Plasterboard calculator

Walls and ceilings in — boards, screws, tape and jointing compound or skim out.

Work out boards and fixings

Enter the walls (total length of wall × height) and the ceiling. Openings come off the wall area.

Walls

Openings to take off

Ceiling (0 for none)

—
Wall area / ceiling area—
Boards — walls / ceiling—
Drywall screws—
Joint tape—
Jointing compound—

Waste % is added to boards, tape and compound. Screws include 10% for drops. Tape and compound are worked out from the joint length (board edges shared with neighbours); add internal angles if you tape them.

Quantities are estimates for ordering. Follow the board manufacturer's system specification for fixings and centres.

Plasterboard coverage and fixings

Standard board sizes and the figures the calculator uses.

Plasterboard sizes — coverage, screws and joints
Boardm²Per 10 m²Screws wallScrews ceilingJoint m/m²
2400 × 1200 mm2.88427491.25
2700 × 1200 mm3.24430561.20
1800 × 900 mm1.62721301.67

Screws: walls on 600 mm studs at 300 mm centres, ceilings on 400 mm joists at 230 mm centres (British Gypsum general guidance). Joint m/m² = metres of joint per m² of board, each board sharing its edges with its neighbours. Per 10 m² is before waste.

How to work out plasterboard

Measure each wall length × height, add them up and take off windows and doors. Measure the ceiling length × width. Divide each by the area of one board and round up — but do walls and ceilings separately, because boards are cut differently and offcuts from one rarely suit the other.

Screws

British Gypsum's general guidance is screws at 300 mm centres on partitions and 230 mm centres in the field of a ceiling board (150 mm at board ends on ceilings). A 2400 × 1200 board on 600 mm studs takes 3 lines of 9 = 27 screws; on a ceiling with 400 mm joists it takes 7 lines of 7 = 49. Always follow the system specification — fire and acoustic systems often need closer centres or two layers.

Tape, compound or skim

Each board shares its edges with its neighbours, so a wall of 2400 × 1200 boards has about 1.25 m of joint per m². For a taped and jointed finish, British Gypsum's data puts tapered-edge flat joints at about 12 kg of joint filler for the taping coat plus 6 kg for each of two finishing coats per 100 m of joint — roughly 0.24 kg per metre. For a skim finish, scrim the joints and allow one 25 kg bag of Multi-Finish per 10 m² at 2 mm.

Questions dryliners ask

How many plasterboards do I need for a room?

Add up the wall area (length × height of each wall, minus windows and doors) and the ceiling area, then divide by the board area — 2.88 m² for a 2400 × 1200 board — and round up. Add about 10% for cuts and damage.

How many screws per sheet of plasterboard?

On walls with studs at 600 mm and screws at 300 mm centres, a 2400 × 1200 board takes about 27 screws. On a ceiling with joists at 400 mm and screws at 230 mm centres, about 49. Check the system specification for fire or acoustic walls.

What are the screw centres for plasterboard?

British Gypsum's general guidance is 300 mm centres on partitions and 230 mm centres in the field of ceiling boards, with 150 mm at board ends on ceilings and 200 mm at external angles. Specific systems can differ.

How much jointing compound per board?

For tapered-edge flat joints, about 0.24 kg per metre of joint across the taping and two finishing coats (British Gypsum data). A 2400 × 1200 board has about 3.6 m of joint, so roughly 0.9 kg per board before waste.

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Quantities are estimates for ordering. Follow the board manufacturer's system specification for fixings and centres.