If you are measuring for a new door, replacing an existing one, or checking whether a door opening is standard, width matters more than most people realise.
In the UK, most doors fall into a small number of standard widths. However, the actual opening you need depends on whether the door is internal or external, the frame thickness, and whether the property is modern or older.
This guide explains standard UK door widths clearly, including real world fitting tolerances used by suppliers and installers.
Standard UK Door Widths Explained
The most common standard door widths used in the UK are listed below. These measurements refer to the door leaf only, not the frame or opening.
Common UK Door Widths
| Door Width (mm) | Door Width (inches) | Typical Use |
|---|---|---|
| 686 mm | 27 inches | Narrow internal doors, older homes |
| 726 mm | 28.5 inches | Standard internal doors |
| 762 mm | 30 inches | Widely used internal doors |
| 826 mm | 32.5 inches | Wider internal doors |
| 838 mm | 33 inches | Common external door width |
| 926 mm | 36.5 inches | Wheelchair accessible doors |
In practice, 762 mm and 838 mm are the most common widths encountered in UK housing.
Internal Door Widths in the UK
Most internal doors in UK homes are either 726 mm or 762 mm wide.
- 726 mm is common in older properties and tighter layouts
- 762 mm is now the most widely used internal door width in modern homes
Wider internal doors, such as 826 mm or 926 mm, are typically used where accessibility is required or where the layout allows for it.
External Door Widths in the UK
External doors are usually wider than internal doors.
The most common external door widths are:
- 838 mm for standard front and back doors
- 926 mm for wheelchair accessible entrances
External doors also require space for stronger frames, thresholds, and weather seals, which affects the overall opening size.
Door Width vs Structural Opening
One of the most common mistakes is confusing door width with structural opening size.
The door width is only the leaf. The actual opening in the wall must be larger to allow for:
- The door frame
- Fixing tolerance
- Insulation and sealing
As a general rule:
- Add 70 to 90 mm to the door width for the structural opening
- External doors may require slightly more depending on the frame system
For example, an 838 mm external door often needs an opening of around 910 to 930 mm.
Are UK Door Sizes Always Standard?
No. While many homes use standard sizes, there are exceptions.
You are more likely to encounter non standard widths if:
- The property was built before the 1930s
- The opening has been altered during renovations
- The door frame is unusually thick or decorative
In these cases, doors are often made to size even though they look standard from the outside.
Renovation vs New Build Door Widths
Renovation Projects
When replacing a door in an existing opening, the width is usually dictated by what is already there. This often means working around:
- Brickwork that cannot be easily altered
- Older frames with different proportions
- Slightly uneven openings
New Build Projects
New builds are typically designed around modern standard sizes. This makes it easier to use:
- 762 mm internal doors
- 838 mm external doors
- 926 mm accessible doors where required
Why Width Matters More Than Height
Most UK doors share similar heights, usually around 1981 mm or 2040 mm. Width varies far more and has a bigger impact on:
- Accessibility
- Furniture movement
- Compliance with building regulations
This is why door width is usually the first measurement suppliers check.
Practical Supplier Insight
As a UK window and door supplier, Colin’s Sash Windows sees the same widths repeated across most projects.
The vast majority of UK homes fall into one of three categories:
- 726 mm internal doors
- 762 mm internal doors
- 838 mm external doors
Anything outside this range usually requires additional checking or bespoke sizing.
Quick Summary
- Standard UK door widths range from 686 mm to 926 mm
- 762 mm is the most common internal door width
- 838 mm is the most common external door width
- Structural openings must be larger than the door leaf
- Older homes are more likely to be non standard
Working with Non-Standard Openings?
Even if your opening is not standard, doors can be made to measure. Exact sizing matters far more than standard dimensions for a perfect fit.
Frequently Asked Questions
What is the most common door width in the UK?
762 mm is the most common internal door width, while 838 mm is the most common external door width.
How much bigger should the opening be than the door?
Typically 70 to 90 mm wider than the door leaf to allow for the frame and fitting tolerance.
Are all UK doors a standard size?
No. Older properties and renovated homes often have non standard openings.
Are wider doors required for accessibility?
Yes. Wheelchair accessible doors are typically 926 mm wide.
