When considering fitting new doors and door frames, getting the sizes right is crucial.

While there is a standard door frame size in the UK, there are also doors that come in a range of shapes and sizes. So, you’re going to need different door frame sizes to accommodate them.

With that in mind, let’s take a closer look at the most common options.

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What are door frames?

Door frames are technically used alongside external doors, whilst casings and linings are the terms used for the frames around internal doors. That being said, often the phrase ‘door frame’ is used interchangeably.

External door frame vs internal door lining diagram.

Either way, door frames are the key component from which a door is hung. Fitted within the doorway and, they have a practical use but also help to enhance the aesthetic appeal of the door by creating the finishing touches to the room and the door.

So, finding the correct size door frame is crucial.

The question is:

What are standard door frame sizes, and how do you find the right UK  door frame size for your project?

What are the standard door frame sizes?

Unfortunately, there is no hard and fast rule on standard door frame sizes in the UK. The most common door frame width is 762mm/30″, as they can accommodate the most regularly sized door.

However, the door frame size you require depends on the wall opening. Bear in mind that this can vary from building to building, meaning there are different options. The best way to find out the size of the frame you require is to ask your builder or fitter about the opening size.


If you already have a door that you are replacing, a simple way to find out the rough opening size is to measure the existing door, then add 2″/51mm to the width of the door, and 2.5″/63.5mm to the height of the door. For example, if your door is a standard 24″/610mm wide and 78″/1981mm high, the rough opening size would be 26″/660.5mm by 80.5″/2045mm

Door lining

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Universal door frames

Don’t worry if you’re having trouble working out what size door frame you need – there’re a simple solution! You can purchase universal door frames, which will accommodate any single door size typically up to 36″/914.4mm by 84″/2133.6mm. A range of door sizes can be used in conjunction with the universal frame because the height and width are adjustable.

What’s more, universal frames can accommodate both inward and outward opening doors – simply yours in reverse if needed.

We offer frames to fit both internal doors and external doors. Once you’ve chosen the most suitable frame for your project, take a look at our guide on how to paint a door frame to ensure you create the perfect finish.

Open wooden front door.

If you have any questions or queries on door frames, doors or anything else, feel free to call our team on 01752 422 501 or use the live chat and they will be more than happy to help.

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