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Door Size Guide

Our quick & useful size conversion charts below can be used to convert measurements from imperial to metric if necessary. (Please note not all products are available in every size, consult the pricing table below this size conversion guide to see if your chosen door is available in a particular size)

You can be sure there are plenty of options for you here at Leader Doors.

Can't see the size you're looking for? We can offer most of our internal oak and white primed doors in custom-made, bespoke sizes. If you have a bespoke requirement please contact us and we'll be happy to help. For more information on ordering bespoke sized doors please click here.


Door sizes are generally displayed on our website as height x width x thickness, which is usually listed in millimetres followed by inches, but don't fret, if you don't work in millimetres or inches here is a handy conversion chart to help!

Colours in orange are the most popular "standard" door sizes. Other colours are less common door sizes which some suppliers offer with the most popular door designs.


Metric (mm)

Imperial (feet & inches)Imperial (inches)
1981 x 3056ft 6" x 1ft78" x 12"
1981 x 3816ft 6" x 1ft 3"78" x 15"
1981 x 4576ft 6" x 1ft 6"78" x 18"
1981 x 5336ft 6" x 1ft 9"78" x 21"
1981 x 6106ft 6" x 2ft78" x 24"
1981 x 6866ft 6" x 2ft 3"78" x 27"
1981 x 7116ft 6" x 2ft 4"78" x 28"
1981 x 7626ft 6" x 2ft 6"78" x 30"
2032 x 8136ft 8" x 2ft 8"80" x 32"
1981 x 8386ft 6" x 2ft 9"78" x 33"
1981 x 8646ft 6" x 2ft 10"78" x 34"
1981 x 9136ft 6" x 2ft 11.9"78" x 35.9"
2040 x 5266ft 8.3" x 1ft 8.7"80.3" x 20.7"
2040 x 6266ft 8.3" x 2ft 0.6"80.3" x 24.6"
2040 x 7266ft 8.3" x 2ft 4.6"80.3" x 28.6"
2040 x 8266ft 8.3" x 2ft 8.5"80.3" x 32.5"
2040 x 9266ft 8.3" x 3ft 0.5"80.3" x 36.5"

If you don't see your chosen door available as a pair door when browsing our website, don't worry. Most of our standard internal doors can be used as pair doors and you can even purchase a pair maker to add a rebate to your doors ensuring they close just as a pre-rebated pair of doors would.

Which Internal Door Thicknesses Are Available? ▼

Internal Door Thicknesses

Our internal doors are available in a wide-variety of thicknesses, from the standard 35mm internal doors, right up to 54mm FD60 rated fire doors. Thickness is always clearly listed on each products page at the end of the size. For a guideline of interior door thicknesses you can use the following as a general rule of thumb;

  • Internal Doors: 35mm - 40mm thick.
  • Internal Fire Doors: 35mm - 54mm thick.

What’s the Average Height of a UK Internal Door? ▼

England and Wales have a standard internal door height of 1981mm. Scotland’s standard internal door height is slightly taller at around 2040mm

What’s the Average Width of a UK Internal Door? ▼

England and Wales have a standard internal door width of 762mm. Scotland’s standard internal door width is slightly smaller at around 726mm.



Metric (mm)

Imperial (feet & inches)Imperial (inches)
1981 x 6866ft 6" x 2ft 3"78" x 27"
1981 x 7626ft 6" x 2ft 6"78" x 30"
1981 x 8386ft 6" x 2ft 9"78" x 33"
1981 x 9156ft 6" x 3ft78" x 36"
2032 x 8136ft 8" x 2ft 8"80" x 32"
2040 x 7266ft 8.3" x 2ft 4.6"80.3" x 28.6"
2040 x 8266ft 8.3" x 2ft 8.5"80.3" x 32.5"
2040 x 9266ft 8.3" x 3ft 0.5"80.3" x 36.5"
2083 x 8646ft 10" x 2ft 10"82" x 34"
2134 x 9157ft x 3ft84" x 36"

Which External Door Thicknesses Are Available? ▼

External Door Thicknesses

For external doors, you will often find a variety of different thicknesses listed, depending on the product type. Generally most external doors are 44mm - 54mm thick, however they can be up to 70mm when looking at some of the fully double glazed folding patio door sets. As with internal doors, thickness will be listed on each products page at the end of the size. For a guideline of interior door thicknesses you can use the following as a general rule of thumb;

  • External Doors: 44mm - 54mm thick.
  • External Fire Doors: 44mm - 54mm thick.
  • Garage Doors: 44mm thick.
  • French Patio Doors &Folding/Sliding Doors: 44mm - 70mm thick.



Metric (mm)

Imperial (feet & inches)Imperial (inches)
1981 x 9156ft 6" x 3ft78" x 36"
1981 x 10676ft 6" x 3ft 6"78" x 42"
1981 x 11686ft 6" x 3ft 10"78" x 46"
1981 x 12206ft 6" x 4ft78" x 48"
1981 x 13726ft 6" x 4ft 6"78" x 54"
1981 x 15126ft 6" x 4ft 11.5"78" x 59.5"



Metric (mm)

Imperial (feet & inches)Imperial (inches)
1981 x 21346ft 6" x 7ft78" x 84"
2134 x 21347ft x 7ft84" x 84"

Fire Door Standard Sizes ▼

All of our standard UK door sizes are typically available in a fire door equivalent. Fire doors are slightly thicker, however, by around 45mm. The construction of a fire door means that extra components are used in the core of the door to improve its fire rating. Take a look at our guide to fire doors to learn more.

Understanding Door Sizes & Measurements ▼

Door Construction ChartUnderstanding door sizes & measurements

When buying your new doors, it's often a huge surprise to new customers that doors are actually supplied in a massive number of sizes. There are some "Industry standard" sizes which almost all suppliers use, however, from experience, we've learned that especially in the UK market there can be some strange sized doors in some of your houses!

While most door suppliers generally stick to the industry standard, we do have a few suppliers such as XL Joinery, LPD & Deanta who can provide us with bespoke door sizes for most of their door styles and we're able to quote you on an order-by-order basis for this. For more info on bespoke sized doors, please read below.

When purchasing your new doors, the starting point is always to measure the opening that you have to fill (the space where your current door is). Most of our doors can be trimmed/planed down to suit the opening you have, but this threshold for adjusting down your doors differs from manufacturer-to-manufacturer. Please see our help & advice page for the trimming allowances of all of our doors.

When working out which size you will require, it's really important to remember that there needs to be a 2-3mm gap around your door to allow it to open and close, this will also ensure your door doesn't crack/warp during winter months when doors are prone to slight swelling due to the humidity changes. You can bet your bottom dollar that the door frame isn't perfectly true and square - after all, it was built by a person not a computer! We recommend you measure each opening to be as accurate as possible, because when buying multiple doors for one house, the openings can sometimes differ in different areas of the house, dependent on the way the house was built.

Can I just measure the door that I'm replacing?

If you have a door already hanging, which you're looking to replace, then it's often much easier to just measure that door - rather than the opening (Especially if you're a DIY newbie!). We'd recommend you check the door to ensure it fits snug in the frame and doesn't have any issues with rubbing on the frame or gaps around the edges. If you're not 100% satisfied or you're looking to replace your frames as well then just measure opening in the wall.

If you're measuring the opening instead

The opening which you will be fitting the door into will need to be measured if you don't already have a door hanging which can be measured. If it's a new opening, then it may not have a frame fitted, when you come to measure this it is usually known as the "brick-to-brick" opening. If your opening already has a frame fitted in it then your measurement would be "frame-to-frame". Once you have your measurements, you will then be able to work out what size door will fit into the opening. If you're not sure still, then just give our friendly Door Experts in our Customer Services team a call. We'll know what size you need and will even be able to discuss pricing and availability with you on the phone. To speed this up, why not click the LiveChat button in the bottom right hand corner of the screen during office hours.

If you already know, then see below to find our list of popular external and internal door sizes.

Trimming Guidelines For Our Doors ▼

If the closest size door is too small for your frame opening, then you may need to pack out the frame with additional pieces of timber. This will effectively reduce the size of your frame opening and will ensure there are no gaps when it comes to fitting your door.

Alternatively, if the closest sized door available is too big for your frame opening, you will need to trim down the size of the door until it fits. This is a job that any competent joiner (or even yourself if you know how) can do fairly easily.

Of course, when it comes to trimming a door down in size there are some recommended guidelines for how much you can take off before damaging the stability of the door. These guidelines are outlined below;

Engineered timber doors

Deanta: All Deanta doors are specially manufactured with extra thick 18mm solid wood veneers. These doors are fantastic for those customers looking to take off a larger amount, as they allow up to 16mm from each side. This means that you can safely reduce the door by a maximum of 32mm (16mm from each side) on all four sides of the door.

Other Brands: All of our other standard timber doors are manufactured with 10mm solid wood veneers. These doors allow up to a maximum of 8mm from each side. This means you can safely reduce the door by a maximum of 16mm (8mm from each side) on all four sides of the door.

White moulded & primed doors

Leader Doors advise that no more than 6mm be trimmed from each side of any solid white primed or white moulded door. Due to the construction of these engineered doors, if can often mean that they become unstable when reduced by any more than 6mm.

Fire doors

We recommend that under no circumstances should a fire door be altered in size, as this could affect the fire rating of the door and may mean it does not stand up to fire safety regulations. If you require a fire door in a custom size, then please contact us and we will enquire with our suppliers to see if one can be made to suit your needs.

If you are unsure, please contact us before performing any work on your doors and we will be happy to help.

Can't find your size? Go Bespoke! ▼

Custom-built doors - to your own specification

It's really important to remember that not every house is the same, in fact, not even every frame and opening in a house is always the same. In the past, odd sized frames and discrepancies around the house may have been a major headache, often leading to frames and linings being ripped out and opening sizes altered. Thankfully, this is no longer a necessity, due to the wealth of bespoke options available from our suppliers that we can offer you.

If you measure up around the house and find that some of your frames and openings don't quite match up with any of our internal door sizes, then just let us know! We can provide almost all of our internal doors from brands like XL Joinery, LPD Doors & Deanta in custom-built sizes to suit your exact specification. We'll always offer the most cost-effective solution and this means there's no need for the hassle of having to trim your doors and when they arrive they will just snugly-fit within the openings around your home.

With most bespoke enquiries, we'd just need to know your required sizes, specifications and which door style you like. We can then speak directly with the supplier, to aquire availability, pricing & manufacturing lead times. We'll always confirm every detail with you first to ensure everything goes as quickly and smoothly as possible and once your doors are ready for delivery we can book in the delivery to you around your availability.

For further information, please click here - or if you wish to speak with our Door Experts you can do so by calling 01429 241 270.

Bespoke Doors - View Our Size Guide
Our Size Guide - Internal and External Door Size Guide

If you have any questions about any of the above information, or need any help at all with working out what size doors you require, please call our Door Experts on 01429 241 270, or you can speak to us anytime via LiveChat (Bottom right of screen) and email! We'll aim to respond to all emails within 24 hours.

Email customerservices @leaderdoors.co.uk

We always endeavour to respond to every email within 24 hours.