Internal Door Sizing

One thing that a lot of people don’t realise when they start renovating their homes is that internal doors come in several different sizes. There are “standard" door sizes but you cannot simply walk into a shop and buy a door, you need to know what size of door you are looking for.

What Are The Most Common Internal Door Sizes?

Made to measure internal doors come in a number of different sizes. Small internal doors will typically be 762mm x 1981mm, while large internal doors can be as big as 926mm x 2040mm. There are even narrow door widths that are only 457mm wide, but these are very rare.

The most standard internal door sizes are:

• 457mm x 1981mm
• 533mm x 1981mm
• 610mm x 1981mm
• 686mm x 1981mm
• 762mm x 1981mm
• 864mm x 1981mm
• 8383mm x 1981mm
• 813mm x 2032mm
• 525mm x 2040mm
• 626mm x 2040mm
• 726mm x 2080mm
• 826mm x 2040mm
• 926mm x 2040mm

There are other sizes, and if you live in a period property, or a new property where the architect opted to deviate from the above standards, you may need to get some internal doors made to measure.

The most common interior door size by far, the one that was used by the majority of builders over the last few decades, is 762mm x 1981mm. This equates to a standard internal door width of 2ft 6in and a standard height of 6ft 6in. Other door sizes tend to be used for things like toilets, or walk-in cupboards.

What If The Door Opening is Not A Standard Size?

If you are buying an internal door for an opening that does not match the standard door sizes, you should think carefully about what style you buy. While it is possible to trim a door down to size in most cases, there are some door styles, such as the flush or pressed hardboard type of door, that are difficult to trim. These doors have a hollow core and are filled with a lightweight honeycomb. The outer covering of the door is just 25mm thick, which makes it hard to trim the door down to size. 

Hardwood doors and solid internal doors are easier to work with, and give you more flexibility for planning and trimming the door down.  They also give you more freedom when it comes to deciding where to fit the hardware. With hollow doors, there is a ‘lock block’, a 300mm long block of timber that is fitted on one side of the door. When you are fitting a hollow door, it is important to pay attention to where this block is so that the door is fitted with the hinges on the correct size, and the handle and lock is positioned correctly.

With UPVC doors, you do not really have the option of changing the size. If you want a non-standard width or height door then you will have to order the door made to measure. Make sure that the frame is completely plum and smooth, you have left an allowance for the carpet, and that the measurements are accurate, before you place your order, since there is very little margin for error.