What Size Shower Door Do I Need? UK Sizing Guide | Elani
An 800mm shower door does not fit an 800mm gap. It fits 740–800mm. The adjustment range explained, with fitting tables for every size.
September 21, 2026
5 minutes
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An 800mm shower door does not fit an 800mm gap. It fits 740–800mm. The adjustment range explained, with fitting tables for every size.
September 21, 2026
An 800mm shower door does not fit an 800mm opening. It fits an opening somewhere between 740mm and 800mm. That band — the adjustment range — is the number that actually decides whether your door fits, and it is the one almost no listing puts in front of you. Ordering to the wrong end of it is the single commonest reason a shower enclosure goes back.
Featuring the Elani enclosure range.
Last updated 21 September 2026 · Elani Journal
A shower door is not a fixed rectangle of glass. It is glass plus a wall profile at each edge, and that profile carries adjustment — typically 60mm across the range. The door slides within its own frame to take up the difference between a wall that is plumb and square and a wall that is neither, which is most walls.
So the "800mm" on the listing is the maximum opening the door will close. It will also close 790mm, 770mm, 750mm and anything down to 740mm. What it will not do is close 820mm.
This is why buying to the widest measurement is the mistake to avoid. It feels like the safe choice. It is the one that does not fit.
Walls are rarely parallel, particularly in older properties. Measure the opening at three heights:
At the top, roughly where the head of the door will sit. At the middle, around chest height. At the bottom, at tray or floor level.
You will usually get three different numbers. Order to the smallest of the three. The adjustment in the profile absorbs the rest — that is exactly what it is there for.
Measure wall to wall on the finished surface. If you are tiling, measure to where the tile will be, not to the bare wall. Fifteen millimetres of tile on each side is 30mm off your opening, and 30mm is half your adjustment gone before you start.
For a three-walled recess, one door closes the opening. These are the fitting ranges:
| Door size | Fits an opening of |
|---|---|
| 700mm | 640 – 700mm |
| 760mm | 700 – 760mm |
| 800mm | 740 – 800mm |
| 900mm | 840 – 900mm |
The Battant pivot door is made at 700, 800 and 900mm. The Pliant bi-fold adds 760mm, which is a genuinely useful size — it covers 700 to 760mm, a band the 700 and 800 doors both miss.
Both are 1850mm tall in 6mm toughened glass, and both are reversible, so the same door suits a left- or right-hand opening.
A corner enclosure needs both walls measured, because you are buying two things: the sliding door for the front, and the side panel that returns to the wall.
| Sliding door | Fits an opening of |
|---|---|
| 1000mm | 940 – 995mm |
| 1200mm | 1135 – 1195mm |
| 1400mm | 1335 – 1395mm |
| 1600mm | 1535 – 1595mm |
| 1700mm | 1635 – 1695mm |
| Side panel | Fits a wall of |
|---|---|
| 760mm | 730 – 760mm |
| 800mm | 770 – 800mm |
| 900mm | 870 – 900mm |
On the Coulisse all three side panel widths are the same price, so choose the one that suits your tray rather than the one that sounds cheapest.
A quadrant curves between two walls, so both need to fall inside range:
| Enclosure size | Fits a corner measuring |
|---|---|
| 800 x 800mm | 770 – 795mm on each wall |
| 900 x 900mm | 870 – 900mm on each wall |
| 1000 x 800mm | 970 – 1000mm x 770 – 800mm |
| 1200 x 800mm | 1170 – 1200mm x 770 – 800mm |
| 1200 x 900mm | 1170 – 1200mm x 870 – 900mm |
One extra check on a quadrant that catches people out: it needs a matching quadrant tray of the same radius, not a rectangular one. Both 500mm and 550mm radii are common in UK bathrooms and they are not interchangeable. Check the radius as well as the dimensions.
The Arc is offered square at 800 x 800 and 900 x 900, or offset where one wall runs longer than the other.
A fixed panel is the exception. There is no door and no adjustment band to work within: the width you order is the width of glass you get.
The Voile comes at 800, 900, 1000, 1200 and 1400mm, at 1950mm tall in 8mm glass. Because it is fixed rather than hung, you are choosing how much of the opening to screen rather than how much to close — a different decision, and a more forgiving one.
Then the adjustment cannot absorb it, and no size in the range will sit true. This is uncommon but it does happen, usually in older properties or where a stud wall has bowed.
The options are to pack and re-skim the wall to bring it closer to square, or to move to a format with more tolerance — a walk-in panel, which is fixed at one edge only, is far less sensitive to an out-of-square opening than a door that has to close against one.
If your three figures are that far apart, ask before ordering rather than after.
Shower doors are a standard height and it is easy to assume it does not matter. It usually does not — but check two things.
Doors and enclosures are around 1850mm tall, slightly shorter than a standard internal doorway and roughly three-quarters of the way up a 2400mm ceiling. That leaves about 550mm of wall above the frame, which matters if you are tiling to a line, or if a sloping ceiling comes down over the shower.
Fixed walk-in panels run taller — 1950mm on the Voile — which is a deliberate choice rather than an accident. The extra 100mm carries the glass past standard door height, and that vertical line is what makes a small bathroom read as taller rather than tighter.
An 800mm door. It fits an opening from 740mm to 800mm, so 750mm sits comfortably inside its range. A 700mm door only reaches 700mm and would leave a 50mm gap you cannot close.
The smallest, always. The adjustment in the wall profile takes up the difference between the smallest and the largest. Ordering to the widest measurement is the commonest sizing mistake and produces a door that will not fit at the tightest point of the opening.
It is the band of opening widths a single door size will close — typically 60mm across the Elani range. An 800mm door covers 740 to 800mm. It exists because almost no bathroom wall is truly plumb or square, and the profile absorbs that without packing or silicone.
Measure to the finished surface — where the tile will be, not the bare wall. If you have not tiled yet, subtract the tile plus adhesive from each side. At around 15mm a side that is 30mm off your opening, which is half the available adjustment.
On the Elani recess doors, yes — the Battant and the Pliant are both reversible, so the same door suits a left- or right-hand opening and the handing is decided at installation rather than at checkout. The Coulisse sliding track reverses in the same way.
That is what the adjustment is for, and 60mm covers the out-of-square found in the large majority of UK bathrooms, including older properties. Measure at three heights — if those figures differ by more than 60mm, the wall needs attention before an enclosure goes on it.
Still choosing a format? Read Sliding, Pivot, Bi-Fold Or Quadrant? Working out a budget? See How Much Does A Shower Enclosure Cost?
