Door sizes, swings and the space they need

Standard sizes, US and metric#

Doors come in a short list of stock sizes because the framing, the hardware and the delivery lorry all assume that list. Going off it is possible and expensive.

Use	US nominal	Metric equivalent	Clear width when open 90 degrees
Small cupboard, linen press	24 x 80 in	610 x 2032 mm	about 22 in (56 cm)
Secondary bathroom, small closet	28 x 80 in	711 x 2032 mm	about 26 in (66 cm)
Common interior door	30 x 80 in	762 x 2032 mm	about 28 in (71 cm)
Bedroom, generous interior	32 x 80 in	813 x 2032 mm	about 30 in (76 cm)
Accessible interior, main rooms	36 x 80 in	914 x 2032 mm	about 34 in (86 cm)
UK standard leaf	762 x 1981 mm	30 x 78 in	about 28 in (71 cm)
UK wide leaf	838 x 1981 mm	33 x 78 in	about 31 in (79 cm)
UK true metric leaf	826 x 2040 mm	32.5 x 80.3 in	about 30 in (76 cm)

Two heights dominate. 80 in (2032 mm) is the US standard and 1981 mm (6 ft 6 in) the UK imperial-metric standard, with 2040 mm used for true metric leaves. Taller 84 in (213 cm) and 96 in (244 cm) doors exist and change the proportion of a room considerably: see ceiling height and proportion before ordering them.

Rough opening: the number the carpenter needs#

Rough opening = door width + 2 in (5 cm), door height + 2.5 in (6 cm).

The 2 in is two jamb legs at roughly 0.75 in (19 mm) each plus about 0.25 in (6 mm) of shim space per side. The extra half inch in height accounts for the head jamb plus packing above the floor finish. If you are laying a thick floor later, add its build-up: 0.75 in (19 mm) of engineered board plus underlay is enough to make an 80 in door bind.

A 32 x 80 in prehung unit therefore wants a 34 x 82.5 in (86 x 210 cm) hole. Order the door before the framing goes up, not after.

Clear width is the only width that matters#

Nominal width is what you buy. Clear width is what you walk through.

With the leaf open at 90 degrees, the opening is reduced by the thickness of the slab standing in it (about 1.375 in or 35 mm for a standard interior door) and by the door stop on the far jamb (about 0.5 in or 13 mm). Round it to 2 in (5 cm) off nominal.

IRC R311.2 requires at least one egress door in a dwelling with 32 in (81 cm) clear width and 78 in (198 cm) clear height, measured the same way. That is the same number as the ADA figure and it is not a coincidence: 32 in is the width of a manual wheelchair plus knuckles.

The swing, drawn#

Approach clearances, the part everyone forgets#

A door you can physically get through is not the same as a door you can operate. To pull a door open you have to stand beside the leaf, not in front of it, which means dead wall on the latch side.

Approach	Side	Latch-side clearance	Depth
Front approach	Pull	18 in (46 cm)	60 in (152 cm)
Front approach	Push	0 in	48 in (122 cm)
Front approach, push, with closer and latch	Push	12 in (30 cm)	48 in (122 cm)
Hinge-side approach	Pull	36 in (91 cm)	60 in (152 cm)
Latch-side approach	Pull	24 in (61 cm)	48 in (122 cm)

These are the ADA 2010 maneuvering clearances (404.2.4.1). In a private house they are best practice rather than law, but the 18 in pull-side figure is worth honouring everywhere, because it is also the amount of space a person carrying a laundry basket needs to open a door without putting it down. A door tight into a corner on its latch side is annoying for everyone, not just wheelchair users.

Swings, pockets and sliders#

Hinged. The swing is a quarter circle of radius equal to the door width. For a 32 in (81 cm) door that is about 5.6 sq ft (0.52 sq m) of floor that no fixed object can occupy. Circulation may pass through it, seating and storage may not.

Pocket. Removes the swing entirely. Costs a stud bay: the pocket cassette is the door width plus about 1 in (2.5 cm), and the wall must be free of sockets, switches, cabling and pipework for that whole length. Standard 2x4 framing accommodates a pocket cassette, but the wall loses most of its structural and service value. Pocket doors also seal poorly for sound, so avoid them between a bedroom and a living space.

Surface-mounted slider (barn door). No wall cavity needed, but the leaf must be wider than the opening by 2 in (5 cm) per side to seal reasonably, and it needs clear wall equal to its own width to slide onto. It cannot be sealed, cannot be locked conventionally, and it hides the wall it parks on.

Bifold. Halves the swing to roughly half the door width, at the cost of a slot of dead space at the fold and hardware that wears. Best confined to closets and cupboards; see closet dimensions.

Getting furniture through#

The nominal door width is not the constraint on a delivery: the clear width is, and a sofa turns on its diagonal rather than its depth. A 30 in (76 cm) door gives about 28 in (71 cm) clear, which is enough for a sofa whose height and depth combine to a diagonal under 28 in. That is a real filter, and the arithmetic is worked through in measuring the delivery path.

If a door is a known bottleneck, the fastest fix is not a bigger door. It is removing the leaf and the stop, which recovers about 2 in (5 cm) of clear width in ten minutes with a screwdriver, and removing the architrave on one side, which can recover another 0.75 in (2 cm).

Specifying a door in the right order#

1. Decide the swing direction and side first, from the room plan, not from the door schedule. This is the decision that cannot be changed later without patching a wall.
2. Check the latch-side clearance on the pull side. If it is under 18 in (46 cm), swap the hinge side or the swing direction.
3. Set the nominal width from the clear width you need, adding 2 in (5 cm).
4. Confirm the rough opening with the framer: nominal plus 2 in wide, plus 2.5 in high, plus your finished floor build-up.
5. Only then choose the leaf style, because a solid-core 36 in door weighs around 70 lb (32 kg) and needs three hinges and a firm jamb fixing.