If you are replacing a door or planning a bit of building work, one of the first things you will need to know is the standard door sizes used in the UK. Getting the size right matters, because a door that is even slightly off can mean trimming, packing out the frame or ordering a made to measure unit at extra cost.
This guide sets out the common dimensions for both internal and external doors in one place, in plain terms, so you can measure up with confidence.
Why door sizes are not always straightforward
Here is the thing that catches people out. The UK uses two systems side by side. Older homes often have doors in imperial sizes (feet and inches), while newer doors are sold in metric (millimetres). To make it more confusing, many metric doors are actually just rounded conversions of the old imperial sizes.
So when you go shopping, you will see both. Knowing the common standard door sizes in each system saves a lot of head scratching, especially in older York properties where nothing is ever quite square.
Standard internal door sizes
Internal doors are the ones between rooms inside your home. The most common standard sizes in the UK are:
- 762mm x 1981mm (30 inches x 78 inches). This is the single most common internal door size in the UK.
- 838mm x 1981mm (33 inches x 78 inches). A wider option, often used for accessibility.
- 686mm x 1981mm (27 inches x 78 inches). A narrower door for smaller openings.
- 610mm x 1981mm (24 inches x 78 inches). Common for cupboards, cloakrooms and small spaces.
- 926mm x 2040mm. A larger metric size found in some newer homes.
The standard thickness for an internal door is usually 35mm, though some heavier or fire rated doors are 44mm.
Standard external door sizes
External doors, your front and back doors, tend to be slightly larger and thicker than internal ones because they take more wear and need better security and weather resistance. Common standard external door sizes include:
- 838mm x 1981mm (33 inches x 78 inches). A very common front door size.
- 762mm x 1981mm (30 inches x 78 inches). Another widespread size.
- 813mm x 2032mm (32 inches x 80 inches). A slightly taller metric option.
- 914mm x 2135mm. A larger size for grander or more accessible entrances.
External doors are typically 44mm thick to handle the extra demands of security and insulation. If you are choosing a new front door, our composite door range comes in these standard sizes as well as made to measure options.
What about French doors and patio doors?
Double and sliding doors work a bit differently, as the overall opening is made up of two or more leaves. Common French door openings range from around 1200mm to 1800mm wide, while sliding and bi-fold doors are typically made to measure to fit your exact opening. If you are opening up the back of the house, our sliding and bi-fold door range is built to suit the space you have.
Measuring for a new door
Before you order anything, measure carefully. A few tips:
- Measure the door itself, not just the frame, if you are replacing a leaf.
- Measure the width in three places (top, middle and bottom) and the height on both sides, then use the smallest reading. Old openings are rarely perfectly square.
- Check the thickness so the new door works with your existing frame and hinges.
- Note the hinge and handle side so the new door opens the right way.
If your measurements do not match a standard size, do not panic. It is very common, particularly in older homes. You can either order a made to measure door or, in some cases, have a standard door trimmed to fit.
When standard sizes will not do
Period properties, extensions and anywhere with an unusual opening often need a bespoke door. This is completely normal and not something to worry about. A made to measure uPVC or composite door will fit properly, seal well and look right, which is worth far more than squeezing a standard size into an awkward gap.
If you are unsure what you need, it is always best to have someone measure up properly before ordering. A survey removes the guesswork and avoids costly mistakes.
FAQs
What is the most common internal door size in the UK?
The most common internal door size is 762mm x 1981mm, which is the metric equivalent of 30 inches by 78 inches. If you are unsure what to buy for a standard home, this is the size most people need.
What is the standard front door size in the UK?
There is no single answer, but 838mm x 1981mm and 762mm x 1981mm are both very common front door sizes. External doors are usually 44mm thick, slightly thicker than internal doors, for better security and insulation.
Are UK doors measured in metric or imperial?
Both are used. Older homes tend to have imperial sizes (feet and inches), while newer doors are sold in metric (millimetres). Many metric sizes are simply rounded conversions of the old imperial ones, which is why you see both when shopping.
Can I get a door made to a non-standard size?
Yes. Made to measure doors are common, especially in older or extended properties where openings are rarely a perfect standard size. A bespoke door fits properly and seals well, which is well worth it compared with forcing a standard size to fit.
Not sure which size or style suits your home? Download our latest brochure to see the full range, or ask us for a free quote and we will measure up for you.