686mm internal doors (78" x 27")
686mm is the second most common internal door width in the UK, quoted in the trade as 78" x 27". It is the standard fit for bathrooms, en-suites, box rooms and cupboards — openings where 762mm would eat wall space that a room this size cannot spare.
If you are measuring a UK house built any time in the last century, most bedroom and reception doors will be 762mm and the bathroom will be 686mm. That pattern is so consistent it is worth checking before you measure anything.
The number that matters for using the room, though, is not the width of the leaf.
Showing all 5 doors
Prices are guide prices including VAT, taken from the smallest size and plainest finish of each door. They are not an offer to sell — confirm the price for your size and finish before ordering.
White Flush Internal Door
A plain flat door with nothing to catch dust or argue with the architecture — the honest choice for a modern house, a utility room, or anywhere the door is not the point.
- Primed MDF
- 35mm
Guide price from£38.40inc VAT11 sizesWhite Primed Shaker Door
Clean two-panel shaker lines in a white primed finish — the most forgiving door in a mixed-age house, and the cheapest way to make a landing look deliberate.
- Primed MDF
- 35mm
Guide price from£50.40inc VAT11 sizesOak 4-Panel Internal Door
A traditional four-panel oak door with raised mouldings — the default choice for Victorian and Edwardian houses, and the one most people picture when they say "oak door".
- Engineered oak
- 35mm
Guide price from£106.80inc VAT11 sizesOak Glazed 3-Light Door
Three glazed lights in an oak frame — for borrowing daylight from a hallway into a room that has none of its own.
- Engineered oak
- 35mm
Guide price from£150inc VAT7 sizesOak Cottage Ledged Door
Vertical boards with ledges across the back — a genuine cottage door for period properties, where a moulded panel door would look wrong.
- Solid oak
- 35mm
Guide price from£198inc VAT4 sizes
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Clear opening width, not leaf width
A 686mm door does not give you a 686mm opening. The frame takes some, the door stop takes some, and the open leaf itself stands in the way of a little more. The usable gap — the clear opening width — is always meaningfully less than the leaf.
This matters if anyone needs to get a wheelchair, a walking frame or a hospital bed through. Approved Document M sets clear opening widths for dwellings, and they are expressed against corridor width rather than as one number. [VERIFY: Approved Document M, current edition] — check the figure that applies before committing to a width for an accessible route.
Where 686mm belongs
- Bathrooms and en-suites, where the door swing is already tight against a basin or a bath.
- Box rooms and single bedrooms, where a wider opening takes wall you need for furniture.
- Cupboards and airing cupboards.
- Older cottages and terraces with narrow original openings.
If your opening is between sizes
Openings in old houses are rarely a standard size. If yours falls between 686mm and 762mm, buy the 762mm door and trim it down rather than buying the 686mm and packing the frame out. Trimming is a controlled operation with a limit set by the manufacturer; packing a frame out by 40mm each side is joinery you will be looking at every day.
Take the allowance seriously. Most manufacturers permit only a few millimetres per edge, and taking more than that off a door can void its guarantee. The allowance is stated in the instructions supplied with the specific door.