Internal door sizes in England and Wales are usually built around a 1981mm height, with 762mm wide by 35mm thick the familiar 2ft 6in imperial door. Scotland and many newer metric homes use different combinations, so measure the door leaf and frame rather than relying on a room name or a tape measure taken across the architrave.
Common internal door sizes
The following are door-leaf sizes you will commonly see from UK suppliers. Height is listed first, followed by width and then the usual thickness.
| Door leaf | Imperial description | Typical use |
|---|---|---|
| 1981 x 610 x 35mm | 6ft 6in x 2ft | Small rooms and cupboards |
| 1981 x 686 x 35mm | 6ft 6in x 2ft 3in | Secondary rooms and older homes |
| 1981 x 762 x 35mm | 6ft 6in x 2ft 6in | Most common imperial internal size |
| 1981 x 838 x 35mm | 6ft 6in x 2ft 9in | Wider access and some new-build layouts |
| 1981 x 915 x 35mm | 6ft 6in x 3ft | Wide openings and accessible layouts |
| 2040 x 726 x 40mm | Metric Scottish size | Common in metric homes and some new builds |
Availability varies by style and finish. The useful comparison is the manufacturer’s actual millimetre size, not a rounded product name. Our guide to 6 panel internal doors shows why a design may be available in fewer sizes than a plain flush door.
Common Leaf Sizes: Start With the Answer
The table below shows common UK internal door-leaf examples. It is not an exhaustive standard and should not replace the current supplier’s technical sheet.
| Example leaf size | Approximate imperial width | Check before ordering |
|---|---|---|
| 1981 x 610mm | 24 inches wide | Confirm height, thickness, handing and lining compatibility. |
| 1981 x 686mm | 27 inches wide | Confirm the actual clear opening after the lining is fitted. |
| 1981 x 762mm | 30 inches wide | This is a common reference size, but the existing frame may not match it. |
| 1981 x 838mm | 33 inches wide | Check the opening, wall thickness, hinges and delivery route. |
Metric, Scottish, fire-rated, acoustic and accessibility-related doors may use different product families. Confirm the current range with the manufacturer or supplier before publishing a definitive size claim.
Read the Door Measurement Diagram
STRUCTURAL OPENING ┌──────────────────────────────┐ │ lining / frame │ │ ┌──────────────────────┐ │ │ │ door leaf │ │ │ │ │ │ │ └──────────────────────┘ │ │ clear opening │ └──────────────────────────────┘
The door leaf is the moving slab. The lining or frame is the fixed material around it. The structural opening is the opening in the wall that must accommodate the lining, fixing tolerances and any required packers. The clear opening is the usable passage once the door and frame are installed.
These measurements are related but not interchangeable. A replacement leaf may fit the width but still fail because of thickness, hinge positions, rebate direction, frame condition or the available clear opening.
Scotland, Fire and Accessibility Context
Do not assume that a door size used in England or Wales is the correct metric or supplier size for Scotland. Verify the current regional product range and installation requirements.
If fire resistance, acoustic performance or accessibility is required, use current manufacturer documentation and qualified professional advice. Do not infer compliance from the nominal leaf size alone. Any Part M, fire-door or building-regulation statement should be checked against the current official guidance before publication.
Door leaf, lining and opening: three different measurements
The leaf is the slab that swings. The lining or frame is the timber around it. The structural opening is the hole in the wall. None of these is automatically the same width. A nominal 762mm door needs fitting clearance inside its lining, and the lining needs clearance inside the opening for packing, squaring and adjustment.
Do not measure from the outside of the architrave: it includes decorative trim and can hide a narrow or uneven lining. If you are changing only the leaf, match height, width, thickness, hinge positions, swing direction and the lock or latch preparation. If you are changing the lining too, measure the masonry opening and check the wall thickness.
Leaf width versus clear opening
A 762mm leaf does not create a 762mm clear passage. Hinges, stops, rebates, frame thickness and the angle of the open door reduce the usable opening. Check furniture, radiators, skirting, sockets and light switches, and think about whether someone carrying laundry, a buggy or a tray can pass comfortably.
How to measure for a replacement
If the old door is still there
Open the door and measure the leaf itself in millimetres: height from the top edge to the bottom edge, width across the face and thickness at the latch edge. Measure in three places and record the smallest measurement if the door has moved. Note the hinge count and centres, the handle height, the rebate and whether the door is left- or right-handed. A new slab that is 5mm thicker can stop a latch or change the hinge clearance.
If the frame is empty
Measure the opening width at the top, middle and bottom, then the height at both sides and the centre. Check diagonals or use a long level: an opening that is out of square can need a smaller door or a new lining. Measure the wall thickness at several points, including plaster or lining, and allow for the floor finish. A carpet, tile or threshold can change the finished height by more than the fitting tolerance.
Older and altered openings
In a Victorian terrace, the opening may be tall, narrow, uneven or affected by old plaster. A replacement leaf may be trimmed within the manufacturer allowance, or the frame may need to be rebuilt. In a modern extension, a wider leaf may be possible, but skirting, sockets, radiators and furniture still need to work around it.
Do not widen a structural opening without understanding what is above it. Removing a frame can expose damaged masonry or a lintel that needs support. If the work involves a load-bearing wall, fire separation, electrical wiring or a significant alteration to the opening, bring in a suitably qualified professional.
When a complete doorset makes sense
A replacement leaf may suit a sound, square lining that is compatible with the hinges and latch. If the frame is twisted, damaged, out of square or the wrong thickness, a complete lining or doorset may be more practical. Fire, acoustic and accessibility requirements apply to the assembly, so do not mix certified components casually.
Measure the frame rebate, hinge depth and latch position. Check whether a frame kit includes architrave, stops, hinges, handles, screws and packers. Packaged dimensions matter too: a long lining may be difficult to carry through a stair turn even when the finished door is the right size.
Metric, fire and accessible doors
Metric doors are not simply imperial doors with a rounded label. A 2040mm-high leaf needs a frame and head with enough space, and a 40mm leaf may need different hinges and latch furniture. Fire doors are commonly 44mm thick, carry a rating such as FD30 and must be installed with the correct frame, seals, hinges and closer. Never trim a fire door casually; follow the door manufacturer’s instructions.
For new dwellings, access is about effective clear width, not just leaf width. The UK government’s Approved Document M sets out the relevant approach and clear-opening requirements. An 838mm leaf is often selected to achieve a wider clear opening, but the frame, stops, hinges and approach space still matter. The J B Kind size guide is a useful cross-check for common manufacturer ranges.
Match the construction to the use
Hollow-core, solid-core, glazed, fire-rated and acoustic leaves have different limits and hardware requirements. Do not cut, drill or swap components without checking the manufacturer instructions, especially where certification or an escape route matters.
Even when the headline dimensions match, thickness, hinge positions, rebates, lippings and hardware details can differ between manufacturers. Compare the full product drawing with your survey, and follow the stated trimming allowance for that construction.
Keep a complete survey record
Use a steel tape and write down every reading. Do not assume the old door is its original size: it may have been trimmed, swollen or replaced.
Before removing an existing door, photograph the top and bottom edges so the construction and any trimming can be checked later. Keep the survey notes, product number and manufacturer instructions with the project.
Checks before ordering
- Confirm the supplier’s order format: height x width x thickness.
- Check whether the size is a nominal leaf or a complete doorset.
- Verify the hinge, latch, glazing and fire-rating requirements.
- Allow for the floor finish and the direction in which the door opens.
- Order samples or a single door first if the opening is old, uneven or non-standard.
Practical access and maintenance checks
A nominal size does not reveal how much floor area the leaf occupies. Recheck circulation after allowing for furniture, radiators, switches, skirting, architrave and the finished floor.
If a door starts binding, look for movement, damp, settlement, loose hinges or a new floor before removing material from the leaf. Seasonal movement can change the latch alignment, so tighten loose screws and use only a suitable product on hinges before deciding to trim.
If a new frame is part of the job, read our guide to an internal door frame and the practical notes on a door frame kit before you buy the leaf.
Frequently Asked Questions
Q1. What is the most common internal door size in the UK?
The familiar imperial size in England and Wales is 1981 x 762 x 35mm. It is common, not universal, so measure the existing leaf or opening before ordering.
Q2. Are internal door sizes different in Scotland?
Yes. 2040 x 726mm is a common metric combination in Scotland, although other sizes are also found. The actual existing door and frame decide what will fit.
Q3. Can I replace a door leaf without replacing the frame?
Often yes, if the height, width, thickness, hinge positions, handing and latch details match. A survey is sensible when the frame is twisted or damaged.
Q4. What thickness is a standard internal door?
35mm is common for ordinary internal doors. Fire doors are often 44mm, but always use the specified door, frame, hinges and seals as a tested assembly.
Final Thoughts
Use standard internal door sizes as a shortlist, not as a substitute for measuring. The reliable order is: identify the leaf or opening, check the frame and floor, then confirm the manufacturer’s exact dimensions and any fire or access requirement.
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