Metric Data 12 – Standard Door Sizes

Loft Conversions

In this part of our Metric Data series we are looking at standard door sizes.


You could say this post title “Standard Door Sizes” is a little misleading. Technically speaking there are no standard door sizes but rather most common sizes or most popular. Here we are going to look at the different size doors that are used the most.


The building regulations have standard clear width opening sizes for entrance doors in dwellings and buildings other than dwellings. Here we will be looking at doors associated with dwellings predominantly. The building regulations also have standards depending on whether a building is ‘visitable’, ‘adaptable & accessible’ or ‘wheelchair user’ – be sure to familiarise yourself with these different meanings and requirements by reviewing Approved Document Part M.


You can get the cad file with all of the standard sizes by heading over to our shop. 

Standard Door Sizes


Door sizes can be confusing due to the fact many doors are still manufactured in imperial sizes. Although metric sizes are becoming more common, there is often a mix of sizes just to keep us on our toes.


Standard External Door Sizes

External doors usually have a thickness of 44mm.


Standard external door sizes in metric


  • 2000mm x 807mm
  • 2040mm x 926mm
  • 2040mm x 826mm

Standard door sizes ext metric

Standard door sizes ext ele metric

Building regulations state that an entrance door has a minimum clear opening width of 775mm in a visitable dwelling.


Building Regulations diagram – measurement of clear opening


To calculate clear opening, 60mm can be deducted from the door size to take into account hinges, door stop and thickness of the door.


An adaptable and accessible dwelling must have a clear entrance door width of 850mm.

A wheelchair user dwelling must also have a clear entrance door opening width of 850mm.


Standard external door sizes in imperial


  • 1981mm x 838mm (6’6” x 2’9”)
  • 1981mm x 762mm (2’6” x 6’6”)
  • 2032mm x 813mm (6’8” x 2’8”)


Standard door sizes ext imp

Standard door sizes ext imp ele

Standard Internal Door Sizes


Internal door sizes can also vary widely. Generally, internal door thickness tends to be 35mm for a standard door, but can go up to 40mm. Fire doors will be 44mm for a half hour fire rating and 54mm for an hour fire rating. 


Standard internal door sizes in metric

  • 2040mm x 726mm
  • 2040mm x 826mm
  • 2040mm x 926mm
  • 2000mm x 807mm

Standard door sizes int metric

Standard door sizes int metric ele

Standard internal door sizes in feet


  • 1981mm x 686mm (6’6” x 2’3″)
  • 1981mm x 838mm (6’6” x 2’9”)
  • 1981mm x 762mm (2’6” x 6’6”)
  • 2032mm x 813mm (6’8” x 2’8”)

Standard door sizes int imp

Standard door sizes int ele imp

Accessible internal door sizes

The building regulations state that internal doors must have a clear opening width of 750mm as a minimum when approached from a corridor of 900mm from head on. This increased to 775mm clear opening width when approach is not head on, from a corridor of 1050mm. Door width must have a clear opening of 800mm from a 900mm corridor when approach is not head on. This applies to Part M4(1) and M4(2) visitable dwellings and accessible and adaptable dwellings.

Building Regulations table showing clear opening widths of internal doors for accessible dwellings

An 826mm door leaf, up to 44mm thick will be deemed to satisfy the clear opening width requirement of 775mm. 


A wheelchair user dwelling (M4(3)) must have all internal doors clear opening width of 850mm as standard. 

Fire door sizes


All standard door sizes tend to be available as fire doors, with an increased thickness of 44mm or 54mm, for a half hour rating (FD30) or hour rating (FD60) respectively. It is also necessary to ensure your ironmongery, frames, and intumescent seals also adhere to the building regulations for fire doors. 


Other doors


French door sizes

French doors are double leaf doors, that tend to open out, available in both hardwood, softwood and of course UPVC. Typical sizes for french doors include:


French door Metric Sizes

  • 1106mm wide x 1994mm high
  • 1200mm wide x 2100mm high
  • 1500mm wide x 2100mm high
  • 1800mm wide x 2100mm high

Standard french door sizes 1

Standard french door sizes 2

Imperial Sizes

  • 914mm wide x 1981mm high
  • 1168mm wide x 1981mm high



Garage door sizes


Single garage door sizes

  • 1981mm wide 
  • 2134mm wide
  • 2286mm wide
  • 2438mm wide


Double garage door sizes

4267mm wide

Heights of garage doors tend to be 1981mm or 2134mm.



What is the standard door height in the UK?

Most doors in England and Wales tend to be a door height of 1981mm (6’6”). 


Scotland usually uses the metric equivalent at 2040mm.


What is the standard door width in the UK?

The standard width of an internal door in England and Wales is 762mm (2’6”). 


In Scotland the standard tends to be the metric slightly smaller 726mm. 

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