Your internal doors can make a huge difference to your interiors. They can help you to keep your living space insulated, block out unwelcome noise and enhance the aesthetic of your interior design concept. Whatever your style of property and wherever your tastes lie, we carry internal doors in a huge range of materials, styles and finishes. So you can achieve the perfect aesthetic for your home. 

But how do you know which sized door you need?

You may assume that all internal doors are the same size. But blind-buying an internal door without considering the size could lead to frustration, not to mention furious planing and chiselling. Here, we’ll look at common internal door sizes and how to size your internal doors to ensure the perfect fit.

How are internal doors measured?

When measuring your interior doors, you need to focus on the following measurements:

• Height
• Width
• Thickness 

It’s best to measure the inside of the door frame rather than the door leaf itself. When measuring width, go from left to right at the top, middle and bottom. Whichever one of these measurements is the largest will be the door width you require. The same goes for thickness. When measuring height, measure from the left, the right and the middle. Whichever of these is the largest will be the height you require. 

What is the standard internal door size?

If you are replacing your doors for the first time, you may wonder if internal door sizes standard? While there is no single standard size for internal doors, nor is there a specific building code stating what size a door should be, internal door sizes do tend to fall within a certain range. 

For instance, the most common internal door dimensions are 1981 x 762 x 35mm. This is commonly known as a 2’ by 6’ door because the dimensions are approximately 6 by 2 feet in imperial measurements. 

Average door height in the UK

The average height of an internal door in England and Wales is 1981mm (6 feet 5 inches). Doors in Scotland, however, are a little taller on average at 2040mm (6 feet 8 inches).

Average door width in the UK

On average, an internal door in England and Wales is around wide 762mm (2 feet 6 inches). Doors in Scotland are a little narrower at 726mm (2 feet 4 and a halved inches).

Standard door sizes Metric vs Imperial

While the above represent the average internal door dimensions, internal doors in the UK generally fall within a fairly standard size range. As such, most of the internal doors you’ll find on our site fall within the size range below:

• 1981mm x 306mm ( 6′ 6″ x 1′ 0)
• 1981mm x 381mm (6′ 6″ x 1′ 3)
• 1981mm x 457mm ( 6′ 6” x 1′ 6”)
• 1981mm x 533mm (6′ 6” x 1′ 9”)
• 1981mm x 610mm (6′ 6” x 2′ 0″)
•  1981mm x 686mm (6′ 6” x 2′ 3”)
• 1981mm x 762mm (6′ 6” x 2′ 6”)
• 1981mm x 838mm (6′ 6” x 2′ 9”)
• 2032mm x 813mm (6′8″ x 2′8″)
• 2040mm x 526mm (6′8 1⁄4″ x 1′8 5⁄8″)
• 2040mm x 626mm (6′8 1⁄4″ x 2′0 5⁄8″ )
• 2040mm x 726mm ( 6′8 1⁄4″ x 2′4 5⁄8″)
• 2040mm x 826mm (6′8 1⁄4″ x 2′8 5⁄8″)
• 2040mm x 926mm |(6′8 1⁄4″ x 3′0 5⁄8″)
• 2085mm x 865mm (6’10” x 2’10”)
• 2134mm x 915mm (7′0″ x 3′0″)

Door thickness is usually either 35 or 40mm unless the door is a fire door. It’s important to remember that even doors that are a perfect fit may need to be planed slightly to fit the unique contours of your door frame. As such, internal doors have a few centimetres of lipping that enables you to trim the door to size without exposing the core. 

Other internal door sizes

As we can see, there’s a substantial margin when it comes to standard Internal doors, with most ranging anywhere between 1981 x 457 x 35mm and 2040 x 926 x 40mm. However, door sizes may sometimes fall outside of this range, especially in older properties or properties with unconventional dimensions. 

For instance, where limited wall space means that a smaller door is required, the most common size is 1981 x 610 x 35mm or 1981 x 686 x 35mm. 

When a door requires wheelchair access, 1981 x 838 x 35mm is the most common size to allow clearance. Homes for wheelchair users must have a clear entrance door opening width of at least 850mm. This calculated by deducting 60mm from the door size to account for the door’s thickness as well as doorstops and hinges.

UK Fire door standard sizes

Fire doors are thicker than standard internal doors. While most internal doors are either 35mm or 40mm thick, internal fire doors are 44mm thick. They must also be used in an appropriate fire door frame to accommodate this thickness. Fire doors require 3 hinges rather than 2, and must be equipped with intumescent strips, smoke seals or both to prevent heat and smoke from escaping between the door leaf and frame. 

Fire doors typically range from 1981 x 686 x 44mm and 2032 x 813 x 44mm. 

What if I don’t have a standard size internal door frame?

If your door frame does not fall within the common internal door sizes mentioned above, don’t worry. We also offer bespoke doors made to your specification that will guarantee a perfect fit once hung. Talk to our experienced and knowledgeable team to request an estimate for this service. 

Find the perfect internal doors for your home

Whatever the dimensions of your door frames and the demands of your decor, we have the doors to match. We’re proud to stock a huge range of doors from the UK’s most trusted manufacturers in a great range of styles, finishes, colours and sizes. Whether you’re looking for the timeless simplicity of a traditional shaker door or something more ornate, we can help you find the perfect fit for your home.