Door sizes are one of the few places where building convention is genuinely settled: two families of numbers cover most of the world, and everything in a builder's merchant is made to them. What trips people up is not the numbers — it is which number a drawing states. A floor plan dimensions the structural opening; a door catalogue sells the leaf; a wheelchair or a sofa needs the clear width. This page gives all three, in both unit systems, and every figure is the one Gridsnap actually draws with.
The chart: standard door sizes by room
| Where | Metric opening | US / imperial | Why |
|---|---|---|---|
| Entrance door | 900–1000 mm | 36″ | Wide enough for furniture, a pushchair, a fridge. |
| Habitable room (bedroom, living, kitchen) | 900 mm | 32–36″ | The everyday internal door. Gridsnap draws 900 mm (36″ imperial) by default. |
| Bathroom, WC, store room, sauna | 800 mm | 28–30″ | Smaller by convention — nothing large has to be carried through. |
| Double / French door | 1500–1800 mm | 5'–6' | Two leaves meeting in the middle. Defaults: 1800 mm, or 6'-0" imperial. |
| Garage door | 2400 mm | 8'-0″ | A single overhead sectional. Doubles run to 4800–5000 mm. |
Heights barely vary: 2100 mm across metric countries, 6'-8″ in North America, for every door in the house. A taller door — 2400 mm, 8'-0″ — is a design decision that commits you to matching frames and usually a taller storey, which is why it stays rare.
Opening, leaf, clear width — three different numbers
This distinction is the single most useful thing on this page. The opening is the hole in the wall, and it is what a plan dimensions. The frame is built into that hole — in Gridsnap's drawing, a 30 mm post on each side. The leaf hangs between the posts, and the clear width is what remains once the leaf is open past the door stop.
Worked through: a 900 mm opening − two 30 mm posts = an 840 mm leaf, and about 820 mm clear at the door stop. An 800 mm opening leaves roughly 740 mm clear — which is why a bathroom that has to take a wheelchair gets a 900 mm opening, not an 800 with good intentions. Design to the clear width whenever the question is "will it fit through".
The exact numbers Gridsnap draws with
In metric mode a new door is the European standard; switch the drawing to feet-inches and new doors are the US standard — real imperial sizes, not conversions of the metric ones. Every value is editable per door afterwards, from 300 mm up to a 6 m sliding glass wall.
| Dimension | Metric default | Imperial default |
|---|---|---|
| Opening width | 900 mm | 36″ (914 mm) |
| Opening height | 2100 mm | 6'-8″ (2032 mm) |
| Leaf thickness | 40 mm | 1¾″ (44 mm) |
| Double door width | 1800 mm | 6'-0″ (1829 mm) |
| Garage door width | 2400 mm | 8'-0″ (2438 mm) |
| Frame (jamb) depth across the wall | 92 mm | — |
| Frame post along the wall | 30 mm | — |
Nine kinds of door, one size logic
The widths above apply whatever the door does — what changes between variants is the space the door needs around the opening. A hinged leaf reserves a quarter-circle of floor; a sliding door reserves wall beside the opening instead; a pocket door disappears into the wall and needs a clear stud bay at least as long as the leaf, with no sockets or pipes in it; a bifold folds back against one jamb; a double-acting door swings both ways and reserves floor on both sides. A cased opening is the same hole with no door in it at all.
A 900 mm pocket door in a small bathroom buys back most of a square metre of swing space — the classic reason to reach for one. How each of these is drawn, with the convention and the CAD rendering side by side, is the door symbols guide.
Leave enough wall beside the opening
The one door-size rule Gridsnap enforces is not about the door — it is about the wall next to it. An opening that leaves between 5 and 50 mm of wall beside it gets flagged by the plan check, because a strip that thin cannot take the frame and its architrave. Hanging a door hard against a return wall is ordinary practice and stays silent; a 30 mm sliver of wall between the frame and the corner is a drafting accident that becomes a site problem.
What no size chart tells you
- Standards are conventions, not law. Nothing stops a 500 mm bedroom door existing; it is just a door nobody can carry a mattress through. Gridsnap draws any width you type and does not pretend to enforce a minimum.
- Accessibility is a legal requirement with local numbers. Clear widths, approach space at the latch side, thresholds — set nationally, checked by nobody's drawing software, including this one.
- Fire ratings, acoustics and door sets are product properties, not geometry. A plan records where the door is and how big; the specification says what it is made of.
Frequently asked questions
What is the standard door size?
In metric countries the standard internal door opening is 900 mm wide by 2100 mm high, with 800 mm used for bathrooms, WCs and store rooms. In the US the standard is 36 inches wide by 6 feet 8 inches high (roughly 914 × 2032 mm), with 28–30 inch doors common for bathrooms. Both are the opening in the wall, not the leaf that swings in it.
What is the standard door height?
Two conventions cover most of the world: 2100 mm in metric countries and 6'-8" (2032 mm) in North America. Taller doors — 2400 mm, or 8'-0" — are an architectural choice, not a standard, and they cost you a matching taller frame and usually a taller wall.
What size should a bathroom door be?
Convention is one step down from the habitable rooms: 800 mm where bedrooms get 900, or 28–30 inches where bedrooms get 32–36. The reasoning is simply that nothing large has to be carried through. If a wheelchair has to pass, go the other way — draw the bathroom door at 900 mm, because an 800 mm opening leaves only about 740 mm clear once the frame is in it.
What is the difference between the opening size and the door size?
The opening is the hole in the wall; the leaf is the panel that swings in it; the clear width is what is left between the frame posts. A 900 mm opening with a 30 mm frame post each side leaves an 840 mm leaf and about 820 mm of clear passage at the door stop. Floor plans dimension the opening — but wheelchairs, sofas and appliances care about the clear width.
How wide is a double or French door?
Two leaves sharing one opening, typically 1500–1800 mm in metric or 5 to 6 feet in imperial. Each leaf ends up around 750–900 mm — ordinary single-door territory — which is why a double door feels generous without needing special hardware.
What size door do I need for wheelchair access?
Accessibility rules are set nationally, but most of them want at least 800 mm of clear passage — and clear is the operative word. Because the frame eats about 80 mm of the opening, an 800 mm opening does not give an 800 mm passage; a 900 mm opening does, with a little to spare. When in doubt, draw 900 mm and check your local requirement, because no drawing tool checks it for you.