A quick search for a standard sliding door size returns the same handful of numbers everywhere: 60 by 80 inches, 72 by 80, 96 by 80. They feel like answers. They are not the dimension that goes on a purchase order. The gap between a catalogue callout in feet and a factory that builds in millimetres is where most ordering mistakes are born. This article walks through what those numbers actually mean, where they disagree, and how an aluminium sliding door from a metric manufacturer is really dimensioned.
There is no mystery in the arithmetic: one inch is exactly 25.4 millimetres. The trouble starts when a buyer treats a converted value as if it were a catalogue number. Sixty inches converts to 1524 millimetres, but a metric catalogue does not stock 1524; it walks on 100-millimetre or 300-millimetre modules such as 1500. An opening planned against 1524 will not match a frame planned against 1500, and the 24-millimetre difference is exactly the kind of error that shows up as a 1.5-centimetre gap at the reveal.
So the real question is not "what is the standard size in feet". It is "whose module does my opening follow, and what number goes on the order". When you buy from a metric manufacturer such as ALPES, the answer is the millimetre frame dimension, not the imperial name.
The word "size" is doing four different jobs in any sliding door conversation. Mixing them up is the single most common cause of a wrong order.
| Which "size" | What it measures | Who owns it | Goes on the PO |
|---|---|---|---|
| Nominal callout | The marketing name, e.g. "6068" or "six foot by six foot eight" | Catalogue and sales | No |
| Actual frame dimension | The outside dimension of the assembled unit the factory builds | Manufacturer | Yes (in mm) |
| Rough opening | The hole in the wall; frame plus a shim tolerance of roughly 12 to 15 millimetres | The building, not the door | Measure on site |
| Net passage opening | How wide the moving panel actually clears when slid open | Geometry of the configuration | Confirm from drawing |
Most published sliding door sizes describe the rough opening, not the frame the factory builds. On a two-panel unit the moving panel typically clears about half the glazed width; the rest is the fixed panel plus the interlock overlap. Read the clear opening from the approved drawing, not from the nominal callout.
If you compare common sliding door sizes across three suppliers, you will watch the word "standard" stretch from 60 inches to 192 inches. That spread is the proof that there is no single standard.
| Configuration | glassandoor.com | opensliding.com | signatureglassandwindows.com |
|---|---|---|---|
| Two-panel width | 60 to 72 to 96 in | 60 / 72 / 96 in | 60 / 72 / 96 in |
| Three-panel width | 90 to 108 in | 108 / 144 in | 108 in and up |
| Four-panel width | 120 to 144 in | 144 / 192 in | 144 in and up |
| Standard height | 80 in (also 76, 96) | 80 in (also 82, 96) | 80 in (also 96) |
| Rough opening rule | frame plus a small tolerance | frame + 0.5 to 1 in | frame + 0.5 in each side |
The figures above are third-party catalogue ranges, reproduced only to show that no single "standard" exists. Treat them as market context, not as ALPES dimensions.
Here is the same nominal callout expressed three ways. The "exact millimetre" column is arithmetic. The "nearest metric module" column is what a metric catalogue actually stocks. The difference is the silent error.
| Imperial callout | Exact millimetre | Nearest metric module | Difference |
|---|---|---|---|
| 60 x 80 in | 1524 x 2032 mm | 1500 x 2000 mm | 24 / 32 mm |
| 72 x 80 in | 1829 x 2032 mm | 1800 x 2000 mm | 29 / 32 mm |
| 96 x 80 in | 2438 x 2032 mm | 2400 x 2000 mm | 38 / 32 mm |
| 108 x 80 in | 2743 x 2032 mm | 2700 x 2000 mm | 43 / 32 mm |
| 144 x 80 in | 3658 x 2032 mm | 3600 x 2000 mm | 58 / 32 mm |
The lesson is blunt: the converted millimetre is a measurement, the metric module is a product. They are not interchangeable for an opening. Plan the wall against the frame the factory will actually ship.
ALPES builds sliding doors in millimetres, on the 6060-T66 aluminium system with PA66GF25 thermal breaks. The dimension that most often surprises a buyer is the frame wall width: the depth the assembly occupies inside the wall. That number is a series attribute, and it is not dictated by how many tracks the door has.
| Series | Track configuration | Frame wall width | Glass sash thickness | Max single sash |
|---|---|---|---|---|
| SL112 / 167 | Single or two-track 112 mm; three-track 167 mm | 112 / 167 mm | 43 mm | driving capacity 220 kg |
| SL126 / 182 | Two-track 126 mm; three-track 182 mm | 126 / 182 mm | 55 mm | 2500 x 3000 mm (about 7 m2) |
| SL155 | Four-track 155 mm | 155 mm | 54.5 mm | 2800 x 2600 mm (about 7.5 m2) |
Note the honesty point that trips up contractors: the four-track SL155 is 155 millimetres deep, while the three-track SL126 / 182 is 182 millimetres deep. More tracks does not mean a deeper frame; frame depth is a property of the series, not a function of track count. Plan the wall recess against the specific series, not against the number of tracks.
A size table tells you what has been built. It does not tell you what a given panel can weigh. The practical ceiling on a sliding door is the roller rating, and that rating is per sash and dominated by the glass.
Glass weighs about 2.5 kilograms per square metre for every millimetre of thickness. As a worked example, not a product claim: a 6 millimetre plus 24A plus 6 millimetre insulated unit is roughly 30 kilograms per square metre. An SL155 panel of 2.8 by 2.6 metres is about 7.3 square metres, so the glass alone is about 219 kilograms, sitting within the 400-kilogram twenty-wheel roller rating. The published maximum panel size is always stated against an assumed glass thickness; specify a heavier glass and the maximum panel comes down. "Maximum size" is therefore a load question, not a catalogue question.
The frame wall width is the depth the assembly occupies inside the wall, and it must be reconciled with the wall build-up before the wall is built. Public figures put a 2x4 wall jamb depth at about 115.9 millimetres and a 2x6 wall at about 166.7 millimetres. ALPES lists SL112 at 112 millimetres and SL167 at 167 millimetres, which land near those numbers by coincidence. Coincidence is not equivalence: your wall is probably not the exact stud-plus-sheathing-plus-drywall stack those figures assume, and a metric frame depth is the depth of the product, not the depth of your finished wall. Send the wall layering from outside to inside, not just one depth number.
| If your project is | Choose | Why |
|---|---|---|
| A replacement into an existing 60 x 80 or 72 x 80 opening | Standard frame, ordered to the measured opening | No structural change; fastest and lowest risk |
| A new build where the wall is still undecided | Decide the series first, then the wall | Frame wall width must fit the wall recess; new build is the only stage where you can still choose |
| An opening outside the common modules (odd stonework, old property) | Custom, dimensioned from the actual opening | Forcing a standard size compromises the build |
| Oversized panels beyond the published max sash | Custom with engineered load path | Roller capacity and glass weight, not the size chart, set the limit |
Send this to the factory with every dimension in millimetres. Leave nothing as a foot-and-inch name.
| Field | Fill in (mm) | If left blank |
|---|---|---|
| Frame width | ____ | Factory will assume a standard module and may not fit your wall |
| Frame height | ____ | Header and rough opening cannot be planned |
| Rough opening (add 12 to 15 mm) | ____ | Installer has no shim tolerance |
| Series and track count | ____ | Frame wall width unknown; wall recess cannot be matched |
| Glass configuration | ____ | Max panel size and load rating cannot be confirmed |
| We publish | You must still request | Why the gap exists |
|---|---|---|
| Frame wall width, sash thickness, max sash | Thermal K value for sliding series | Sliding series are not published with a K value; request it per configuration |
| 6060-T66, PA66GF25, ROTO / Winkhaus / CMECH / Wehag hardware | Test reports for your exact configuration | 240-hour salt spray and 5000-newton shear belong to a specific window series and do not transfer to sliding doors |
| Roller capacity (220 kg / 400 kg) | Cycle count and service life | Cycle figures are bench tests, not a service-life guarantee |
| Profile thickness range | Written QC standard for your order | Tolerances are set per order, not per catalogue page |
The most quoted is 72 by 80 inches (six foot by six foot eight), with 60 by 80 and 96 by 80 also common. Treat these as rough-opening names, not frame dimensions.
You can convert, but you should not assume the converted number is a stock size. A 60 by 80 inch opening is 1524 by 2032 millimetres; a metric catalogue stocks 1500 by 2000. Plan against the frame the factory builds.
No. The four-track SL155 is 155 millimetres deep, while the three-track SL126 / 182 is 182 millimetres deep. Frame depth is a series attribute, not a function of track count.
Published maxima are about 2800 by 2600 millimetres for SL155 and 2500 by 3000 millimetres for SL126 / 182, but those are stated against an assumed glass weight. Heavier glass lowers the maximum panel.
The actual frame dimension in millimetres, plus series, track count, glass configuration, and the measured rough opening. Never the nominal callout alone.
The sliding series listed here are not published with a K value. Request it per configuration rather than assuming a figure from a different product line.
