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Size Conversion Guide

There are many different standard door sizes available in the UK and making sense of them all can be confusing. We hope using the information on this page will help enable you to choose the most suitable door sizes for your project.

Standard door sizes in the UK can be divided into two main categories, Imperial or Metric. A typical ‘Imperial’ door size used in residential properties is 30x78 inches and often in the industry we refer to this imperial standard using millimetres 762x1981. For newer buildings it is becoming increasingly popular to use ‘Metric’ standards where door widths increase in 100mm increments i.e. 626, 726, 826 x 2040 high, a list of these standards are listed below.

At Doorsan we custom make every interior door to order, meaning you are not restricted by the standards shown below and each door can be created to any size that you desire, please click here to view some of our interior door designs and finishes.

Size Conversion

Quickly turn millimeters to inches and vice versa, using our online measurment convertor.

STANDARD INTERIOR NON FIRE RATED DOORS (NFR)

INCHESSTANDARD IMPERIAL DOOR SIZES (in millimetres)
12x78 (1 3/8" thick)306x1981x35
15x78 (1 3/8" thick)381x1981x35
18x78 (1 3/8" thick)457x1981x35
21x78 (1 3/8" thick)533x1981x35
24x78 (1 3/8" thick)610x1981x35
27x78 (1 3/8" thick)686x1981x35
30x78 (1 3/8" thick)762x1981x35
32x80 (1 3/8" thick)813x2032x35
33x78 (1 3/8" thick)838x1981x35
 
INCHESSTANDARD METRIC DOOR SIZES (in millimetres)
20 45/64" x 80 1/4" (1 37/64" thick)526x2040x40
24 5/8" x 80 1/4" (1 37/64" thick)626x2040x40
28 5/8" x 80 1/4" (1 37/64" thick)726x2040x40
32 1/2" x 80 1/4" (1 37/64" thick)826x2040x40
36 7/15" x 80 1/4" (1 37/64" thick)926x2040x40
 
CODECUSTOM DOOR SIZES
C35Any door size up to a maximum of 915x2135x35
C35XLAny door size up to a maximum of 1220x2440x35
C40Any door size up to a maximum of 915x2135x40
C40XLAny door size up to a maximum of 1220x2440x40

FIRE RATED INTERIOR DOORS (FD30)

INCHESFD30 RATED IMPERIAL FIRE DOOR SIZES (in millimetres)
12x78 (1 47/64" thick)306x1981x44
15x78 (1 47/64" thick)381x1981x44
18x78 (1 47/64" thick)457x1981x44
21x78 (1 47/64" thick)533x1981x44
24x78 (1 47/64" thick)610x1981x44
27x78 (1 47/64" thick)686x1981x44
30x78 (1 47/64" thick)762x1981x44
32x80 (1 47/64" thick)813x2032x44
33x78 (1 47/64" thick)838x1981x44
 
INCHESFD30 RATED METRIC FIRE DOOR SIZES (in millimetres)
20 45/64" x 80 1/4" (1 47/64" thick)526x2040x44
24 5/8" x 80 1/4" (1 47/64" thick)626x2040x44
28 5/8" x 80 1/4" (1 47/64" thick)726x2040x44
32 1/2" x 80 1/4" (1 47/64" thick)826x2040x44
36 7/15" x 80 1/4" (1 47/64" thick)926x2040x44
 
CODEFD30 RATED CUSTOM FIRE DOOR SIZES
C44Any door size up to a maximum of 915x2135x44
C44XLAny door size up to a maximum of 1220x2440x44

Conventional parts of the door