Doors and Windows

Door and window dimensions

A door is three different widths, and the one on the invoice is never the useful one.

By the Refined Space editorial desk · Updated September 6, 2026 · How we work

On this page (5 sections)

Three widths, and only one of them is useful
Pocket, sliding and bifold: what each one trades
The 18 in on the latch side
Window heads at 80 in, sills at 30 to 42 in
Egress: 5.7 sq ft that a small window cannot deliver

Short answer

A door has a rough opening, a nominal leaf and a clear width, and they differ. A 36 x 80 in (914 x 2032 mm) leaf needs a rough opening of 38 x 82.5 in (965 x 2096 mm) and delivers about 34 in (864 mm) of clear width when open at 90 degrees. Below a 34 in leaf you drop under the 32 in (815 mm) clear width that accessible standards require, so a 32 in door is not a 32 in opening.

The numbers, at a glance

Common interior leaf: 30 x 80 in (762 x 2032 mm)24 to 36 in (610 to 914 mm) in 2 in steps
UK standard leaf: 762 x 1981 mm (30 x 78 in)Shorter than the US 80 in door
Rough opening: Leaf plus 2 in wide, 2.5 in highPlus 51 mm and 64 mm in metric
Accessible clear width: 32 in (815 mm) minimumNeeds a 34 to 36 in (864 to 914 mm) leaf
Floor swept by a 36 in door: 7.1 sq ft (0.65 m2)A 30 in door sweeps 4.9 sq ft (0.46 m2)
Handle height: 34 to 48 in (864 to 1219 mm)36 in (914 mm) typical, 900 to 1,050 mm in the UK
Egress window clear opening: 5.7 sq ft (0.53 m2)Minimum 24 in (610 mm) high, 20 in (508 mm) wide
Egress sill height: 44 in (1,118 mm) maximumMeasured from the finished floor

Openings are where a plan meets a frame, and almost every mistake in them comes from using one number where three are needed. The rough opening belongs to the carpenter, the nominal leaf to the invoice, and the clear width to the person carrying a laundry basket. Decide the clear width first, because it is the only one with a consequence, then work backwards to the leaf and outwards to the framing.

Three widths, and only one of them is useful#

Nominal door sizes step in 2 in (51 mm) from 24 to 36 in (610 to 914 mm), with 80 in (2,032 mm) the standard height in North America and 1,981 mm (78 in) in the UK. The rough opening adds 2 in to the width and 2.5 in (64 mm) to the height for jambs, shims and the gap under the leaf, and rough opening sizes for doors and windows tabulates the pairs. The clear width then subtracts about 2 in for the open leaf and the stop, which is where a nominal 32 in door quietly becomes a 30 in (762 mm) opening and fails the 32 in (815 mm) that accessible standards ask for.

Leaf	Rough opening	Clear width at 90 degrees	Where it belongs
24 x 80 in (610 x 2,032 mm)	26 x 82.5 in (660 x 2,096 mm)	22 in (559 mm)	Closet only
28 x 80 in (711 x 2,032 mm)	30 x 82.5 in (762 x 2,096 mm)	26 in (660 mm)	Small store, tight ensuite
30 x 80 in (762 x 2,032 mm)	32 x 82.5 in (813 x 2,096 mm)	28 in (711 mm)	Common bedroom door
32 x 80 in (813 x 2,032 mm)	34 x 82.5 in (864 x 2,096 mm)	30 in (762 mm)	Fails the accessible minimum
36 x 80 in (914 x 2,032 mm)	38 x 82.5 in (965 x 2,096 mm)	34 in (864 mm)	Entry, accessible routes
762 x 1,981 mm (30 x 78 in)	790 x 2,020 mm	710 mm (28 in)	UK internal standard

The clear width is also the number that decides whether furniture arrives, since a sofa is measured diagonally through the frame rather than squarely. Interior door sizes and rough openings covers the domestic set, exterior door sizes and standards adds the thicker 1.75 in (44 mm) leaves and their thresholds, and measuring the delivery path turns the clear width into the formula that predicts a failed delivery. Door sizes by country sets out why a continental leaf will not fill a British lining.

A door swing is floor area, and it grows as the square

A swinging leaf sterilises a quarter circle whose radius is the door width, so the area is roughly 0.79 times the width squared. A 30 in (762 mm) door takes 4.9 sq ft (0.46 m2). A 36 in (914 mm) door takes 7.1 sq ft (0.65 m2). Widening a door by 20 per cent costs 44 per cent more floor, because the relationship is quadratic and nothing about the leaf is linear once it moves.

Two consequences follow that the size tables never state. The first is that a door is the largest single piece of furniture in a small room: in a 5 x 8 ft (1.5 x 2.4 m) bathroom, one 30 in door occupies an eighth of the floor, more than the basin. The second is a fair test for a pocket door. It buys back the whole quarter circle in exchange for roughly twice the door width in wall, half of which can carry nothing: no socket, no switch, no shelf fixing, no rail. On a 32 in (813 mm) door that trade is 4.9 sq ft (0.46 m2) of floor recovered for about 32 in of dead wall, which is worth taking in a bathroom or an ensuite and rarely worth taking in a corridor, where the wall was doing useful work and the floor was not.

Pocket, sliding and bifold: what each one trades#

The alternatives to a swing are all trades rather than upgrades. A pocket door needs a wall about twice its own width and gives up the fixings in it. A sliding or barn door needs the same run of wall but keeps the fixings and loses the acoustic seal, since the leaf hangs proud rather than closing into a stop: pocket and sliding door dimensions sets out the track and clearance dimensions for both. Bifolds halve the projection instead of removing it and stack 5 to 6 in (127 to 152 mm) per pair of leaves at the jamb, which matters most on a wardrobe where that stack sits across the hanging rail: bifold and folding door dimensions gives the sizes. Wide glazed openings behave differently again, because a sliding patio door only ever opens half its width while a French pair opens all of it and needs the floor to prove it, as French, patio and sliding door dimensions shows.

The 18 in on the latch side#

A door that opens is not a door that works. The space in front of it decides that, and the governing figure is the latch-side clearance: 18 in (457 mm) on the pull side of a front approach, so a hand can hold the handle while the body stands clear of the arc. Push-side and side approaches carry their own numbers, all set out in door swing, clearance and approach space and in the accessible versions in accessible door widths, hardware and approach. Hardware sits at 34 to 48 in (864 to 1,219 mm), commonly 36 in (914 mm), with hinges 7 in (178 mm) from the head, 11 in (279 mm) from the foot and the third centred between: door handle, lock and hinge heights has the full set, and the general case for the whole house is in door sizes, swings and the space they need.

Window heads at 80 in, sills at 30 to 42 in#

A window is fixed by its head, its sill and the module it is made in. The head almost always aligns with the door head at 80 in (2,032 mm) or a little above, because that alignment is what makes a room read as ordered, and standard window sizes shows how manufacturers step widths and heights in 2 in (51 mm) increments to suit it. The sill is the variable: 30 to 36 in (76 to 91 cm) in a living room, 42 in (107 cm) minimum over a kitchen counter so the sill clears the worktop and its upstand, and lower in a bedroom where a seated view matters more. Window sill and head heights works through the cases, and roof openings follow the rafter module instead, at 16 or 24 in (406 or 610 mm) centres, which is why skylight and roof window dimensions look like an unfamiliar set of sizes.

Egress: 5.7 sq ft that a small window cannot deliver#

Two window numbers are not negotiable. A bedroom needs an escape opening of 5.7 sq ft (0.53 m2) net clear, at least 24 in (610 mm) high and 20 in (508 mm) wide, with the sill no more than 44 in (1,118 mm) above the floor, and those minimums cannot be met at the same time by a small window: egress window sizes and sill heights does the arithmetic. Fall protection is the other, since a sill under 24 in (610 mm) with more than 72 in (1,829 mm) of drop outside needs an opening limiter under the IRC. Both clauses, and their British equivalents, are indexed in the standards and codes reference.

Frequently asked questions#

What is the standard rough opening for a door?

The leaf width plus 2 in (51 mm) and the leaf height plus 2.5 in (64 mm), so a 30 x 80 in door frames at 32 x 82.5 in (813 x 2096 mm). The extra covers a 3/4 in (19 mm) jamb each side, the shim gap and the clearance under the door. Check the shim gap the manufacturer wants, because some prefabricated units ask for a full 2.5 in on width.

Why does a 32 inch door not give 32 inches of clear width?

Because clear width is measured from the face of the open leaf to the stop on the far jamb, and that takes roughly 2 in (51 mm) out of the nominal size. A 32 in (813 mm) door delivers about 30 in (762 mm), which is under the 32 in (815 mm) that ADA and ICC A117.1 require. A 34 in leaf is the smallest that passes, and 36 in (914 mm) is the safe choice.

How much floor does a door swing take?

A quarter circle of radius equal to the leaf width, so 7.1 sq ft (0.65 m2) for a 36 in (914 mm) door and 4.9 sq ft (0.46 m2) for a 30 in (762 mm) one. The area rises with the square of the width, which means widening a door by 20 per cent costs 44 per cent more swept floor. In a 5 x 8 ft (1.5 x 2.4 m) bathroom, one 30 in door occupies an eighth of the room.

How high should a door handle be?

Thirty-four to 48 in (864 to 1,219 mm) above the floor is the accessible range, and 36 in (914 mm) is the usual centre in North America. UK practice under Approved Document M puts levers between 900 and 1,050 mm. Deadbolts sit higher, around 44 to 48 in (1,118 to 1,219 mm), and both should be operable with a closed fist, which rules out a knob.

What size window counts as an egress window?

A net clear opening of 5.7 sq ft (0.53 m2), reduced to 5.0 sq ft (0.46 m2) for a ground floor window, with a minimum clear height of 24 in (610 mm) and a minimum clear width of 20 in (508 mm), and a sill no more than 44 in (1,118 mm) above the finished floor. Net clear means the hole once the sash is open, not the frame size.

How high should a window sill be?

Thirty to 36 in (76 to 91 cm) in a living room, which clears furniture and gives a seated view, and at least 42 in (107 cm) behind a kitchen counter so the sill sits above the 36 in (91 cm) worktop with a tiled upstand. Where the sill is below 24 in (610 mm) and the drop outside exceeds 72 in (1,829 mm), the IRC requires an opening limiter.

How much wall does a pocket door need?

Roughly twice the door width plus 1 in (25 mm), so a 32 in (813 mm) pocket door needs about 65 in (1,651 mm) of wall run. The pocket half of that wall carries no sockets, no switches and no shelf fixings, which is the real cost. In exchange it returns the whole quarter circle of swing to the floor plan.

Are UK and US door sizes interchangeable?

No. The common UK internal leaf is 762 x 1,981 mm, which is 30 x 78 in, so it is 2 in shorter than a US 80 in door, and UK leaves are 35 mm thick against the US 1.375 in (35 mm) internal and 1.75 in (44 mm) external. Frames, hinges and latch backsets differ too, so replacing one system with the other means new linings.

Sources and standards referenced#

International Residential Code International Code CouncilEgress opening sizes, sill heights, window fall protection and door requirements
2010 ADA Standards for Accessible Design US Department of JusticeClear width of 32 in, manoeuvring clearances and hardware heights
Approved Document M: Access to and use of buildings UK GovernmentClear opening widths and door hardware heights in dwellings
Architects' Data Ernst Neufert, Wiley-BlackwellDoor and window module sizes, swing geometry and sill heights
BS 4787: Internal and external wood doorsets, door leaves and frames British Standards InstitutionUK door leaf sizes and frame tolerances

We cite published codes, industry planning guidelines and manufacturer specifications. Where a figure is our own recommendation rather than a published standard, the text says so. See how we measure.