What is a standard UK internal door size?

The most common UK internal door size is 1981mm high × 762mm wide (6′6″ × 2′6″). Other standard widths are 610mm (2′0″) for small rooms and en-suites, 686mm (2′3″) for bedrooms, and 838mm (2′9″) for wider openings. Standard thickness is 35mm for hollow core and 44mm for solid core doors.

What size timber is used for door linings?

Standard UK door linings use 32×108mm softwood for walls finished with 12.5mm plasterboard on both sides of a 75mm stud (total wall thickness ~100mm). For thicker walls, use 32×133mm or 32×140mm linings. The lining depth should match the finished wall thickness including plaster.

How do I calculate architrave length per door?

Each side of a door needs 2 architrave legs and 1 head piece. Leg length = door height + architrave width (for the mitre cut) + 10mm margin. Head length = door width + 2× lining thickness + 2× architrave width (for mitre cuts). Allow extra for cutting waste.

What width architrave should I use?

The most common UK architrave widths are 57mm (budget/minimal), 69mm (standard), and 96mm (period/feature). Ogee and torus profiles in 69mm are the most widely used. For period properties, 96mm or wider architrave with more ornate profiles is appropriate.

Do I need door stops?

Yes, door stops are essential. They prevent the door from swinging through the frame and provide a seal point. Standard door stop is a small moulding (typically 12×38mm or 12×44mm) pinned to the inside of the lining. You need 2 leg pieces and 1 head piece per door.

Door Lining & Architrave Calculator

Calculate door lining sets, architrave lengths, door stops and fixings for any number of UK standard internal doors.

Number of Doors

Total doors requiring lining and architrave

Door Width

762mm is the most common UK internal door

Door Height

Standard UK internal door height is 1981mm

Lining Depth

108mm for standard stud wall + plasterboard

Architrave Width

69mm is standard; 57mm minimal; 96mm period

Architrave Sides

Both sides is standard for internal doors

Include wastage allowance

Adds 10% extra for cutting waste and mitres

Wastage Percentage

10% is standard for door linings and architrave

How We Calculate This

This calculator determines the total timber lengths needed for door lining sets, architrave and door stops for any number of doors.

Lining set calculation

Each door needs a lining set of 2 legs and 1 head piece:

Lining leg length = Door Height + 10mm clearance + 32mm (head piece thickness)
Lining head length = Door Width + (2 × 32mm lining thickness)

Architrave calculation

Each side of each door needs 2 architrave legs and 1 head piece:

Architrave leg length = Door Height + Architrave Width + 10mm (for mitre cut allowance)
Architrave head length = Door Width + (2 × Lining Thickness) + (2 × Architrave Width) (for mitre cuts both ends)

Door stop

Door stop per door = (2 × Door Height) + Door Width

UK standard door sizes

610 × 1981mm (2′0″ × 6′6″)
686 × 1981mm (2′3″ × 6′6″)
762 × 1981mm (2′6″ × 6′6″) — most common
838 × 1981mm (2′9″ × 6′6″)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Verify with your supplier.