you through every step, from measuring up to final installation.
LOOKING TO REPLACE YOUR WINDOWS?
We have a fantastic range to choose from so whether it’s a modern style or traditional timber effect windows – we are confident that we will have windows to improve any home to give it the finished look with elegance.
LOOKING TO REPLACE YOUR WINDOWS?
We have a fantastic range to choose from so whether it’s a modern style or traditional timber effect windows – we are confident that we will have windows to improve any home to give it the finished look with elegance.
REQUEST YOUR FREE QUOTE
Simply call us on 01562 60800 or fill in your details for your free, no-obligation quotation, and click “Get Quote.”