Door sizes
16 standard door sizes with the three measurements that matter: the leaf, the hole it needs, and the gap you can walk through.
The door is not the hole
Three numbers describe every doorway and only one of them is the door.
- Leaf — the door itself. This is what you order.
- Rough opening — the hole framed in the wall, about 50 mm wider on each side to take the frame and enough slack to plumb it square.
- Clear width — what is actually left when the door is open, roughly 45 mm less than the leaf, because the stop and the leaf thickness stay in the way.
Ordering a door against the rough opening gets one about 100 mm too wide; specifying accessibility against the leaf width overstates the opening by about 45 mm. Both are common and both are expensive.
British "metric" doors are inches
The standard British internal door is 762 × 1981 mm, which looks like an arbitrary metric figure and is not one: 762 mm is exactly 30 inches and 1981 mm is exactly 78 — 2′ 6″ by 6′ 6″. The whole imperial range was converted after metrication rather than redesigned, which is why every number in it is odd.
The genuinely metric British range is separate and taller — 626, 726, 826 and 926 mm wide at 2040 mm rather than 1981. That is 59 mm of difference, and it is the reason a replacement door bought on width alone so often turns out to be the wrong height.
British sizes
| Door | Leaf | Imperial | Rough opening | Clear width |
|---|---|---|---|---|
| 457 × 1981 mm | 457 × 1981 mm | 1′ 6″ × 6′ 6″ | 557 × 2041 mm | 412 mm |
| 533 × 1981 mm | 533 × 1981 mm | 1′ 9″ × 6′ 6″ | 633 × 2041 mm | 488 mm |
| 610 × 1981 mm | 610 × 1981 mm | 2′ 0″ × 6′ 6″ | 710 × 2041 mm | 565 mm |
| 686 × 1981 mm | 686 × 1981 mm | 2′ 3″ × 6′ 6″ | 786 × 2041 mm | 641 mm |
| 762 × 1981 mm | 762 × 1981 mm | 2′ 6″ × 6′ 6″ | 862 × 2041 mm | 717 mm |
| 838 × 1981 mm | 838 × 1981 mm | 2′ 9″ × 6′ 6″ | 938 × 2041 mm | 793 mm |
| 914 × 1981 mm | 914 × 1981 mm | 3′ 0″ × 6′ 6″ | 1014 × 2041 mm | 869 mm |
| 626 × 2040 mm | 626 × 2040 mm | 2′ 1″ × 6′ 8″ | 726 × 2100 mm | 581 mm |
| 726 × 2040 mm | 726 × 2040 mm | 2′ 5″ × 6′ 8″ | 826 × 2100 mm | 681 mm |
| 826 × 2040 mm | 826 × 2040 mm | 2′ 9″ × 6′ 8″ | 926 × 2100 mm | 781 mm |
| 926 × 2040 mm | 926 × 2040 mm | 3′ 0″ × 6′ 8″ | 1026 × 2100 mm | 881 mm |
American sizes
American interior doors are 80 inches tall — 2032 mm, which is 51 mm taller than the British imperial standard. Widths run in even inches.
| Door | Leaf | Millimetres | Rough opening | Clear width |
|---|---|---|---|---|
| 24 × 80 in | 24 × 80 in | 610 × 2032 mm | 27.9 × 82.4 in | 22.2 in |
| 28 × 80 in | 28 × 80 in | 711 × 2032 mm | 31.9 × 82.4 in | 26.2 in |
| 30 × 80 in | 30 × 80 in | 762 × 2032 mm | 33.9 × 82.4 in | 28.2 in |
| 32 × 80 in | 32 × 80 in | 813 × 2032 mm | 35.9 × 82.4 in | 30.2 in |
| 36 × 80 in | 36 × 80 in | 914 × 2032 mm | 39.9 × 82.4 in | 34.2 in |
Accessibility asks for clear width, not door width
American guidance asks for 32 inches of clear opening, and a 32-inch door does not give it — about 45 mm goes to the leaf and stop, leaving roughly 30.2 inches. A 36-inch door is what actually delivers 32 inches of clear width, which is why accessible design specifies it. British guidance asks for 750 mm clear, which a 762 mm leaf also fails to provide — the 838 mm door is the one that does.
This is the practical reason the rule is worth knowing: the number in the regulation and the number on the door are measuring different things.
Which way the door swings, and why it is named twice
Handing is described from the side the door opens towards you, which is the convention almost everyone gets backwards on the first try. Stand where the door swings to meet you: hinges on the left is a left-hand door, hinges on the right is a right-hand door.
The complication is that American and British suppliers describe the same door differently — a British "left-hand" is frequently an American "right-hand", because the two traditions disagree about which side you stand on. Ordering across the two markets, give the hinge side and the direction of swing in words rather than trusting the label: "hinges on the left, opens away from the hallway" cannot be misread.
Getting it wrong is not fatal for an internal door — most leaves are reversible and the frame is not — but a fire door with intumescent strips, a rebated pair, or anything with a lock morticed to one side is handed for good and cannot be turned round.
Height is standardised harder than width
Door widths vary by room and by country; heights barely move. Britain settled on 1981 mm — 6 feet 6 inches — for internal doors and holds it across nearly every width, and North America uses 80 inches, 2032 mm, just as consistently. A door that is not one of those two heights is either a made-to-order piece or from before the standard.
That consistency is what makes the rough opening arithmetic simple: add the frame and the clearance to a known height rather than measuring it. It is also why a door bought in the wrong country fits the width of an opening and misses the height by 51 mm, which is exactly the two inches between the two standards and far too much to trim off a hollow-core leaf.